Previous work from this laboratory has demonstrated that the induction of c-fos by angiotensin (Ang) Ⅱ in vascular smooth muscle cells (VSMC) is mediated by at least two enhancer elements, the serum response element ...Previous work from this laboratory has demonstrated that the induction of c-fos by angiotensin (Ang) Ⅱ in vascular smooth muscle cells (VSMC) is mediated by at least two enhancer elements, the serum response element (SRE) and the cyclic AMP response element (CRE). These two elements appear to act independently and equally. The current study is aimed at identifying the trans-acting proteins that interact with these enhancer ele-.ments to mediate this response. Rat aortic smooth muscle (RASM) cells were grown in culture and made quiescent by placing them in a defined serum-free media for 48 hours.Aug Ⅱor vehicle was then added, the cells harvested 30 minutes later and nuclear extracts isolated. Gel mobility shift assay were then performed.gel shifts done with wild type SRE oligonucleotide demonstrated that two specific proteins bound to this element.Mutations in central CArG box of the SRE inhibited binding but mutations in the ets binding site in the SRE had no effect. Extracts from Aug Ⅱor vehicle treated cells demonstrated an identical pattern of binding. Similar experiments performed with CRE noligonucleotide identified three proteins which bound to CRE. Again,no differences were observed between vehicle and AugⅡtreated extracts. An antibody to serum response factor(SRF),which binds to the SRE, supershifted the proteins that bound to the SRE. When gel shifts with RASM cells extracts were compared to gel shifts from either NIH 3T3 fibroblast cell extraes of HeLa cell extracts,a different pattern of protein binding was observed using the SRE oligonucleotide.In contrast to the studies with the SRF antibody,an antibody to CRE binding protein (CREB)-43, the most common CREB protein, failed to recognize protein from RASM extract in a supershift assay. When the gel shift pattern with the CRE oligonucleotide between RASM, 3T3 and HeLa cell extracts was compared,no similarity was seen. Taken together,'these data suggest that stimulation of c-for in VSMC's occurs via activation of a unique set of proteins. Activation of these proteins is not due to new protein synthesis. Further work will be aimed at identifying these proteins and studying their mechanism of activation in VSMC's.展开更多
Objective To investigate the effect of trans-acting factor(s) on rat glutathione S-transferase P1 gene (rGSTP1) transcription regulation in tumor cells.Methods The binding of trans-acting factor(s) to two enhancers...Objective To investigate the effect of trans-acting factor(s) on rat glutathione S-transferase P1 gene (rGSTP1) transcription regulation in tumor cells.Methods The binding of trans-acting factor(s) to two enhancers of the rGSTP1 gene, glutathione S-transferase P enhancer Ⅰ (GPEI) and glutathione S-transferase P enhancer Ⅱ-1 (GPEⅡ-1), was identified by an electrophoretic mobility shift assay (EMSA). The molecular weight of trans-acting factor was measured in a UV cross-linking experiment. Results Trans-acting factor interacting with the core sequence of GPEI (cGPEI) were found in human cervical adenocarcinoma cell line (HeLa) and rat hepatoma cell line (CBRH7919). These proteins were not expressed in normal rat liver. Although specific binding proteins that bound to GPEⅡ-1 were detected in all three cell types, a 64 kDa binding protein that exists in HeLa and CBRH7919 cells was absent in normal rat liver. Conclusion cGPEI, GPEII specific binding proteins expressed in HeLa and CBRH7919 cells may play an important role in the high transcriptional level of the rGSTP1 gene in tumor cells.展开更多
To establish a cytologic expressing system of rat glutathione S-transferase pi (GST-pi) cDNA for detecting the resistance of HeLa cells to anticancer drugs. Methods The assessment was made with various anticancer dr...To establish a cytologic expressing system of rat glutathione S-transferase pi (GST-pi) cDNA for detecting the resistance of HeLa cells to anticancer drugs. Methods The assessment was made with various anticancer drugs (adriamycin, mitomycin, cisplatinum and vincristine) that showed different cytotoxicities in transfectant HeLa cells with pSV-GT containing rat GST-pi cDNA (HeLa/pSV-GT) or control pSV-neo (HeLa/pSV-neo). Expression levels of GST-pi mRNA in HeLa/pSV-GT and HeLa/pSV-neo were measured by in situ hybridization using Digoxin-labelled cDNA probe. Results HeLa/pSV-GT expressed significantly high degree of GST-pi mRNA, whereas