AIM: To develop a PCR assay using mutant-specific primers to detect mutation of tyrosine-methionine-aspartate-aspartate (YMDD) motif of HBV to tyrosine-valine-aspartate-aspartate (YVDD) or tyrosine-isoleucine-aspartat...AIM: To develop a PCR assay using mutant-specific primers to detect mutation of tyrosine-methionine-aspartate-aspartate (YMDD) motif of HBV to tyrosine-valine-aspartate-aspartate (YVDD) or tyrosine-isoleucine-aspartate-aspartate (YIDD).METHODS: Cloned wild-type and mutant HBV sequences were used as templates to test the sensitivity and specificity of the assay. A variety of primer construction, primer concentration, dNTP concentration, and annealing temperature of primers were systematically examined. Pair primers specifi c to rtL180M and rtM204V were selected for YVDD detection. Primer specif ic to rtM204I with an additional 3’-penultimate base mismatched to both the mutant and wild-type sequence was selected for YIDD detection. We applied this assay to study YMDD mutants in 28 chronic hepatitis B patients before and after lamivudine treatment.RESULTS: We could detect as little as 0.001%-0.00001% of mutant viruses coexisting in 108-109 copies of wild-type HBV using this assay. YMDD mutants were detected in 8 of 12 HBeAg-positive patients and 8 of 16 HBeAg-negative patients before lamivudine treatment. After treatment, two more patients in HBeAg-positive patients and seven more patients in HBeAg-negative patients developed YMDD mutations. CONCLUSION: We developed a highly sensitive and specifi c assay for detecting YMDD mutants. This assay can be applied to monitor chronic hepatitis B patients before and during lamivudine treatment.展开更多
Ectothermic organisms may expand their thermal tolerance by producing multiple protein isoforms with differing thermal sensitivities.While such isoforms commonly originate from allelic variation at a single locus(allo...Ectothermic organisms may expand their thermal tolerance by producing multiple protein isoforms with differing thermal sensitivities.While such isoforms commonly originate from allelic variation at a single locus(allozymes)or from gene duplication that gives rise to paralogs with distinct thermal responses,this study investigated mRNA editing as an alternative,post-transcriptional mechanism for generating mRNA variants.Cytosolic malate dehydrogenase(cMDH)was examined in foot tissue of two congeners of the marine mussel genus Mytilus,which occupy different thermal environments.Multiple editing events were detected within the mRNA coding region in both species.Editing sites were species-specific,with no shared positions identified.In M.coruscus,editing occurred at 117,123,135,190,195,204,279,and 444,while in M.galloprovincialis,editing was detected at 216 and 597.Each species exhibited multiple edited mRNA variants,and these isoforms were associated with differential protein expression.These findings suggest that mRNA editing may contribute an additional layer of molecular variation.The generation of diverse mRNA isoforms from a single DNA coding sequence may enhance enzymatic flexibility across temperature ranges,supporting eurythermal physiological performance and mitigating thermal stress.Moreover,the presence of multiple edited transcripts within individual organisms raises important caveats about the limitations of approaches that deduce amino acid sequences or estimate adaptive variation solely from genomic data.展开更多
Leaf acid phosphatase (APase) activities of 274 soybean genotypes were surveyed under field conditions with two levels of P supplies, and a nutrient solution culture experiment with eight selected genotypes was subseq...Leaf acid phosphatase (APase) activities of 274 soybean genotypes were surveyed under field conditions with two levels of P supplies, and a nutrient solution culture experiment with eight selected genotypes was subsequently conducted under greenhouse conditions to further characterize APase activity and its isoform expression induced by P starvation. Results from the field experiment showed that there was a great genotypic variation for leaf APase activity among the tested soybean genotypes from different origins, and APase activity in many of the tested genotypes (about 60%) was generally increased in the treatment without P fertilizer addition. Results from the nutrient solution culture experiment showed that APase activity in all the eight tested genotypes was generally enhanced by P starvation. Six isoforms of APases were detected in isoelectric focusing gels with samples from both young and old leaves. The activity of all the six isoforms was increased by P starvation, but no new APase isoform was induced. Our results suggest that leaf APase activity could serve as an enzymatic indicator of P starvation for soybean; the increase in leaf APase activity under low P stress was mainly caused by the increase in the activity of existing isoforms but not by the induction of new isoforms.展开更多
Objective: To investigate the role of PKC isoforms in the regulation of LPS-triggered tumoricidal activity in macrophages and further elucidate its signal mechanisms. Methods: Two macrophage cell lines (P388D1 and RAW...Objective: To investigate the role of PKC isoforms in the regulation of LPS-triggered tumoricidal activity in macrophages and further elucidate its signal mechanisms. Methods: Two macrophage cell lines (P388D1 and RAW264.7) were stimulated by LPS alone, or with long-term of PMA pretreatment. Then cytotoxicities to P815 cells (by MTT assay) and IL-1, TNF- (by ELISA) and nitric oxide (NO) production (by Griess reagent) in supernatants were measured. Western blot for PKC isoforms after long-term PMA pretreatment was analyzed. Results: RAW264.7 cells were stimulated with LPS to kill target tumor cells P815, whereas P388D1 cells failed to develop such an ability. Down-regulation of PKC isoforms by chronic treatment with PMA significantly inhibited the LPS-induced cytotoxicity in RAW264.7 cells. In unstimulated state, Western blotting with rabbit antiserum specific for the PKC, 1, 2, or showed all 5 isoforms were detected in P388D1 cells, while only PKC, PKC1 and PKC were detected in RAW264.7 cells. Exposure of the cells to long-term of PMA treatment significantly down-regulated the expression of PKC, PKC1 and PKC in RAW264.7 cells. But in P388D1 cells, although PKC, PKC and PKC were down-regulated, the expression of PKC1 and PKC2 could not be regulated. Comparing with LPS-induced IL-1, TNF- and NO production by the two macrophage cell lines, P388D1 failed to produce NO. In RAW264.7 cells, LPS-induced NO production and antitumor activity was attenuated by the addition of L-NAME, an iNOS inhibitor. Conclusion: The results indicated a critical role of PKC in LPS-induced antitumor activity and this cytotoxicity is mainly due to PKC- mediated NO production by RAW264.7 cells, but not a direct cytotoxic activity.展开更多
