AIM: To search for the presence of cis elements in hepatitis D virus(HDV) genomic and antigenomic RNA capable of promoting nuclear export. METHODS: We made use of a well characterized chloramphenicol acetyl-transferas...AIM: To search for the presence of cis elements in hepatitis D virus(HDV) genomic and antigenomic RNA capable of promoting nuclear export. METHODS: We made use of a well characterized chloramphenicol acetyl-transferase reporter system based on plasmid p DM138. Twenty c DNA fragments corresponding to different HDV genomic and antigenomic RNA sequences were inserted in plasmid pD M138, and used in transfection experiments in Huh7 cells. The relative amounts of HDV RNA in nuclear and cytoplasmic fractions were then determined by realtime polymerase chain reaction and Northern blotting. The secondary structure of the RNA sequences that displayed nuclear export ability was further predicted using a web interface. Finally, the sensitivity to leptomycin B was assessed in order to investigate possible cellular pathways involved in HDV RNA nuclear export.RESULTS: Analysis of genomic RNA sequences did not allow identifying an unequivocal nuclear export element. However, two regions were found to promote the export of reporter m RNAs with efficiency higher than the negative controls albeit lower than the positive control. These regions correspond to nucleotides 266-489 and 584-920, respectively. In addition, when analyzing antigenomic RNA sequences a nuclear export element was found in positions 214-417. Export mediated by the nuclear export element of HDV antigenomic RNA is sensitive to leptomycin B suggesting a possible role of CRM1 in this transport pathway. CONCLUSION: A cis-acting nuclear export element is present in nucleotides 214-417 of HDV antigenomic RNA.展开更多
UPR is a conserved response in eukaryotes and can alleviate endoplasmic reticulum(ER)stresses induced by abiotic and biotic stresses.The interactions between UPR and plant RNA viruses have been documented,while the in...UPR is a conserved response in eukaryotes and can alleviate endoplasmic reticulum(ER)stresses induced by abiotic and biotic stresses.The interactions between UPR and plant RNA viruses have been documented,while the interplays between UPR and plant DNA viruses remain unknown.Using tomato yellow leaf curl China virus(TYLCCNV)and its associated betasatellite(TYLCCNB)as a model,we indicate that TYLCCNBβC1 is a major inducer of UPR and can upregulate the expression of b ZIP60,a transcription factor in Nicotiana benthamiana plants.Treatment using ER stress inducers or overexpression of Nbb ZIP60 increasesβC1 accumulation and benefits TYLCCNV/TYLCCNB infection in N.benthamiana plants,and vice versa.In the TYLCCNV/TYLCCNB-infected or theβC1-expressing cells,Nbb ZIP60 is exported from the nucleus to the nuclear periphery via the XPO1 pathway,and blocking the XPO1 pathway inhibited TYLCCNV/TYLCCNB infection.We have found that the Nbb ZIP60-regulated pro-survival genes could promote virus infection,and the pro-death gene plays a contrasting role in virus infection.This study reveals that geminivirus infection activates UPR and utilizes the up-regulated molecular chaperons to promote viral infection,and then induces the nuclear export of Nbb ZIP60 to evade plant defense response,which is a distinct virulence strategy exploited by plant pathogens.展开更多