both HeLa/pSV-neo and HeLa cells had very low expression. Cytotoxicities of HeLa/pSV-GT and HeLa/pSV-neo with 4 anticancer drugs were measured by MTT assay. Drug concentrations for yielding 50% inhibition (IC50) in HeLa/pSV-GT by adriamycin, mitomycin and cisplatinum were 70.13 靏/mL, 10.95 靏/mL and 16.52 靏/mL, respectively. In contrast, IC50 in HeLa/pSV-neo was 10.34 靏/mL, 7.48 靏/mL and 13.70 靏/mL, respectively. The cytotoxicities of vincristine on both HeLa/pSV-GT and HeLa/pSV-neo were not significantly different. Conclusions Our findings suggest that HeLa/pSV-GT containing rat GST-pi cDNA is resistant to some anticancer drugs due to overexpression of GST-pi. Also, HeLa/pSV-GT cell line could serve as a useful cytogenetic model for further research.展开更多
The erythroid- and developmental stage-specific expression of the human ε-globin gene is controlled, in part,by the 5’-flanking DNA sequence of this gene. In the present study, we have used DNA-protein binding assay...The erythroid- and developmental stage-specific expression of the human ε-globin gene is controlled, in part,by the 5’-flanking DNA sequence of this gene. In the present study, we have used DNA-protein binding assays to identify trans-acting factors which regulate the temporal expression of the human ε-globin gene during development. Using gel mobility shift assays and DNasel footprinting assays, a nuclear protein factor (termed ε-SSF1) in the nuclear extracts from mouse haematopoietic tissues at d 11 and d 13 of gestation was identified. It could specifically bind to the positive control region (between -535 and -453bp) of the human ε-globin gene. We speculated that the E-SSF1 might be an erythroid- and developmental stage-specific activator. In addition, we found another nuclear protein factor (termed ε-R1) in the nuclear extract from mouse fetal liver at d 18 of gestation, which could strongly bind to the silencer region (between -392 and -177bp) of this gene. Therefore, we speculated that the ε-R1 might be an erythroid- and developmental stagespecific repressor. Our data suggest that both ε-SSF1 and ε-R1 might play important roles in developmental regulation of the human ε-globin gene expression during the early embryonic life. On the other hand, we observed that the binding patterns of nuclear proteins from three cell lines (K562, HEL and Raji) to these regulatory regions were partially different. These results suggest that different trans-acting factors in K562, HEL and Raji cells might be responsible for activating or silencing the human ε-globin gene in three different cell lines.展开更多
The DNasel hypersensitive site 2 (HS2) of human β-globin locus control region (LCR) is required fOr the high level expression of human d-globin genes. In the present study, a stage-specific protein factor (LPF-β) wa...The DNasel hypersensitive site 2 (HS2) of human β-globin locus control region (LCR) is required fOr the high level expression of human d-globin genes. In the present study, a stage-specific protein factor (LPF-β) was identified in the nuclear extract prepared from mouse fetal liver at d 18 of gestation, which could bind to the HS2 region of humanβ-globin LCRt We also found that the shift band of LPF-βfactor could be competed by humanβ-globin promoter. However, it couldn’t be competed by human E-globin promoter or by human Aβ-globin promoter. Furthermore, our data demonstrated that the binding-sequence of LPF-d factor is 5’CACACCCTA 3’,which is located at the HS2 region ofβ-LCR (from -10845 to -10853 bp) and humanβ-globin promoter (from -92 to -84 bp). We speculated that these regions containing the CACCC box in both the humallβ-globin promoter and HS2 might function as stage selector elements in the regulation of humanβd-globin switching and the LPF-βfactor might be a stage-specific protein factor involved in the regulation of humanβ-globin gene expression.展开更多
In order to elucidate the molecular mechanisms of globin gene expression during embryonic development, the nuclear extracts from mouse hematopoietic tissue at different stages of development have been prepared. By usi...In order to elucidate the molecular mechanisms of globin gene expression during embryonic development, the nuclear extracts from mouse hematopoietic tissue at different stages of development have been prepared. By using DNase I footprinting and gel mobility shift assays, the binding of protein factors in these extracts to the human βglobin promoter was analyzed. The differences in the binding patterns of protein factors during development were observed. An erythroid-specific and stage-specific nuclear protein in the nuclear extract from d 18 mouse fetal liver was identified, which can bind to the sequence (from -66bp to -90bp) of human β-globin promoter. We therefore speculate that the function of this cis-acting element may be similar to stage selector element (SSE) in chieken βA- promoter.展开更多