[Objective] This study aimed to analyze the effects of temperature on the expression of AGPase isoform genes in rice endosperm during milk stage. [Method] Different temperature treatments （33 and 25 ℃ of daily mean ...[Objective] This study aimed to analyze the effects of temperature on the expression of AGPase isoform genes in rice endosperm during milk stage. [Method] Different temperature treatments （33 and 25 ℃ of daily mean temperature for high and normal temperature treatments, respectively） and the real-time fluorescence quantitative PCR （ FQPCR） were used to analyze the expression patterns of seven isoforms （AGPS1, AGPS2a, AGPS2b, AGPL1, AGPL2, AGPL3 and AGPL4） of ADPglucose pyrophosphorylase （AGPase） which was the key enzyme in starch synthesis and metabolism in rice endosperm of two rice varieties Teqing and Thai Fragrant Rice. [Result] The AGPase isoforms AGPS2b, AGPL2 and AGPL3 had much higher expression than the other four isoforms, thus they were thought to be the main expression patterns of AGPase in rice endosperm. The relative expressions of AGPL2 was the highest among all the isoforms. The relative expressions of AGPS2b, AGPL2 and AGPL3 were higher in the normal temperature treatment than in the high temperature treatment in both rice varieties. The relative expression of the three enzyme genes in milk stages in Teqing was higher than those in Thai Fragrant Rice under different temperature treatments. [Conclusion] This study provides a theoretical basis for further use of molecular biology techniques to cultivate stable high-quality rice varieties.展开更多
Complex genetic relationships between neurodegenerative disorders and neuropsychiatric symptoms have been shown, suggesting shared pathogenic mechanisms and emphasizing the potential for developing common therapeutic ...Complex genetic relationships between neurodegenerative disorders and neuropsychiatric symptoms have been shown, suggesting shared pathogenic mechanisms and emphasizing the potential for developing common therapeutic targets. Apolipoprotein E(APOE) genotypes and their corresponding protein(Apo E) isoforms may influence the biophysical properties of the cell membrane lipid bilayer. However, the role of APOE in central nervous system pathophysiology extended beyond its lipid transport function. In the present review article, we analyzed the links existing between APOE genotypes and the neurobiology of neuropsychiatric symptoms in neurodegenerative and vascular diseases. APOE genotypes(APOE ε2, APOE ε3, and APOE ε4) were implicated in common mechanisms underlying a wide spectrum of neurodegenerative diseases, including sporadic Alzheimer's disease, synucleinopathies such as Parkinson's disease and Lewy body disease, stroke, and traumatic brain injury. These shared pathways often involved neuroinflammation, abnormal protein accumulation, or responses to acute detrimental events. Across these conditions, APOE variants are believed to contribute to the modulation of inflammatory responses, the regulation of amyloid and tau pathology, as well as the clearance of proteins such as α-synuclein. The bidirectional interactions among Apo E, amyloid and mitochondrial metabolism, immunomodulatory effects, neuronal repair, and remodeling underscored the complexity of Apo E's role in neuropsychiatric symptoms associated with these conditions since from early phases of cognitive impairment such as mild cognitive impairment and mild behavioral impairment. Besides Apo E-specific isoforms' link to increased neuropsychiatric symptoms in Alzheimer's disease(depression, psychosis, aberrant motor behaviors, and anxiety, not apathy), the APOE ε4 genotype was also considered a significant genetic risk factor for Lewy body disease and its worse cognitive outcomes. Conversely, the APOE ε2 variant has been observed not to exert a protective effect equally in all neurodegenerative diseases. Specifically, in Lewy body disease, this variant may delay disease onset, paralleling its protective role in Alzheimer's disease, although its role in frontotemporal dementia is uncertain. The APOE ε4 genotype has been associated with adverse cognitive outcomes across other various neurodegenerative conditions. In Parkinson's disease, the APOE ε4 allele significantly impacted cognitive performance, increasing the risk of developing dementia, even in cases of pure synucleinopathies with minimal co-pathology from Alzheimer's disease. Similarly, in traumatic brain injury, recovery rates varied, with APOE ε4 carriers demonstrating a greater risk of poor long-term cognitive outcomes and elevated levels of neuropsychiatric symptoms. Furthermore, APOE ε4 influenced the age of onset and severity of stroke, as well as the likelihood of developing stroke-associated dementia, potentially due to its role in compromising endothelial integrity and promoting blood–brain barrier dysfunction.展开更多
Aim: To investigate the androgen receptor (AR) isoforms and its variability of expression in human and rat prostatictissues. Methods: Human benign prostatic hyperplasia (BPH) and prostatic cancer tissues were obtained...Aim: To investigate the androgen receptor (AR) isoforms and its variability of expression in human and rat prostatictissues. Methods: Human benign prostatic hyperplasia (BPH) and prostatic cancer tissues were obtained from pa-tients undergoing prostatectomy, and rat ventral prostate was incised 3 days after castration. Forty-one AR-positive BPHspecimens, 3 prostatic cancer specimens, and 6 rat prostates were used. After processing at 4℃, the tissues were ex-amined by means of high resolution isoelectric focusing (IEF) technique to determine their AR isoforms. Results:From the prostatic specimens, 3 types of AR isoforms were detected with pI values at 6.5, 6.0, and 5.3. In humanBPH tissues, 15/41 (36.6%) specimens showed all the three types of isoforms, while 19/41 (46.3%) showed 2 iso-fora at various combinations and 7/41 (17.1%), 1 isoform. For the 3 prostatic cancer specimens, one showed 3 iso-forms, one, 2 isoforms, and the other failed to show any isoform. All rat prostatic tissues showed 2 isoforms at differ-ent combinations. Binding of ~3H-dihydrotestosterone (DHT) to the isoforms was inhibited by the addition of 100-foldexcess of DHT or testosterone, but not progesterone, oestradiol or diethylstilboestrol. Conclusion: AR isoforms aredifferent in different patients. Although their genesis is not clear, the therapeutic implication of the present observationappears to be interesting, that may help clarifying the individual differences in the response to hormonal therapy.(Asian J Androl 2000 Dec; 2: 307-310)展开更多
Protein arginine methyltransferases(PRMTs) catalyze the methylation of a variety of protein substrates, many of which have been linked to the development, progression and aggressiveness of different types of cancer. M...Protein arginine methyltransferases(PRMTs) catalyze the methylation of a variety of protein substrates, many of which have been linked to the development, progression and aggressiveness of different types of cancer. Moreover, aberrant expression of PRMTs has been observed in several cancer types. While the link between PRMTs and cancer is a relatively new area of interest, the functional implications documented thus far warrant further investigations into its therapeutic potential. However, the expression of these enzymes and the regulation of their activity in cancer are still significantly understudied. Currently there are nine main members of the PRMT family. Further, the existence of alternatively spliced isoforms for several of these family members provides an additional layer of complexity. Specifically, PRMT1, PRMT2, CARM1 and PRMT7 have been shown to have alternative isoforms and others may be currently unrealized. Our knowledge with respect to the relative expression and the specific functions of these isoforms is largely lacking and needs attention. Here we present a review of the current knowledge of theknown alternative PRMT isoforms and provide a rationale for how they may impact on cancer and represent potentially useful targets for the development of novel therapeutic strategies.展开更多