NUP98 fuses with approximately 34 different partner genes via translocation in hematological malignancies. Transgenic or retrovirus-mediated bone marrow transplanted mouse models reveal the leukemogenesis of some NUP9...NUP98 fuses with approximately 34 different partner genes via translocation in hematological malignancies. Transgenic or retrovirus-mediated bone marrow transplanted mouse models reveal the leukemogenesis of some NUP98-related fusion genes. We previously reported the fusion protein NUP98-IQ motif containing G （IQCG） in a myeloid/T lymphoid bi-phenoleukemia patient with t（3;11） and confirmed its leukemogenic ability. Herein, we demonstrated the association of NUP98-IQCG with CRM1, and found that NUP98-IQCG expression inhibits the CRMl-mediated nuclear export of p65 and enhances the transcriptional activity of nuclear factor-κB. Moreover, IQCG could be entrapped in the nucleus by NUP98-IQCG, and the fusion protein interacts with calmodulin via the IQ motif in a calcium-independent manner. Therefore, the inhibition of nuclear exports of p65 and IQCG might contribute to the leukemogenesis of NUP98-IQCG.展开更多
To the Editor:Multiple myeloma(MM)is a plasma cell disease that remains incurable.Novel anti-MMtherapies are currently in clinical research,including CAR-T therapy,bispecific antibodies,and XPO1 inhibitors1.XPO1 is a ...To the Editor:Multiple myeloma(MM)is a plasma cell disease that remains incurable.Novel anti-MMtherapies are currently in clinical research,including CAR-T therapy,bispecific antibodies,and XPO1 inhibitors1.XPO1 is a nuclear export protein that helps leucine-rich proteins transport from the nucleus to the cytoplasm.XPO1 is highly expressed in patients with MM and XPO1 overexpression is associated with short PFS and OS^(2).These observations suggest that XPO1 has considerable value as a therapeutic target for patients with MM.展开更多
As a critical apoptosis executioner, caspase-3 becomes activated and then enters into the nucleus to exert its function. However, the molecular mechanism of this nuclear entry of active caspase-3 is still unknown. In ...As a critical apoptosis executioner, caspase-3 becomes activated and then enters into the nucleus to exert its function. However, the molecular mechanism of this nuclear entry of active caspase-3 is still unknown. In this study, we revealed that easpase-3 harbors a crm-l-independent nuclear export signal （NES） in its small subunit. Using reversecaspase-3 as the study model, we found that the function of the NES in caspase-3 was not disturbed by the conformational changes during induced caspase-3 activation. Mutations disrupting the cleavage activity or p3-recognition site resulted in a defect in the nuclear entry of active caspase-3. We provide evidence that the p3-mediated specific cleavage activity of active caspase-3 abrogated the function of the NES. In conclusion, our results demonstrate that during caspase-3 activation, NES is constitutively present, p3-mediated specific cleavage activity abrogates the NES function in caspase-3, thus facilitating the nuclear entry of active caspase-3.展开更多
旨在探讨热应激对H9c2心肌细胞构成型HSP70(constitutive or cognate HSPs,Hsc70)出入核及细胞凋亡的影响。以42℃作为热应激模型温度,通过转染Hsc70siRNA抑制Hsc70表达,Western blot检测细胞质和细胞核内Hsc70表达,ELISA检测细胞培养液...旨在探讨热应激对H9c2心肌细胞构成型HSP70(constitutive or cognate HSPs,Hsc70)出入核及细胞凋亡的影响。以42℃作为热应激模型温度,通过转染Hsc70siRNA抑制Hsc70表达,Western blot检测细胞质和细胞核内Hsc70表达,ELISA检测细胞培养液LDH浓度,Annexin V-FITC/PI双染法检测细胞凋亡。结果表明,正常H9c2心肌细胞质Hsc70表达量较高,细胞核中表达量很低,细胞质和细胞核Hsp72表达量非常低。热应激后细胞质Hsc70表达量无显著差异,而细胞核Hsc70热应激30和100min后极显著升高(P<0.01),热应激240min后开始降低;细胞质和细胞核Hsp72热应激后显著升高(P<0.05或P<0.01)。Hsc70抑制表达后,细胞质Hsc70水平显著降低,热应激后Hsc70入核明显减少,但仍然有入核现象;Hsc70抑制表达对细胞质和细胞核Hsp72表达无显著影响。与热应激组相比,热应激+Hsc70siRNA组LDH表达量呈升高趋势,热应激100min两组出现显著差异(P<0.05);Hsc70抑制表达后H9c2细胞在热应激后更容易发生凋亡,而且在热应激30和100min内,两组之间存在显著差异(P<0.05)。结果提示,热应激可诱使Hsc70出入细胞核,Hsc70抑制表达后热应激诱导Hsc70入核显著降低,细胞损伤加重,细胞凋亡升高。展开更多