There was a bi-directional promoter between gene 38 kd phosphorylated protein (pp38) gene; 1.8-kb mRNA transcript gene family in the genome of Marek's disease virus (MDV). In this study, enhanced green fluorescenc...There was a bi-directional promoter between gene 38 kd phosphorylated protein (pp38) gene; 1.8-kb mRNA transcript gene family in the genome of Marek's disease virus (MDV). In this study, enhanced green fluorescence protein (EGFP) reporter plamids, pP(pp38)-EGFP; pP(1.8-kb)-EGFP, were constructed under this bi-directional promoter in two directions. The two plasmids were transfected into uninfected chicken embryo fibroblast (CEF), MDV clone rMd5 infected CEF (rMd5-CEF); pp38-deleted derivative rMd5Δpp38 infected CEF (rMd5Δpp38-CEF) respectively. Transfection analysis showed that EGFP was only expressed in rMd5-CEF,; no EGFP could be detected in uninfected CEF or rMd5Δpp38-CEF, implying that pp38 was a factor influencing the activity of the promoter. The pp38-expressing recombinant plasmid pcDNA-pp38 was constructed to co-transfect CEF or rMd5Δpp38-CEF with pP(pp38)-EGFP or pP(1.8-kb)-EGFP. In this case, EGFP could be detected only in rMd5Δpp38-CEF but still not in uninfected CEF, implying that pp38 needs other protein(s) to work together for the complete trans-acting activity. Another MDV gene, 24 kd phosphorylated protein pp24 gene was cloned into pcDNA3.1 as a pp24-expressing recombinant plasmid pcDNA-pp24. When uninfected CEF was co-transfected with pcDNA-pp38, pcDNA-pp24; EGFP expressing plasmids pP(pp38)-EGFP or pP(1.8-kb)-EGFP, the EGFP could be detected. These results indicated that pp38; pp24 could enhance the activity of the promoter when they worked together. DNA mobility shift assay showed that pp38 would bind to the bi-directional promoter with the co-existing of pp24, although neither of them alone influenced mobility of the promoter DNA. All the above suggested that MDV pp38 could transactivate the bi-directional promoter when combined with pp24. The results also indicated that the activity of the promoter in the direction of 1.8-kb mRNA was significantly stronger than that of pp38 direction.展开更多
The two LIM domain-containing proteins from plants （LIMs） typically exhibit a dual cytoplasmic-nuclear dis-tribution, suggesting that, in addition to their previously described roles in actin cytoskeleton organizati...The two LIM domain-containing proteins from plants （LIMs） typically exhibit a dual cytoplasmic-nuclear dis-tribution, suggesting that, in addition to their previously described roles in actin cytoskeleton organization, they partici-pate in nuclear processes. Using a south-western blot-based screen aimed at identifying factors that bind to plant histone gene promoters, we isolated a positive clone containing the tobacco LIM protein WLIM2 （NtWLIM2） cDNA. Using both green fluorescent protein （GFP） fusion-and immunology-based strategies, we provide clear evidence that NtWLIM2 local-izes to the actin cytoskeleton, the nucleus, and the nucleolus. Interestingly, the disruption of the actin cytoskeleton by latrunculin B significantly increases NtWLIM2 nuclear fraction, pinpointing a possible novel cytoskeletal-nuclear crosstalk. Biochemical and electron microscopy experiments reveal the ability of NtWLIM2 to directly bind to actin filaments and to crosslink the latter into thick actin bundles. Electrophoretic mobility shift assays show that NtWLIM2 specifically binds to the conserved octameric cis-elements （Oct） of the Arabidopsis histone H4A748 gene promoter and that this binding largely relies on both LIM domains. Importantly, reporter-based experiments conducted in Arabidopsis and tobacco proto-plasts confirm the ability of NtWLIM2 to bind to and activate the H4A748 gene promoter in live cells. Expression studies indicate the constitutive presence of NtWLIM2 mRNA and NtWLIM2 protein during tobacco BY-2 cell proliferation and cell cycle progression, suggesting a role of NtWLIM2 in the activation of basal histone gene expression. Interestingly, both live cell and in vitro data support NtWLIM2 di/oligomerization. We propose that NtWLIM2 functions as an actin-stabilizing protein, which, upon cytoskeleton remodeling, shuttles to the nucleus in order to modify gene expression.展开更多