In this study, the gene encoding hemocyanin subunit L, Lv Hc L, was cloned from Litopenaeus vannamei and the genomic organization was characterized. This gene was diverse with many SNPs and also had at least four isof...In this study, the gene encoding hemocyanin subunit L, Lv Hc L, was cloned from Litopenaeus vannamei and the genomic organization was characterized. This gene was diverse with many SNPs and also had at least four isoforms, while one of them（Lv Hc L4） only had two exons and the exon2 was missed. Transcription analysis showed that these isoforms of Lv Hc L were up-regulated after WSSV challenge in WSSV-resistant shrimp, while the transcriptions were decreased constantly in WSSV-susceptible shrimp. It is suggested that the hemocyanin had rich polymorphism and was involved in the antiviral response. These results could extend our previous findings and provide insights into the immune feature of hemocyanin, which would be helpful for further studies aimed at antiviral mechanism in invertebrate.展开更多
AIM:To investigate three isoforms of survivin in colorectal adenocarcinomas.METHODS:We used the LightCycler Technology(Roche),along with a common forward primer and reverse primers specific for the splice variants and...AIM:To investigate three isoforms of survivin in colorectal adenocarcinomas.METHODS:We used the LightCycler Technology(Roche),along with a common forward primer and reverse primers specific for the splice variants and two common hybridization probes labeled with fluorescein and LightCycler-Red fluorophore(LC-Red 640).Real time quantitative polymerase chain reaction(PCR) was performed on cDNAs from 52 tumor specimens from colorectal cancer patients and 10 unrelated normal colorectal tissues.In the patients group,carcinoembryonic antigen(CEA) and CA19-9 tumor markers were also measured immunochemically.RESULTS:Wild type survivin mRNA isoform was expressed in 48%of the 52 tumor samples,survivin-2b in 38%and survivin-ΔΕx3 in 29%,while no expression was found in normal tissues.The mRNA expression of wild type survivin presented a significant correlation with the expression of the ratio of survivin-2b,survivin-ΔΕx3,survivin-2b/wild type survivin and survivin-ΔΕx3/wild type survivin(P<0.001).The mRNA expression of wildsurvivin and survivin-ΔΕx3 was related with tumor size and invasion(P=0.006 and P<0.005,respectively).A significant difference was found between survivin-2b and morphologic cancer type.Also,the ratio of survivin-ΔEx3/ wild-survivin was significantly associated with prognosis.No association was observed between the three isoforms and grade,metastasis,Dukes stage and gender.The three isoforms were not correlated with CEA and CA19-9.CONCLUSION:Survivin isoforms may play a role in cell apoptosis and their quantification could provide information about clinical management of patients suffering from colorectal cancer.展开更多
Nitrogen is a key element to control the growth and yield of crops. Fertilizer urea nitrogen (N) 60,45, and 30 kg/hm2 was applied at three different stages, midtillering, panicle initiation, and flowering, of the grow...Nitrogen is a key element to control the growth and yield of crops. Fertilizer urea nitrogen (N) 60,45, and 30 kg/hm2 was applied at three different stages, midtillering, panicle initiation, and flowering, of the growth and development of rice plants, respectively. At both midtillering and panicle initiation, the total activity of glutamine synthetase (GS) in rice roots and leaves was incrased remarkably as a result of a large amount of ammonia absorbed by roots. Native-PAGE and activity staining showed that the increase of total activity in rice roots and leaves was due to the synthesis of GSrb in roots and GS2 in leaves and that the activity of GSra in roots and GS1 in leaves remained constant. The results showed that the assimilation of external nitrogen was carried out by GSrb but not GSra in rice roots and that the activitry of GS2 was induced also by the external nitrogen, and that GSrb played main role in meeting the needs of the rapid tillering for nitrogen. At flowering, the activity of GS in rice roots and leaves did not change almost after topdressing. These rssults suggest that the change of GS activity in rice roots may use as a measure of the utilization efficiency of the fertilizer.展开更多
AIM To investigate the role of Δ133p53 isoform in nuclear factor-κB(NF-κB) inhibitor pyrrolidine dithiocarbamate(PDTC)-mediated growth inhibition of MKN45 gastric cancer cells.METHODS The growth rate of MKN45 cells...AIM To investigate the role of Δ133p53 isoform in nuclear factor-κB(NF-κB) inhibitor pyrrolidine dithiocarbamate(PDTC)-mediated growth inhibition of MKN45 gastric cancer cells.METHODS The growth rate of MKN45 cells after treatment with different concentrations of only PDTC or PTDC in combination with cisplatin was detected by the CCK-8 assay. m RNA expression levels of Δ133p53, p53β, and the NF-κB p65 subunit and p65 protein levels were detected by reverse transcription-polymerase chain reaction(RT-PCR) and immunofluorescence, respectively. Growth of MKN45 cells was significantly inhibited by PDTC alone in a dose-dependent manner(P < 0.01). Moreover, the inhibitory effect of cisplatin was remarkably enhanced in a dose-dependent manner by co-treatment with PDTC(P < 0.01).RESULTS RT-PCR analysis revealed that m RNA expression of p65 was curbed significantly in a dose-dependent manner by treatment with only PDTC(P < 0.01), and this suppressive effect was further enhanced when co-treated with cisplatin(P < 0.01). With respect to the other p53 isoforms, m RNA level of Δ133p53 was significantly reduced in a dose-dependent manner by treatment with only PDTC or PTDC in combination with cisplatin(P < 0.01), whereas p53β m RNA expression was not altered by PDTC treatment(P > 0.05). A similar tendency of change in p65 protein expression, as observed for the corresponding m RNA, was detected by immunofluorescence analysis(P < 0.01). Pearson correlation analysis demonstrated that Δ133p53 and p65 m RNA expression levels were positively related, while no significant relationship was observed between those of p65 and p53β(r = 0.076, P > 0.01).CONCLUSIONΔ133p53 isoform(not p53β) is required in PDTCinduced inhibition of MKN45 gastric cancer cells, indicating that disturbance in the cross-talk between p53 and NF-κB pathways is a promising target in pharmaceutical research for the development of treatment strategies for gastric cancer.展开更多