The herpes simplex virus type 1 （HSV-1） infected-cell protein 27 （ICP27） is an essential, highly conserved protein involved in various steps of HSV-1 gene regulation as well as in the shut-off of host gene express...The herpes simplex virus type 1 （HSV-1） infected-cell protein 27 （ICP27） is an essential, highly conserved protein involved in various steps of HSV-1 gene regulation as well as in the shut-off of host gene expression during infection. It functions primarily at the post-transcriptional level in inhibiting precursor mRNA splicing and in promoting nuclear export of viral transcripts. Recently, many novel functions performed by the HSV- 1 ICP27 protein were shown, including leptomycin B resistance, inhibition of the type I interferon signaling, regulation of the viral mRNA translation and determining the composition of HSV-1 virions展开更多
基金Supported by A grant from Fundao para a Ciência e Tecnologia,Portugal to Freitas N
文摘AIM: To search for the presence of cis elements in hepatitis D virus(HDV) genomic and antigenomic RNA capable of promoting nuclear export. METHODS: We made use of a well characterized chloramphenicol acetyl-transferase reporter system based on plasmid p DM138. Twenty c DNA fragments corresponding to different HDV genomic and antigenomic RNA sequences were inserted in plasmid pD M138, and used in transfection experiments in Huh7 cells. The relative amounts of HDV RNA in nuclear and cytoplasmic fractions were then determined by realtime polymerase chain reaction and Northern blotting. The secondary structure of the RNA sequences that displayed nuclear export ability was further predicted using a web interface. Finally, the sensitivity to leptomycin B was assessed in order to investigate possible cellular pathways involved in HDV RNA nuclear export.RESULTS: Analysis of genomic RNA sequences did not allow identifying an unequivocal nuclear export element. However, two regions were found to promote the export of reporter m RNAs with efficiency higher than the negative controls albeit lower than the positive control. These regions correspond to nucleotides 266-489 and 584-920, respectively. In addition, when analyzing antigenomic RNA sequences a nuclear export element was found in positions 214-417. Export mediated by the nuclear export element of HDV antigenomic RNA is sensitive to leptomycin B suggesting a possible role of CRM1 in this transport pathway. CONCLUSION: A cis-acting nuclear export element is present in nucleotides 214-417 of HDV antigenomic RNA.
基金supported by the National Key Research and Development Program of China (2021YFD1400400)the National Natural Science Foundation of China (32172385,31930089)。
文摘UPR is a conserved response in eukaryotes and can alleviate endoplasmic reticulum(ER)stresses induced by abiotic and biotic stresses.The interactions between UPR and plant RNA viruses have been documented,while the interplays between UPR and plant DNA viruses remain unknown.Using tomato yellow leaf curl China virus(TYLCCNV)and its associated betasatellite(TYLCCNB)as a model,we indicate that TYLCCNBβC1 is a major inducer of UPR and can upregulate the expression of b ZIP60,a transcription factor in Nicotiana benthamiana plants.Treatment using ER stress inducers or overexpression of Nbb ZIP60 increasesβC1 accumulation and benefits TYLCCNV/TYLCCNB infection in N.benthamiana plants,and vice versa.In the TYLCCNV/TYLCCNB-infected or theβC1-expressing cells,Nbb ZIP60 is exported from the nucleus to the nuclear periphery via the XPO1 pathway,and blocking the XPO1 pathway inhibited TYLCCNV/TYLCCNB infection.We have found that the Nbb ZIP60-regulated pro-survival genes could promote virus infection,and the pro-death gene plays a contrasting role in virus infection.This study reveals that geminivirus infection activates UPR and utilizes the up-regulated molecular chaperons to promote viral infection,and then induces the nuclear export of Nbb ZIP60 to evade plant defense response,which is a distinct virulence strategy exploited by plant pathogens.