The human ε-globin gene is expressed in a tissue-specific and developmental stage-specific manner. During the earliest stage of gestation, this gene is expressed in the yolksac, but is silenced completely at the 6th-...The human ε-globin gene is expressed in a tissue-specific and developmental stage-specific manner. During the earliest stage of gestation, this gene is expressed in the yolksac, but is silenced completely at the 6th-8th weeks of gestation. Recently, several studieson the transgenic mice have shown that the 5′-flanking DNA sequences of human展开更多
Hybrids are always a focus of botanical research and have a high practical value in agricultural production.To better understand allele regulation and differences in DNA methylation in hybrids,we developed a phasing p...Hybrids are always a focus of botanical research and have a high practical value in agricultural production.To better understand allele regulation and differences in DNA methylation in hybrids,we developed a phasing pipeline for hybrid rice based on two parental genomes(PP2PG),which is applicable for Iso-Seq,RNA-Seq,and Bisulfite sequencing(BS-Seq).Using PP2PG,we analyzed differences in gene transcription,alternative splicing,and DNA methylation in an allele-specific manner between parents and progeny or different progeny alleles.The phasing of Iso-Seq data provided a great advantage in separating the whole gene structure and producing a significantly higher separation ratio than RNA-Seq.The interaction of hybrid alleles was studied by constructing an allele co-expression network that revealed the dominant allele effect in the network.The expression variation between parents and the parental alleles in progeny showed tissue-or environment-specific patterns,which implied a preference for trans-acting regulation under different conditions.In addition,by comparing allele-specific DNA methylation,we found that CG methylation was more likely to be inherited than CHG and CHHmethylation,and its enrichment in genic regions was connected to gene structure.In addition to an effective phasing pipeline,we also identified differentiation in OsWAK38 gene structure that may have led to the expansion of allele functions in hybrids.In summary,we developed a phasing pipeline and provided valuable insights into alternative splicing,interaction networks,trans-acting regulation,and the inheritance of DNA methylation in hybrid rice.展开更多
文摘Previous work from this laboratory has demonstrated that the induction of c-fos by angiotensin (Ang) Ⅱ in vascular smooth muscle cells (VSMC) is mediated by at least two enhancer elements, the serum response element (SRE) and the cyclic AMP response element (CRE). These two elements appear to act independently and equally. The current study is aimed at identifying the trans-acting proteins that interact with these enhancer ele-.ments to mediate this response. Rat aortic smooth muscle (RASM) cells were grown in culture and made quiescent by placing them in a defined serum-free media for 48 hours.Aug Ⅱor vehicle was then added, the cells harvested 30 minutes later and nuclear extracts isolated. Gel mobility shift assay were then performed.gel shifts done with wild type SRE oligonucleotide demonstrated that two specific proteins bound to this element.Mutations in central CArG box of the SRE inhibited binding but mutations in the ets binding site in the SRE had no effect. Extracts from Aug Ⅱor vehicle treated cells demonstrated an identical pattern of binding. Similar experiments performed with CRE noligonucleotide identified three proteins which bound to CRE. Again,no differences were observed between vehicle and AugⅡtreated extracts. An antibody to serum response factor(SRF),which binds to the SRE, supershifted the proteins that bound to the SRE. When gel shifts with RASM cells extracts were compared to gel shifts from either NIH 3T3 fibroblast cell extraes of HeLa cell extracts,a different pattern of protein binding was observed using the SRE oligonucleotide.In contrast to the studies with the SRF antibody,an antibody to CRE binding protein (CREB)-43, the most common CREB protein, failed to recognize protein from RASM extract in a supershift assay. When the gel shift pattern with the CRE oligonucleotide between RASM, 3T3 and HeLa cell extracts was compared,no similarity was seen. Taken together,'these data suggest that stimulation of c-for in VSMC's occurs via activation of a unique set of proteins. Activation of these proteins is not due to new protein synthesis. Further work will be aimed at identifying these proteins and studying their mechanism of activation in VSMC's.