AIM:To analyze the risk of coronary heart disease in patients with type 2 diabetes mellitus(T2DM)receiving standard medical treatment.METHODS:We performed a retrospective chart analysis of 269 middle-aged patients(age...AIM:To analyze the risk of coronary heart disease in patients with type 2 diabetes mellitus(T2DM)receiving standard medical treatment.METHODS:We performed a retrospective chart analysis of 269 middle-aged patients(age 45-64 years,mean age,53.9±5.5 years)with T2DM and without atherosclerotic cardiovascular events who underwent typing to determine their apolipoprotein E(apoE)isoforms.The apoE isoforms were determined using isoelectric focusing,followed by immunoblotting.We retrospectively evaluated the charts of the 269 patients,recorded between their first visit to the hospital(the study's start point,between 1987 and 1992)and the occurrence of an atherosclerotic cardiovascular event(the study's endpoint)or January 2004,whichever came first.The age-adjusted mean values and the prevalences of covariates were calculated to compare the laboratory data among the apoE phenotypes.To investigate the association of risk factors with the incidence of coronary heart disease during the follow-up period,monovariate and multivariate Cox regression models were used.RESULTS:At enrollment,the mean serum low density lipoprotein(LDL)cholesterol levels were lowest(2.92± 0.89 mmol/L)among the subjects with apoE2(apoE2/2 or apoE2/3)and highest(3.52±0.77 mmol/L)among the subjects with apoE4(apoE3/4 or apoE4/4).No significant differences in mean age or the percentage of smokers were observed among the three groups.Furthermore,no significant differences were observed in the systolic and diastolic blood pressures,body mass index,HbA1c level or serum triglyceride levels among the three groups.There were 47 cases of coronary heart disease over 3285 person-years of follow-up.An age-adjusted multivariate Cox proportional model identified diabetic retinopathy(hazard ratio,2.38,95% CI:1.28-4.43,P=0.006),a high systolic blood pressure(hazard ratio,1.04,95%CI:1.02-1.06,P<0.001) and high HbA1c values(hazard ratio,1.19,95%CI:1.02-1.38,P=0.0029),but not the LDL cholesterol value at enrollment(hazard ratio,1.01,95%CI:0.97-1.05,P=0.77)nor the specific apoE isoform,as significant predictors of coronary heart disease.CONCLUSION:Under standard medical treatment of diabetes,including the control of LDL cholesterol levels,the apoE4 isoform was not associated with coronary heart disease among T2DM patients.展开更多
Hepatocellular carcinoma(HCC) is one of the most prevalent malignancies worldwide and the second leading cause of death among all cancer types. Deregulation of the networks of tissue-specific transcription factors(TFs...Hepatocellular carcinoma(HCC) is one of the most prevalent malignancies worldwide and the second leading cause of death among all cancer types. Deregulation of the networks of tissue-specific transcription factors(TFs) observed in HCC leads to profound changes in the hepatic transcriptional program that facilitates tumor progression. In addition, recent reports suggest that substantial aberrations in the production of TF isoforms occur in HCC. In vitro experiments have identified distinct isoform-specific regulatory functions and related biological effects of liver-specific TFs that are implicated in carcinogenesis, which may be relevant for tumor progression and clinical outcome. This study reviews available data on the expression of isoforms of liver-specific and ubiquitous TFs in the liver and HCC and their effects, including HNF4α, C/EBPs, p73 and TCF7 L2, and indicates that assessment of the ratio of isoforms and targeting specific TF variants may be beneficial for the prognosis and treatment of HCC.展开更多
To identify the metabolite and CYP450 isoforms involved in rat liver microsomal metabolism of TM208. The present study investigated the metabolism of TM208 and the effects of selective CYP450 inhibitors on the metabol...To identify the metabolite and CYP450 isoforms involved in rat liver microsomal metabolism of TM208. The present study investigated the metabolism of TM208 and the effects of selective CYP450 inhibitors on the metabolism of TM208 in rat liver microsomes. Various specific inhibitors of CYP were used to identify the isoforms of CYP involved in the metabolism of TM208. The inhibitor of CYP2D and that of CYP2B had strong inhibitory effects on TM208 metabolism in a concentration-de- pendant manner, the inhibitor of CYP1A had a modest inhibitory effect, and the inhibitor of CYP3A seemed not to have an obvious inhibitory effect on TM208 metabolism. TM208 might mainly be metabolized by CYP2D and CYP2B in rat liver microsomes.展开更多
An early-maturity indica rice variety Zhefu 49, whose grain quality and starch structure are sensitive to environmental temperature, was subjected to different temperatures （32℃ for high temperature and 22℃ for opt...An early-maturity indica rice variety Zhefu 49, whose grain quality and starch structure are sensitive to environmental temperature, was subjected to different temperatures （32℃ for high temperature and 22℃ for optimum temperature） at the grain filling stage in plant growth chambers, and the different expressions of three isoform genes （SBEI, SBEIII and SBE/V） encoding starch branching enzyme （SBE） in the endosperms were studied by the real-time fluorescence quantitative PCR （FQ-PCR） method. Effects of high temperature on the SBE expression in developing rice endosperrns were isoform-dependent. High temperature significantly down-regulated the expressions of SBEI and SBEIII, while up-regulated the expression of SBEIV. Compared with SBEIV and SBEIII, the expression of SBEI gene in Zhefu 49 rice endosperms was more sensitive to temperature variation at the grain filling stage. This study indicates that changes in weather/climate conditions especially temperature stress influence rice grain formation and its quality as evidenced by isoform expression.展开更多
Background： To identify PTEN isoform and explore its potential role in tumor suppression. Methods： Western blotting, over-expression, shRNA mediated knocking-down, and bioinformatic analysis were used to identify PT...Background： To identify PTEN isoform and explore its potential role in tumor suppression. Methods： Western blotting, over-expression, shRNA mediated knocking-down, and bioinformatic analysis were used to identify PTEN isoform and test its effect on PI3K-Akt signaling pathway. Cell proliferation, apoptosis, and migration assays were used to test PTEN isoform＇s biological activities. Results： The PTEN isoform is about 15 kDa bigger than PTEN and its expression is dependent on PTEN status. Immunoprecipitation for PTEN isoform followed by screening with antibodies against ISG15, SUMO1/2/3, Ubiquitin, and Nedd8 showed the identified PTEN isoform is not a general proteinaceous post-translational modification. In addition, overexpression of PTEN cDNA in cells did not generate PTEN isoform whereas knocking-down of PTEN reduced the protein levels of both PTEN and PTEN isoform in a proportional manner. Analysis of PTEN DNA sequence disclosed an alternative translational starting code （CTG） upstream of canonical PTEN coding sequence. Expression of cloned PTEN isoform generated a protein with a size about 15 kDa bigger than PTEN and suppressed PI3K-Akt signaling pathway in cells. Overexpression of PTEN isoform also led to decrease in cell growth and enhanced serum starvation--and UV irradiation--induced apoptosis through activation of Caspase 3. Finally, expression of PTEN isoform inhibited cell migration in scratch assay. Conclusions： PTEN isoform has PTEN-Iike activity and might be a new tumor suppressor.展开更多