基金This work was supported by the National Basic Research Program of China （No. 2013CB966800）, Ministry of Health （No.201202003）, the Mega-projects of Scientific Research for the 12th Five-Year Plan （No. 2013ZX09303302）, the State Key Laboratories Project ofExcellence （No. 81123005）, the National Natural Science Foundation of China （Nos. 81222004 and 81170506）, and the Samuel Waxman Cancer Research Foundation Co-PI Program.
文摘NUP98 fuses with approximately 34 different partner genes via translocation in hematological malignancies. Transgenic or retrovirus-mediated bone marrow transplanted mouse models reveal the leukemogenesis of some NUP98-related fusion genes. We previously reported the fusion protein NUP98-IQ motif containing G （IQCG） in a myeloid/T lymphoid bi-phenoleukemia patient with t（3;11） and confirmed its leukemogenic ability. Herein, we demonstrated the association of NUP98-IQCG with CRM1, and found that NUP98-IQCG expression inhibits the CRMl-mediated nuclear export of p65 and enhances the transcriptional activity of nuclear factor-κB. Moreover, IQCG could be entrapped in the nucleus by NUP98-IQCG, and the fusion protein interacts with calmodulin via the IQ motif in a calcium-independent manner. Therefore, the inhibition of nuclear exports of p65 and IQCG might contribute to the leukemogenesis of NUP98-IQCG.
基金supported by grants from the National Natural Science Foundation of China(Nos.82070223 and 82370205)the Social Development Project of Jiangsu Science and Technology Plan(No.BE2022810,China).
文摘To the Editor:Multiple myeloma(MM)is a plasma cell disease that remains incurable.Novel anti-MMtherapies are currently in clinical research,including CAR-T therapy,bispecific antibodies,and XPO1 inhibitors1.XPO1 is a nuclear export protein that helps leucine-rich proteins transport from the nucleus to the cytoplasm.XPO1 is highly expressed in patients with MM and XPO1 overexpression is associated with short PFS and OS^(2).These observations suggest that XPO1 has considerable value as a therapeutic target for patients with MM.
基金Supplementary information is linked to the online version of the paper on the Cell Research website.Acknowledgments We thank Prof Jian Wang （Shanghai University, Shanghai） for his valuable revision and discussion. This work was supported by grants from the National Natural Science Foundation of China （30700411）, Shenzhen Bureau of Science Technology and Information （SZKJ-2006018, SZKJ-2007012）, Shenzhen Nanshan Bureau of Science Technology and Information （2008036） and Shenzhen Key Laboratory Advancement Scheme.
文摘As a critical apoptosis executioner, caspase-3 becomes activated and then enters into the nucleus to exert its function. However, the molecular mechanism of this nuclear entry of active caspase-3 is still unknown. In this study, we revealed that easpase-3 harbors a crm-l-independent nuclear export signal （NES） in its small subunit. Using reversecaspase-3 as the study model, we found that the function of the NES in caspase-3 was not disturbed by the conformational changes during induced caspase-3 activation. Mutations disrupting the cleavage activity or p3-recognition site resulted in a defect in the nuclear entry of active caspase-3. We provide evidence that the p3-mediated specific cleavage activity of active caspase-3 abrogated the function of the NES. In conclusion, our results demonstrate that during caspase-3 activation, NES is constitutively present, p3-mediated specific cleavage activity abrogates the NES function in caspase-3, thus facilitating the nuclear entry of active caspase-3.
基金Start Fund of the Hundred Talents Program of the Chinese Academy of Science (20071010-141)National Natural Science Foundation of China(30870120)Open Research Fund Program of the State Key Laboratory of Virology of China (2007003)
文摘The herpes simplex virus type 1 （HSV-1） infected-cell protein 27 （ICP27） is an essential, highly conserved protein involved in various steps of HSV-1 gene regulation as well as in the shut-off of host gene expression during infection. It functions primarily at the post-transcriptional level in inhibiting precursor mRNA splicing and in promoting nuclear export of viral transcripts. Recently, many novel functions performed by the HSV- 1 ICP27 protein were shown, including leptomycin B resistance, inhibition of the type I interferon signaling, regulation of the viral mRNA translation and determining the composition of HSV-1 virions
