AIM: To investigate the expression of nucleoporin 88 (Nup88) in hepatitis B virus (HBV) and C virus (HCV)-related liver diseases. METHODS: We generated a new monoclonal Nup88 antibody to investigate the Nup88 protein ...AIM: To investigate the expression of nucleoporin 88 (Nup88) in hepatitis B virus (HBV) and C virus (HCV)-related liver diseases. METHODS: We generated a new monoclonal Nup88 antibody to investigate the Nup88 protein expression by immunohistochemistry (IHC) in 294 paraffin-embedded liver specimens comprising all stages of hepatocellular carcinogenesis. In addition, in cell culture experiments HBV-positive (HepG2.2.15 and HB611) and HBV-negative (HepG2) hepatoma cell lines were tested for the Nup88 expression by Western-immunoblotting to test data obtained by IHC.RESULTS: Specific Nup88 expression was found in chronic HCV hepatitis and unspecific chronic hepatitis, whereas no or very weak Nup88 expression was detected in normal liver. The Nup88 expression was markedly reduced or missing in mild chronic HBV infection and inversely correlated with HBcAg expression. Irrespective of the HBV- or HCV-status, increasing Nup88 expression was observed in cirrhosis and dysplastic nodules, and Nup88 was highly expressed in hepatocellular carcinomas. The intensity of Nup88 expression significantly increased during carcinogenesis (P < 0.0001) and correlated with dedifferentiation (P < 0.0001). Interestingly, Nup88 protein expression was significantly downregulated in HBV-positive HepG2.2.15 (P < 0.002) and HB611 (P < 0.001) cell lines as compared to HBV-negative HepG2 cells. CONCLUSION: Based on our immunohistochemical data, HBV and HCV are unlikely to influence the expression of Nup88 in cirrhotic and neoplastic liver tissue, but point to an interaction of HBV with the nuclear pore in chronic hepatitis. The expression of Nup88 in nonneoplastic liver tissue might reflect enhanced metabolic activity of the liver tissue. Our data strongly indicate a dichotomous role for Nup88 in non-neoplastic and neoplastic conditions of the liver.展开更多
The human myxovirus resistance 2(Mx2/Mx B)protein,a member of interferon(IFN)-inducible dynamin-like large GTPases,restricts a number of virus infections.Inhibition of these viruses occurs at poorly-defined steps afte...The human myxovirus resistance 2(Mx2/Mx B)protein,a member of interferon(IFN)-inducible dynamin-like large GTPases,restricts a number of virus infections.Inhibition of these viruses occurs at poorly-defined steps after viral entry and has a common requirement for Mx B oligomerization.However,the GTPase activity is essential for the anti-viral effects of Mx B against herpesviruses and HBV but not HIV-1.To understand the role of Mx B GTPase activity,including GTP binding and GTP hydrolysis,in restriction of HIV-1 infection,we genetically separated these two functions and evaluated their contributions to restriction.We found that both the GTP binding and hydrolysis function of Mx B involved in the restriction of HIV-1 replication.The GTPase activity of Mx B contributed to its nuclear location,interaction with nucleoporins(NUPs)and HIV-1 capsids.Furthermore,Mx B disrupted the association between NUPs and HIV-1 cores dependently upon its GTPase activity.The function of GTPase activity was therefore multi-faceted,led to fundamentally distinct mechanisms employed by wild-type Mx B and GTPase activity defective Mx B mutations to restrict HIV-1 replication.展开更多
Flowering locus C(FLC)is a central transcriptional repressor that controls flowering time.However,how FLC is imported into the nucleus is unknown.Here,we report that Arabidopsis nucleoporins 62(NUP62),NUP58,and NUP54 ...Flowering locus C(FLC)is a central transcriptional repressor that controls flowering time.However,how FLC is imported into the nucleus is unknown.Here,we report that Arabidopsis nucleoporins 62(NUP62),NUP58,and NUP54 composed NUP62-subcomplex modulates FLC nuclear import during floral transition in an importinα-independent manner,via direct interaction.NUP62 recruits FLC to the cytoplasmic filaments and imports it into the nucleus through the NUP62-subcomplex composed central channel.Importinβsupersensitive to ABA and drought 2(SAD2),a carrier protein,is critical for FLC nuclear import and flower transition,which facilitates FLC import into the nucleus mainly through the NUP62-subcomplex.Proteomics,RNAseq,and cell biological analyses indicate that the NUP62-subcomplex mainly mediates the nuclear import of cargos with unconventional nuclear localization sequences(NLSs),such as FLC.Our findings illustrate the mechanisms of the NUP62-subcomplex and SAD2 on FLC nuclear import process and floral transition,and provide insights into the role of NUP62-subcomplex and SAD2 in protein nucleocytoplasmic transport in plants.展开更多