文摘Objective To investigate the effect of trans-acting factor(s) on rat glutathione S-transferase P1 gene (rGSTP1) transcription regulation in tumor cells.Methods The binding of trans-acting factor(s) to two enhancers of the rGSTP1 gene, glutathione S-transferase P enhancer Ⅰ (GPEI) and glutathione S-transferase P enhancer Ⅱ-1 (GPEⅡ-1), was identified by an electrophoretic mobility shift assay (EMSA). The molecular weight of trans-acting factor was measured in a UV cross-linking experiment. Results Trans-acting factor interacting with the core sequence of GPEI (cGPEI) were found in human cervical adenocarcinoma cell line (HeLa) and rat hepatoma cell line (CBRH7919). These proteins were not expressed in normal rat liver. Although specific binding proteins that bound to GPEⅡ-1 were detected in all three cell types, a 64 kDa binding protein that exists in HeLa and CBRH7919 cells was absent in normal rat liver. Conclusion cGPEI, GPEII specific binding proteins expressed in HeLa and CBRH7919 cells may play an important role in the high transcriptional level of the rGSTP1 gene in tumor cells.
基金the National Natural Science Foundation of China.
文摘To establish a cytologic expressing system of rat glutathione S-transferase pi (GST-pi) cDNA for detecting the resistance of HeLa cells to anticancer drugs. Methods The assessment was made with various anticancer drugs (adriamycin, mitomycin, cisplatinum and vincristine) that showed different cytotoxicities in transfectant HeLa cells with pSV-GT containing rat GST-pi cDNA (HeLa/pSV-GT) or control pSV-neo (HeLa/pSV-neo). Expression levels of GST-pi mRNA in HeLa/pSV-GT and HeLa/pSV-neo were measured by in situ hybridization using Digoxin-labelled cDNA probe. Results HeLa/pSV-GT expressed significantly high degree of GST-pi mRNA, whereas both HeLa/pSV-neo and HeLa cells had very low expression. Cytotoxicities of HeLa/pSV-GT and HeLa/pSV-neo with 4 anticancer drugs were measured by MTT assay. Drug concentrations for yielding 50% inhibition (IC50) in HeLa/pSV-GT by adriamycin, mitomycin and cisplatinum were 70.13 靏/mL, 10.95 靏/mL and 16.52 靏/mL, respectively. In contrast, IC50 in HeLa/pSV-neo was 10.34 靏/mL, 7.48 靏/mL and 13.70 靏/mL, respectively. The cytotoxicities of vincristine on both HeLa/pSV-GT and HeLa/pSV-neo were not significantly different. Conclusions Our findings suggest that HeLa/pSV-GT containing rat GST-pi cDNA is resistant to some anticancer drugs due to overexpression of GST-pi. Also, HeLa/pSV-GT cell line could serve as a useful cytogenetic model for further research.