DNA double-stranded break(DSB)is one of the most catastrophic damages of genotoxic insult.Inappropriate repair of DNA DSBs results in the loss of genetic information,mutation,and the generation of harmful genomic rear...DNA double-stranded break(DSB)is one of the most catastrophic damages of genotoxic insult.Inappropriate repair of DNA DSBs results in the loss of genetic information,mutation,and the generation of harmful genomic rearrangements,which predisposes an organism to immunodeficiency,neurological damage,and cancer.The tumor repressor p53 plays a key role in DNA damage response,and has been found to be mutated in 50%of human cancer.p53,p63,and p73 are three members of the p53 gene family.Recent discoveries have shown that human p53 gene encodes at least 12 isoforms.Different p53 members and isoforms play various roles in orchestrating DNA damage response to maintain genomic integrity.This review briefly explores the functions of p53 and its isoforms in DNA DSB repair.展开更多
文摘AIM: To develop a PCR assay using mutant-specific primers to detect mutation of tyrosine-methionine-aspartate-aspartate (YMDD) motif of HBV to tyrosine-valine-aspartate-aspartate (YVDD) or tyrosine-isoleucine-aspartate-aspartate (YIDD).METHODS: Cloned wild-type and mutant HBV sequences were used as templates to test the sensitivity and specificity of the assay. A variety of primer construction, primer concentration, dNTP concentration, and annealing temperature of primers were systematically examined. Pair primers specifi c to rtL180M and rtM204V were selected for YVDD detection. Primer specif ic to rtM204I with an additional 3’-penultimate base mismatched to both the mutant and wild-type sequence was selected for YIDD detection. We applied this assay to study YMDD mutants in 28 chronic hepatitis B patients before and after lamivudine treatment.RESULTS: We could detect as little as 0.001%-0.00001% of mutant viruses coexisting in 108-109 copies of wild-type HBV using this assay. YMDD mutants were detected in 8 of 12 HBeAg-positive patients and 8 of 16 HBeAg-negative patients before lamivudine treatment. After treatment, two more patients in HBeAg-positive patients and seven more patients in HBeAg-negative patients developed YMDD mutations. CONCLUSION: We developed a highly sensitive and specifi c assay for detecting YMDD mutants. This assay can be applied to monitor chronic hepatitis B patients before and during lamivudine treatment.
基金supported by the National Key Research and Development Program of China(2022-24)National Natural Science Foundation of China(42025604,42376102)Fundamental Research Funds for the Central Universities。
文摘Ectothermic organisms may expand their thermal tolerance by producing multiple protein isoforms with differing thermal sensitivities.While such isoforms commonly originate from allelic variation at a single locus(allozymes)or from gene duplication that gives rise to paralogs with distinct thermal responses,this study investigated mRNA editing as an alternative,post-transcriptional mechanism for generating mRNA variants.Cytosolic malate dehydrogenase(cMDH)was examined in foot tissue of two congeners of the marine mussel genus Mytilus,which occupy different thermal environments.Multiple editing events were detected within the mRNA coding region in both species.Editing sites were species-specific,with no shared positions identified.In M.coruscus,editing occurred at 117,123,135,190,195,204,279,and 444,while in M.galloprovincialis,editing was detected at 216 and 597.Each species exhibited multiple edited mRNA variants,and these isoforms were associated with differential protein expression.These findings suggest that mRNA editing may contribute an additional layer of molecular variation.The generation of diverse mRNA isoforms from a single DNA coding sequence may enhance enzymatic flexibility across temperature ranges,supporting eurythermal physiological performance and mitigating thermal stress.Moreover,the presence of multiple edited transcripts within individual organisms raises important caveats about the limitations of approaches that deduce amino acid sequences or estimate adaptive variation solely from genomic data.
文摘Leaf acid phosphatase (APase) activities of 274 soybean genotypes were surveyed under field conditions with two levels of P supplies, and a nutrient solution culture experiment with eight selected genotypes was subsequently conducted under greenhouse conditions to further characterize APase activity and its isoform expression induced by P starvation. Results from the field experiment showed that there was a great genotypic variation for leaf APase activity among the tested soybean genotypes from different origins, and APase activity in many of the tested genotypes (about 60%) was generally increased in the treatment without P fertilizer addition. Results from the nutrient solution culture experiment showed that APase activity in all the eight tested genotypes was generally enhanced by P starvation. Six isoforms of APases were detected in isoelectric focusing gels with samples from both young and old leaves. The activity of all the six isoforms was increased by P starvation, but no new APase isoform was induced. Our results suggest that leaf APase activity could serve as an enzymatic indicator of P starvation for soybean; the increase in leaf APase activity under low P stress was mainly caused by the increase in the activity of existing isoforms but not by the induction of new isoforms.
文摘Objective: To investigate the role of PKC isoforms in the regulation of LPS-triggered tumoricidal activity in macrophages and further elucidate its signal mechanisms. Methods: Two macrophage cell lines (P388D1 and RAW264.7) were stimulated by LPS alone, or with long-term of PMA pretreatment. Then cytotoxicities to P815 cells (by MTT assay) and IL-1, TNF- (by ELISA) and nitric oxide (NO) production (by Griess reagent) in supernatants were measured. Western blot for PKC isoforms after long-term PMA pretreatment was analyzed. Results: RAW264.7 cells were stimulated with LPS to kill target tumor cells P815, whereas P388D1 cells failed to develop such an ability. Down-regulation of PKC isoforms by chronic treatment with PMA significantly inhibited the LPS-induced cytotoxicity in RAW264.7 cells. In unstimulated state, Western blotting with rabbit antiserum specific for the PKC, 1, 2, or showed all 5 isoforms were detected in P388D1 cells, while only PKC, PKC1 and PKC were detected in RAW264.7 cells. Exposure of the cells to long-term of PMA treatment significantly down-regulated the expression of PKC, PKC1 and PKC in RAW264.7 cells. But in P388D1 cells, although PKC, PKC and PKC were down-regulated, the expression of PKC1 and PKC2 could not be regulated. Comparing with LPS-induced IL-1, TNF- and NO production by the two macrophage cell lines, P388D1 failed to produce NO. In RAW264.7 cells, LPS-induced NO production and antitumor activity was attenuated by the addition of L-NAME, an iNOS inhibitor. Conclusion: The results indicated a critical role of PKC in LPS-induced antitumor activity and this cytotoxicity is mainly due to PKC- mediated NO production by RAW264.7 cells, but not a direct cytotoxic activity.