文摘AIM: To investigate the expression of nucleoporin 88 (Nup88) in hepatitis B virus (HBV) and C virus (HCV)-related liver diseases. METHODS: We generated a new monoclonal Nup88 antibody to investigate the Nup88 protein expression by immunohistochemistry (IHC) in 294 paraffin-embedded liver specimens comprising all stages of hepatocellular carcinogenesis. In addition, in cell culture experiments HBV-positive (HepG2.2.15 and HB611) and HBV-negative (HepG2) hepatoma cell lines were tested for the Nup88 expression by Western-immunoblotting to test data obtained by IHC.RESULTS: Specific Nup88 expression was found in chronic HCV hepatitis and unspecific chronic hepatitis, whereas no or very weak Nup88 expression was detected in normal liver. The Nup88 expression was markedly reduced or missing in mild chronic HBV infection and inversely correlated with HBcAg expression. Irrespective of the HBV- or HCV-status, increasing Nup88 expression was observed in cirrhosis and dysplastic nodules, and Nup88 was highly expressed in hepatocellular carcinomas. The intensity of Nup88 expression significantly increased during carcinogenesis (P < 0.0001) and correlated with dedifferentiation (P < 0.0001). Interestingly, Nup88 protein expression was significantly downregulated in HBV-positive HepG2.2.15 (P < 0.002) and HB611 (P < 0.001) cell lines as compared to HBV-negative HepG2 cells. CONCLUSION: Based on our immunohistochemical data, HBV and HCV are unlikely to influence the expression of Nup88 in cirrhotic and neoplastic liver tissue, but point to an interaction of HBV with the nuclear pore in chronic hepatitis. The expression of Nup88 in nonneoplastic liver tissue might reflect enhanced metabolic activity of the liver tissue. Our data strongly indicate a dichotomous role for Nup88 in non-neoplastic and neoplastic conditions of the liver.
基金supported by the National Science Foundation of China(81271818 and 81471940 to YF,and 81471941,81871659 and 81828005 to WH)
文摘The human myxovirus resistance 2(Mx2/Mx B)protein,a member of interferon(IFN)-inducible dynamin-like large GTPases,restricts a number of virus infections.Inhibition of these viruses occurs at poorly-defined steps after viral entry and has a common requirement for Mx B oligomerization.However,the GTPase activity is essential for the anti-viral effects of Mx B against herpesviruses and HBV but not HIV-1.To understand the role of Mx B GTPase activity,including GTP binding and GTP hydrolysis,in restriction of HIV-1 infection,we genetically separated these two functions and evaluated their contributions to restriction.We found that both the GTP binding and hydrolysis function of Mx B involved in the restriction of HIV-1 replication.The GTPase activity of Mx B contributed to its nuclear location,interaction with nucleoporins(NUPs)and HIV-1 capsids.Furthermore,Mx B disrupted the association between NUPs and HIV-1 cores dependently upon its GTPase activity.The function of GTPase activity was therefore multi-faceted,led to fundamentally distinct mechanisms employed by wild-type Mx B and GTPase activity defective Mx B mutations to restrict HIV-1 replication.
基金The Work Was Supported by the National Natural Science Foundation of China, the National Key Basic Research Project (No.2004CB117400),the Program for New Century Excellent Talents in University and the Key Project of Chinese Ministry of Education.
基金supported by grants from the National Natural Science Foundation(31970730 and 32170721)to H.Hthe Baichuan felowship from College of Life Science and Technology,Huazhong Agricultural University to D.X。
文摘Flowering locus C(FLC)is a central transcriptional repressor that controls flowering time.However,how FLC is imported into the nucleus is unknown.Here,we report that Arabidopsis nucleoporins 62(NUP62),NUP58,and NUP54 composed NUP62-subcomplex modulates FLC nuclear import during floral transition in an importinα-independent manner,via direct interaction.NUP62 recruits FLC to the cytoplasmic filaments and imports it into the nucleus through the NUP62-subcomplex composed central channel.Importinβsupersensitive to ABA and drought 2(SAD2),a carrier protein,is critical for FLC nuclear import and flower transition,which facilitates FLC import into the nucleus mainly through the NUP62-subcomplex.Proteomics,RNAseq,and cell biological analyses indicate that the NUP62-subcomplex mainly mediates the nuclear import of cargos with unconventional nuclear localization sequences(NLSs),such as FLC.Our findings illustrate the mechanisms of the NUP62-subcomplex and SAD2 on FLC nuclear import process and floral transition,and provide insights into the role of NUP62-subcomplex and SAD2 in protein nucleocytoplasmic transport in plants.