文摘The erythroid- and developmental stage-specific expression of the human ε-globin gene is controlled, in part,by the 5’-flanking DNA sequence of this gene. In the present study, we have used DNA-protein binding assays to identify trans-acting factors which regulate the temporal expression of the human ε-globin gene during development. Using gel mobility shift assays and DNasel footprinting assays, a nuclear protein factor (termed ε-SSF1) in the nuclear extracts from mouse haematopoietic tissues at d 11 and d 13 of gestation was identified. It could specifically bind to the positive control region (between -535 and -453bp) of the human ε-globin gene. We speculated that the E-SSF1 might be an erythroid- and developmental stage-specific activator. In addition, we found another nuclear protein factor (termed ε-R1) in the nuclear extract from mouse fetal liver at d 18 of gestation, which could strongly bind to the silencer region (between -392 and -177bp) of this gene. Therefore, we speculated that the ε-R1 might be an erythroid- and developmental stagespecific repressor. Our data suggest that both ε-SSF1 and ε-R1 might play important roles in developmental regulation of the human ε-globin gene expression during the early embryonic life. On the other hand, we observed that the binding patterns of nuclear proteins from three cell lines (K562, HEL and Raji) to these regulatory regions were partially different. These results suggest that different trans-acting factors in K562, HEL and Raji cells might be responsible for activating or silencing the human ε-globin gene in three different cell lines.
文摘The DNasel hypersensitive site 2 (HS2) of human β-globin locus control region (LCR) is required fOr the high level expression of human d-globin genes. In the present study, a stage-specific protein factor (LPF-β) was identified in the nuclear extract prepared from mouse fetal liver at d 18 of gestation, which could bind to the HS2 region of humanβ-globin LCRt We also found that the shift band of LPF-βfactor could be competed by humanβ-globin promoter. However, it couldn’t be competed by human E-globin promoter or by human Aβ-globin promoter. Furthermore, our data demonstrated that the binding-sequence of LPF-d factor is 5’CACACCCTA 3’,which is located at the HS2 region ofβ-LCR (from -10845 to -10853 bp) and humanβ-globin promoter (from -92 to -84 bp). We speculated that these regions containing the CACCC box in both the humallβ-globin promoter and HS2 might function as stage selector elements in the regulation of humanβd-globin switching and the LPF-βfactor might be a stage-specific protein factor involved in the regulation of humanβ-globin gene expression.
文摘In order to elucidate the molecular mechanisms of globin gene expression during embryonic development, the nuclear extracts from mouse hematopoietic tissue at different stages of development have been prepared. By using DNase I footprinting and gel mobility shift assays, the binding of protein factors in these extracts to the human βglobin promoter was analyzed. The differences in the binding patterns of protein factors during development were observed. An erythroid-specific and stage-specific nuclear protein in the nuclear extract from d 18 mouse fetal liver was identified, which can bind to the sequence (from -66bp to -90bp) of human β-globin promoter. We therefore speculate that the function of this cis-acting element may be similar to stage selector element (SSE) in chieken βA- promoter.
基金supported by the National Natural Science Foundation of China(Grant Nos.30300450&30070544).
文摘There was a bi-directional promoter between gene 38 kd phosphorylated protein (pp38) gene; 1.8-kb mRNA transcript gene family in the genome of Marek's disease virus (MDV). In this study, enhanced green fluorescence protein (EGFP) reporter plamids, pP(pp38)-EGFP; pP(1.8-kb)-EGFP, were constructed under this bi-directional promoter in two directions. The two plasmids were transfected into uninfected chicken embryo fibroblast (CEF), MDV clone rMd5 infected CEF (rMd5-CEF); pp38-deleted derivative rMd5Δpp38 infected CEF (rMd5Δpp38-CEF) respectively. Transfection analysis showed that EGFP was only expressed in rMd5-CEF,; no EGFP could be detected in uninfected CEF or rMd5Δpp38-CEF, implying that pp38 was a factor influencing the activity of the promoter. The pp38-expressing recombinant plasmid pcDNA-pp38 was constructed to co-transfect CEF or rMd5Δpp38-CEF with pP(pp38)-EGFP or pP(1.8-kb)-EGFP. In this case, EGFP could be detected only in rMd5Δpp38-CEF but still not in uninfected CEF, implying that pp38 needs other protein(s) to work together for the complete trans-acting activity. Another MDV gene, 24 kd phosphorylated protein pp24 gene was cloned into pcDNA3.1 as a pp24-expressing recombinant plasmid pcDNA-pp24. When uninfected CEF was co-transfected with pcDNA-pp38, pcDNA-pp24; EGFP expressing plasmids pP(pp38)-EGFP or pP(1.8-kb)-EGFP, the EGFP could be detected. These results indicated that pp38; pp24 could enhance the activity of the promoter when they worked together. DNA mobility shift assay showed that pp38 would bind to the bi-directional promoter with the co-existing of pp24, although neither of them alone influenced mobility of the promoter DNA. All the above suggested that MDV pp38 could transactivate the bi-directional promoter when combined with pp24. The results also indicated that the activity of the promoter in the direction of 1.8-kb mRNA was significantly stronger than that of pp38 direction.