基金Supported by Special Project for Breeding and Cultivation of GMO Varieties of Ministry of Agriculture (2011ZX08001-001, 2011ZX08001-004)Major Science and Technology Program of Hunan, China (2011FJ1002-2)+1 种基金Natural Science Foundation of Hunan, China (09JJ3046 )Science and Technology Innovation Program of Hunan Academy of Agricultural Sciences (2009hnnkycx17)~~
文摘[Objective] This study aimed to analyze the effects of temperature on the expression of AGPase isoform genes in rice endosperm during milk stage. [Method] Different temperature treatments （33 and 25 ℃ of daily mean temperature for high and normal temperature treatments, respectively） and the real-time fluorescence quantitative PCR （ FQPCR） were used to analyze the expression patterns of seven isoforms （AGPS1, AGPS2a, AGPS2b, AGPL1, AGPL2, AGPL3 and AGPL4） of ADPglucose pyrophosphorylase （AGPase） which was the key enzyme in starch synthesis and metabolism in rice endosperm of two rice varieties Teqing and Thai Fragrant Rice. [Result] The AGPase isoforms AGPS2b, AGPL2 and AGPL3 had much higher expression than the other four isoforms, thus they were thought to be the main expression patterns of AGPase in rice endosperm. The relative expressions of AGPL2 was the highest among all the isoforms. The relative expressions of AGPS2b, AGPL2 and AGPL3 were higher in the normal temperature treatment than in the high temperature treatment in both rice varieties. The relative expression of the three enzyme genes in milk stages in Teqing was higher than those in Thai Fragrant Rice under different temperature treatments. [Conclusion] This study provides a theoretical basis for further use of molecular biology techniques to cultivate stable high-quality rice varieties.
文摘Complex genetic relationships between neurodegenerative disorders and neuropsychiatric symptoms have been shown, suggesting shared pathogenic mechanisms and emphasizing the potential for developing common therapeutic targets. Apolipoprotein E(APOE) genotypes and their corresponding protein(Apo E) isoforms may influence the biophysical properties of the cell membrane lipid bilayer. However, the role of APOE in central nervous system pathophysiology extended beyond its lipid transport function. In the present review article, we analyzed the links existing between APOE genotypes and the neurobiology of neuropsychiatric symptoms in neurodegenerative and vascular diseases. APOE genotypes(APOE ε2, APOE ε3, and APOE ε4) were implicated in common mechanisms underlying a wide spectrum of neurodegenerative diseases, including sporadic Alzheimer's disease, synucleinopathies such as Parkinson's disease and Lewy body disease, stroke, and traumatic brain injury. These shared pathways often involved neuroinflammation, abnormal protein accumulation, or responses to acute detrimental events. Across these conditions, APOE variants are believed to contribute to the modulation of inflammatory responses, the regulation of amyloid and tau pathology, as well as the clearance of proteins such as α-synuclein. The bidirectional interactions among Apo E, amyloid and mitochondrial metabolism, immunomodulatory effects, neuronal repair, and remodeling underscored the complexity of Apo E's role in neuropsychiatric symptoms associated with these conditions since from early phases of cognitive impairment such as mild cognitive impairment and mild behavioral impairment. Besides Apo E-specific isoforms' link to increased neuropsychiatric symptoms in Alzheimer's disease(depression, psychosis, aberrant motor behaviors, and anxiety, not apathy), the APOE ε4 genotype was also considered a significant genetic risk factor for Lewy body disease and its worse cognitive outcomes. Conversely, the APOE ε2 variant has been observed not to exert a protective effect equally in all neurodegenerative diseases. Specifically, in Lewy body disease, this variant may delay disease onset, paralleling its protective role in Alzheimer's disease, although its role in frontotemporal dementia is uncertain. The APOE ε4 genotype has been associated with adverse cognitive outcomes across other various neurodegenerative conditions. In Parkinson's disease, the APOE ε4 allele significantly impacted cognitive performance, increasing the risk of developing dementia, even in cases of pure synucleinopathies with minimal co-pathology from Alzheimer's disease. Similarly, in traumatic brain injury, recovery rates varied, with APOE ε4 carriers demonstrating a greater risk of poor long-term cognitive outcomes and elevated levels of neuropsychiatric symptoms. Furthermore, APOE ε4 influenced the age of onset and severity of stroke, as well as the likelihood of developing stroke-associated dementia, potentially due to its role in compromising endothelial integrity and promoting blood–brain barrier dysfunction.
文摘Aim: To investigate the androgen receptor (AR) isoforms and its variability of expression in human and rat prostatictissues. Methods: Human benign prostatic hyperplasia (BPH) and prostatic cancer tissues were obtained from pa-tients undergoing prostatectomy, and rat ventral prostate was incised 3 days after castration. Forty-one AR-positive BPHspecimens, 3 prostatic cancer specimens, and 6 rat prostates were used. After processing at 4℃, the tissues were ex-amined by means of high resolution isoelectric focusing (IEF) technique to determine their AR isoforms. Results:From the prostatic specimens, 3 types of AR isoforms were detected with pI values at 6.5, 6.0, and 5.3. In humanBPH tissues, 15/41 (36.6%) specimens showed all the three types of isoforms, while 19/41 (46.3%) showed 2 iso-fora at various combinations and 7/41 (17.1%), 1 isoform. For the 3 prostatic cancer specimens, one showed 3 iso-forms, one, 2 isoforms, and the other failed to show any isoform. All rat prostatic tissues showed 2 isoforms at differ-ent combinations. Binding of ~3H-dihydrotestosterone (DHT) to the isoforms was inhibited by the addition of 100-foldexcess of DHT or testosterone, but not progesterone, oestradiol or diethylstilboestrol. Conclusion: AR isoforms aredifferent in different patients. Although their genesis is not clear, the therapeutic implication of the present observationappears to be interesting, that may help clarifying the individual differences in the response to hormonal therapy.(Asian J Androl 2000 Dec; 2: 307-310)
基金Supported by Cancer projects in the C télab are funded through the Cancer Research Society,Canadian Research Institutes of Health Research and Canadian Breast Cancer Foundation
文摘Protein arginine methyltransferases(PRMTs) catalyze the methylation of a variety of protein substrates, many of which have been linked to the development, progression and aggressiveness of different types of cancer. Moreover, aberrant expression of PRMTs has been observed in several cancer types. While the link between PRMTs and cancer is a relatively new area of interest, the functional implications documented thus far warrant further investigations into its therapeutic potential. However, the expression of these enzymes and the regulation of their activity in cancer are still significantly understudied. Currently there are nine main members of the PRMT family. Further, the existence of alternatively spliced isoforms for several of these family members provides an additional layer of complexity. Specifically, PRMT1, PRMT2, CARM1 and PRMT7 have been shown to have alternative isoforms and others may be currently unrealized. Our knowledge with respect to the relative expression and the specific functions of these isoforms is largely lacking and needs attention. Here we present a review of the current knowledge of theknown alternative PRMT isoforms and provide a rationale for how they may impact on cancer and represent potentially useful targets for the development of novel therapeutic strategies.
基金The National High Technology Research and Development Program(863 Program)of China under contract No.2012AA092205the Major State Basic Research Development Program(973 Program)of China under contract No.2012CB114403+2 种基金the China Agriculture Research System-47the National Natural Science Foundation of China under contract No.31472297 and 31302209the Scientific Research Foundation of Third Institute of Oceanography,SOA under contract No.2011018
文摘In this study, the gene encoding hemocyanin subunit L, Lv Hc L, was cloned from Litopenaeus vannamei and the genomic organization was characterized. This gene was diverse with many SNPs and also had at least four isoforms, while one of them（Lv Hc L4） only had two exons and the exon2 was missed. Transcription analysis showed that these isoforms of Lv Hc L were up-regulated after WSSV challenge in WSSV-resistant shrimp, while the transcriptions were decreased constantly in WSSV-susceptible shrimp. It is suggested that the hemocyanin had rich polymorphism and was involved in the antiviral response. These results could extend our previous findings and provide insights into the immune feature of hemocyanin, which would be helpful for further studies aimed at antiviral mechanism in invertebrate.
文摘AIM:To investigate three isoforms of survivin in colorectal adenocarcinomas.METHODS:We used the LightCycler Technology(Roche),along with a common forward primer and reverse primers specific for the splice variants and two common hybridization probes labeled with fluorescein and LightCycler-Red fluorophore(LC-Red 640).Real time quantitative polymerase chain reaction(PCR) was performed on cDNAs from 52 tumor specimens from colorectal cancer patients and 10 unrelated normal colorectal tissues.In the patients group,carcinoembryonic antigen(CEA) and CA19-9 tumor markers were also measured immunochemically.RESULTS:Wild type survivin mRNA isoform was expressed in 48%of the 52 tumor samples,survivin-2b in 38%and survivin-ΔΕx3 in 29%,while no expression was found in normal tissues.The mRNA expression of wild type survivin presented a significant correlation with the expression of the ratio of survivin-2b,survivin-ΔΕx3,survivin-2b/wild type survivin and survivin-ΔΕx3/wild type survivin(P<0.001).The mRNA expression of wildsurvivin and survivin-ΔΕx3 was related with tumor size and invasion(P=0.006 and P<0.005,respectively).A significant difference was found between survivin-2b and morphologic cancer type.Also,the ratio of survivin-ΔEx3/ wild-survivin was significantly associated with prognosis.No association was observed between the three isoforms and grade,metastasis,Dukes stage and gender.The three isoforms were not correlated with CEA and CA19-9.CONCLUSION:Survivin isoforms may play a role in cell apoptosis and their quantification could provide information about clinical management of patients suffering from colorectal cancer.
文摘Nitrogen is a key element to control the growth and yield of crops. Fertilizer urea nitrogen (N) 60,45, and 30 kg/hm2 was applied at three different stages, midtillering, panicle initiation, and flowering, of the growth and development of rice plants, respectively. At both midtillering and panicle initiation, the total activity of glutamine synthetase (GS) in rice roots and leaves was incrased remarkably as a result of a large amount of ammonia absorbed by roots. Native-PAGE and activity staining showed that the increase of total activity in rice roots and leaves was due to the synthesis of GSrb in roots and GS2 in leaves and that the activity of GSra in roots and GS1 in leaves remained constant. The results showed that the assimilation of external nitrogen was carried out by GSrb but not GSra in rice roots and that the activitry of GS2 was induced also by the external nitrogen, and that GSrb played main role in meeting the needs of the rapid tillering for nitrogen. At flowering, the activity of GS in rice roots and leaves did not change almost after topdressing. These rssults suggest that the change of GS activity in rice roots may use as a measure of the utilization efficiency of the fertilizer.
基金Supported by Shandong Provincial Award Foundation for Youth and Middle-aged Scientist,No.BS2010SW034
文摘AIM To investigate the role of Δ133p53 isoform in nuclear factor-κB(NF-κB) inhibitor pyrrolidine dithiocarbamate(PDTC)-mediated growth inhibition of MKN45 gastric cancer cells.METHODS The growth rate of MKN45 cells after treatment with different concentrations of only PDTC or PTDC in combination with cisplatin was detected by the CCK-8 assay. m RNA expression levels of Δ133p53, p53β, and the NF-κB p65 subunit and p65 protein levels were detected by reverse transcription-polymerase chain reaction(RT-PCR) and immunofluorescence, respectively. Growth of MKN45 cells was significantly inhibited by PDTC alone in a dose-dependent manner(P < 0.01). Moreover, the inhibitory effect of cisplatin was remarkably enhanced in a dose-dependent manner by co-treatment with PDTC(P < 0.01).RESULTS RT-PCR analysis revealed that m RNA expression of p65 was curbed significantly in a dose-dependent manner by treatment with only PDTC(P < 0.01), and this suppressive effect was further enhanced when co-treated with cisplatin(P < 0.01). With respect to the other p53 isoforms, m RNA level of Δ133p53 was significantly reduced in a dose-dependent manner by treatment with only PDTC or PTDC in combination with cisplatin(P < 0.01), whereas p53β m RNA expression was not altered by PDTC treatment(P > 0.05). A similar tendency of change in p65 protein expression, as observed for the corresponding m RNA, was detected by immunofluorescence analysis(P < 0.01). Pearson correlation analysis demonstrated that Δ133p53 and p65 m RNA expression levels were positively related, while no significant relationship was observed between those of p65 and p53β(r = 0.076, P > 0.01).CONCLUSIONΔ133p53 isoform(not p53β) is required in PDTCinduced inhibition of MKN45 gastric cancer cells, indicating that disturbance in the cross-talk between p53 and NF-κB pathways is a promising target in pharmaceutical research for the development of treatment strategies for gastric cancer.