文摘The two LIM domain-containing proteins from plants （LIMs） typically exhibit a dual cytoplasmic-nuclear dis-tribution, suggesting that, in addition to their previously described roles in actin cytoskeleton organization, they partici-pate in nuclear processes. Using a south-western blot-based screen aimed at identifying factors that bind to plant histone gene promoters, we isolated a positive clone containing the tobacco LIM protein WLIM2 （NtWLIM2） cDNA. Using both green fluorescent protein （GFP） fusion-and immunology-based strategies, we provide clear evidence that NtWLIM2 local-izes to the actin cytoskeleton, the nucleus, and the nucleolus. Interestingly, the disruption of the actin cytoskeleton by latrunculin B significantly increases NtWLIM2 nuclear fraction, pinpointing a possible novel cytoskeletal-nuclear crosstalk. Biochemical and electron microscopy experiments reveal the ability of NtWLIM2 to directly bind to actin filaments and to crosslink the latter into thick actin bundles. Electrophoretic mobility shift assays show that NtWLIM2 specifically binds to the conserved octameric cis-elements （Oct） of the Arabidopsis histone H4A748 gene promoter and that this binding largely relies on both LIM domains. Importantly, reporter-based experiments conducted in Arabidopsis and tobacco proto-plasts confirm the ability of NtWLIM2 to bind to and activate the H4A748 gene promoter in live cells. Expression studies indicate the constitutive presence of NtWLIM2 mRNA and NtWLIM2 protein during tobacco BY-2 cell proliferation and cell cycle progression, suggesting a role of NtWLIM2 in the activation of basal histone gene expression. Interestingly, both live cell and in vitro data support NtWLIM2 di/oligomerization. We propose that NtWLIM2 functions as an actin-stabilizing protein, which, upon cytoskeleton remodeling, shuttles to the nucleus in order to modify gene expression.
基金Project supported by grants from Shanghai Joint Laboratory of Life Sciences, the Chinese Academy of Sciences, and the National Natural Science Foundation of China.
文摘The human ε-globin gene is expressed in a tissue-specific and developmental stage-specific manner. During the earliest stage of gestation, this gene is expressed in the yolksac, but is silenced completely at the 6th-8th weeks of gestation. Recently, several studieson the transgenic mice have shown that the 5′-flanking DNA sequences of human
基金supported by the National Natural Science Foundation of China(31871269)the Hubei Provincial Natural Science Foundation of China(2019CFA014).
文摘Hybrids are always a focus of botanical research and have a high practical value in agricultural production.To better understand allele regulation and differences in DNA methylation in hybrids,we developed a phasing pipeline for hybrid rice based on two parental genomes(PP2PG),which is applicable for Iso-Seq,RNA-Seq,and Bisulfite sequencing(BS-Seq).Using PP2PG,we analyzed differences in gene transcription,alternative splicing,and DNA methylation in an allele-specific manner between parents and progeny or different progeny alleles.The phasing of Iso-Seq data provided a great advantage in separating the whole gene structure and producing a significantly higher separation ratio than RNA-Seq.The interaction of hybrid alleles was studied by constructing an allele co-expression network that revealed the dominant allele effect in the network.The expression variation between parents and the parental alleles in progeny showed tissue-or environment-specific patterns,which implied a preference for trans-acting regulation under different conditions.In addition,by comparing allele-specific DNA methylation,we found that CG methylation was more likely to be inherited than CHG and CHHmethylation,and its enrichment in genic regions was connected to gene structure.In addition to an effective phasing pipeline,we also identified differentiation in OsWAK38 gene structure that may have led to the expansion of allele functions in hybrids.In summary,we developed a phasing pipeline and provided valuable insights into alternative splicing,interaction networks,trans-acting regulation,and the inheritance of DNA methylation in hybrid rice.