文摘AIM:To analyze the risk of coronary heart disease in patients with type 2 diabetes mellitus(T2DM)receiving standard medical treatment.METHODS:We performed a retrospective chart analysis of 269 middle-aged patients(age 45-64 years,mean age,53.9±5.5 years)with T2DM and without atherosclerotic cardiovascular events who underwent typing to determine their apolipoprotein E(apoE)isoforms.The apoE isoforms were determined using isoelectric focusing,followed by immunoblotting.We retrospectively evaluated the charts of the 269 patients,recorded between their first visit to the hospital(the study's start point,between 1987 and 1992)and the occurrence of an atherosclerotic cardiovascular event(the study's endpoint)or January 2004,whichever came first.The age-adjusted mean values and the prevalences of covariates were calculated to compare the laboratory data among the apoE phenotypes.To investigate the association of risk factors with the incidence of coronary heart disease during the follow-up period,monovariate and multivariate Cox regression models were used.RESULTS:At enrollment,the mean serum low density lipoprotein(LDL)cholesterol levels were lowest(2.92± 0.89 mmol/L)among the subjects with apoE2(apoE2/2 or apoE2/3)and highest(3.52±0.77 mmol/L)among the subjects with apoE4(apoE3/4 or apoE4/4).No significant differences in mean age or the percentage of smokers were observed among the three groups.Furthermore,no significant differences were observed in the systolic and diastolic blood pressures,body mass index,HbA1c level or serum triglyceride levels among the three groups.There were 47 cases of coronary heart disease over 3285 person-years of follow-up.An age-adjusted multivariate Cox proportional model identified diabetic retinopathy(hazard ratio,2.38,95% CI:1.28-4.43,P=0.006),a high systolic blood pressure(hazard ratio,1.04,95%CI:1.02-1.06,P<0.001) and high HbA1c values(hazard ratio,1.19,95%CI:1.02-1.38,P=0.0029),but not the LDL cholesterol value at enrollment(hazard ratio,1.01,95%CI:0.97-1.05,P=0.77)nor the specific apoE isoform,as significant predictors of coronary heart disease.CONCLUSION:Under standard medical treatment of diabetes,including the control of LDL cholesterol levels,the apoE4 isoform was not associated with coronary heart disease among T2DM patients.
基金Supported by Russian Foundation for Basic Research,contract No.18-34-00816\18
文摘Hepatocellular carcinoma(HCC) is one of the most prevalent malignancies worldwide and the second leading cause of death among all cancer types. Deregulation of the networks of tissue-specific transcription factors(TFs) observed in HCC leads to profound changes in the hepatic transcriptional program that facilitates tumor progression. In addition, recent reports suggest that substantial aberrations in the production of TF isoforms occur in HCC. In vitro experiments have identified distinct isoform-specific regulatory functions and related biological effects of liver-specific TFs that are implicated in carcinogenesis, which may be relevant for tumor progression and clinical outcome. This study reviews available data on the expression of isoforms of liver-specific and ubiquitous TFs in the liver and HCC and their effects, including HNF4α, C/EBPs, p73 and TCF7 L2, and indicates that assessment of the ratio of isoforms and targeting specific TF variants may be beneficial for the prognosis and treatment of HCC.
基金National Basic Research Program of China (863 Program,Grant No.2004AA2Z3783)National Natural Science Foundation of China (Grant No.20672009)
文摘To identify the metabolite and CYP450 isoforms involved in rat liver microsomal metabolism of TM208. The present study investigated the metabolism of TM208 and the effects of selective CYP450 inhibitors on the metabolism of TM208 in rat liver microsomes. Various specific inhibitors of CYP were used to identify the isoforms of CYP involved in the metabolism of TM208. The inhibitor of CYP2D and that of CYP2B had strong inhibitory effects on TM208 metabolism in a concentration-de- pendant manner, the inhibitor of CYP1A had a modest inhibitory effect, and the inhibitor of CYP3A seemed not to have an obvious inhibitory effect on TM208 metabolism. TM208 might mainly be metabolized by CYP2D and CYP2B in rat liver microsomes.
文摘An early-maturity indica rice variety Zhefu 49, whose grain quality and starch structure are sensitive to environmental temperature, was subjected to different temperatures （32℃ for high temperature and 22℃ for optimum temperature） at the grain filling stage in plant growth chambers, and the different expressions of three isoform genes （SBEI, SBEIII and SBE/V） encoding starch branching enzyme （SBE） in the endosperms were studied by the real-time fluorescence quantitative PCR （FQ-PCR） method. Effects of high temperature on the SBE expression in developing rice endosperrns were isoform-dependent. High temperature significantly down-regulated the expressions of SBEI and SBEIII, while up-regulated the expression of SBEIV. Compared with SBEIV and SBEIII, the expression of SBEI gene in Zhefu 49 rice endosperms was more sensitive to temperature variation at the grain filling stage. This study indicates that changes in weather/climate conditions especially temperature stress influence rice grain formation and its quality as evidenced by isoform expression.
基金Advanced key Scientific and Technological Programs of Ningbo(2013C51009)National Natural Science Foundation of China(31271451)
文摘Background： To identify PTEN isoform and explore its potential role in tumor suppression. Methods： Western blotting, over-expression, shRNA mediated knocking-down, and bioinformatic analysis were used to identify PTEN isoform and test its effect on PI3K-Akt signaling pathway. Cell proliferation, apoptosis, and migration assays were used to test PTEN isoform＇s biological activities. Results： The PTEN isoform is about 15 kDa bigger than PTEN and its expression is dependent on PTEN status. Immunoprecipitation for PTEN isoform followed by screening with antibodies against ISG15, SUMO1/2/3, Ubiquitin, and Nedd8 showed the identified PTEN isoform is not a general proteinaceous post-translational modification. In addition, overexpression of PTEN cDNA in cells did not generate PTEN isoform whereas knocking-down of PTEN reduced the protein levels of both PTEN and PTEN isoform in a proportional manner. Analysis of PTEN DNA sequence disclosed an alternative translational starting code （CTG） upstream of canonical PTEN coding sequence. Expression of cloned PTEN isoform generated a protein with a size about 15 kDa bigger than PTEN and suppressed PI3K-Akt signaling pathway in cells. Overexpression of PTEN isoform also led to decrease in cell growth and enhanced serum starvation--and UV irradiation--induced apoptosis through activation of Caspase 3. Finally, expression of PTEN isoform inhibited cell migration in scratch assay. Conclusions： PTEN isoform has PTEN-Iike activity and might be a new tumor suppressor.
基金supported by the National Natural Science Foundation of China(Nos.31571511 and 31871500)
文摘DNA double-stranded break(DSB)is one of the most catastrophic damages of genotoxic insult.Inappropriate repair of DNA DSBs results in the loss of genetic information,mutation,and the generation of harmful genomic rearrangements,which predisposes an organism to immunodeficiency,neurological damage,and cancer.The tumor repressor p53 plays a key role in DNA damage response,and has been found to be mutated in 50%of human cancer.p53,p63,and p73 are three members of the p53 gene family.Recent discoveries have shown that human p53 gene encodes at least 12 isoforms.Different p53 members and isoforms play various roles in orchestrating DNA damage response to maintain genomic integrity.This review briefly explores the functions of p53 and its isoforms in DNA DSB repair.
