Plant viruses pose significant threats to agriculture,with many vectored by insect pests.The entry of viruses and their encoded proteins into the host nucleus is a critical step for promoting some viral replication an...Plant viruses pose significant threats to agriculture,with many vectored by insect pests.The entry of viruses and their encoded proteins into the host nucleus is a critical step for promoting some viral replication and enabling systemic infection.Laodelphax striatellus,also known as the small brown planthopper(SBPH),is an efficient vector for rice stripe virus(RSV),one of the most damaging viruses of rice.In this study,we demonstrate that RSV infection induces the expression of genes in both the classical and non-classical nuclear import pathways of SBPH.A gene belonging to the importinβfamily,importin 5(LsIPO5),was upregulated by 84%in SBPH midguts infected with RSV.The nuclear localization signal(NLS,^(168)YRSPSKKRHKYV^(179))is located within the nonstructural protein NS3 directly bound to LsIPO5,thereby facilitating NS3nuclear entry.Moreover,a RING-type E3 ligase(LsRING)in SBPH,which mediated the ubiquitination of NS3 in the insect vector,enhanced NS3 binding to LsIPO5 and facilitated NS3 perinuclear localization.Combined treatment of SBPH with both ds IPO5 and ds RING significantly reduced RSV loads,highlighting the importance of LsIPO5 and NS3 ubiquitination cooperation in facilitating viral replication.Our findings provide new insights into synergistic molecular mechanisms that govern RSV infection and suggest potential therapeutic targets to control viral transmission through their insect vectors.展开更多
家蚕核型多角体病毒(Bombyx mori nucleopolyhedrovirus, BmNPV)对蚕丝业的危害极大。该病毒的多角体蛋白编码基因polyhedrin(polh)能够在病毒感染极晚期超高水平表达,并在细胞核内形成包涵体,多角体蛋白转运到宿主细胞核中的详细机制...家蚕核型多角体病毒(Bombyx mori nucleopolyhedrovirus, BmNPV)对蚕丝业的危害极大。该病毒的多角体蛋白编码基因polyhedrin(polh)能够在病毒感染极晚期超高水平表达,并在细胞核内形成包涵体,多角体蛋白转运到宿主细胞核中的详细机制目前未知。为阐明病毒蛋白的入核机制,本研究通过分子克隆、免疫共沉淀(co-immunoprecipitation, CO-IP)、免疫荧光等方法,详细分析了多角体蛋白(polyhedrin, Polh)的表达规律,并进一步揭示了宿主蛋白importin α通过蛋白互作的方式参与多角体蛋白的入核转运,为进一步深入阐明包括Polh在内的诸多杆状病毒入核蛋白的入核机制提供了参考。展开更多
Importin proteins were originally characterized for their central role in protein transport through the nuclear pores, the only intracellular entry to the nucleus. This vital function must be tightly regulated to cont...Importin proteins were originally characterized for their central role in protein transport through the nuclear pores, the only intracellular entry to the nucleus. This vital function must be tightly regulated to control access by transcription factors and other nuclear proteins to genomic DNA, to achieve appropriate modulation of cellular behaviors affecting cell fate. Importin-mediated nucleocytoplasmic transport relies on their specific recognition of cargoes, with each importin binding to distinct and overlapping protein subsets. Knowledge of importin function has expanded substantially in regard to three key developmental systems： embryonic stem cells, muscle cells and the germ line. In the decade since the potential for regulated nucleocytoplasmic transport to contribute to spermatogenesis was proposed, we and others have shown that the importins that ferry transcription factors into the nucleus perform additional roles, which control cell fate. This review presents key findings from studies of mammalian spermatogenesis that reveal potential new pathways by which male fertility and infertility arise. These studies of germline genesis illuminate new ways in which importin proteins govern cellular differentiation, includ ng v a d rect ng proteins to d st nct ntrace ular compartments and by determining cellular stress responses.展开更多
Tip60 is a specific member of MYST (Moz-Ybf2/Sas3-Sas2-Tip60) family of nuclear histone acetyltransferases (HAT). It is essential for cellular survival, differentiation, and metabolism. A putative canonical NLS motif ...Tip60 is a specific member of MYST (Moz-Ybf2/Sas3-Sas2-Tip60) family of nuclear histone acetyltransferases (HAT). It is essential for cellular survival, differentiation, and metabolism. A putative canonical NLS motif between the chromo domain and the zinc finger of Tip60 was identified. Here we show evidence that Tip60 is associated with importin α as its substrate and transported from cytoplasm to the nucleus. Pull down assay revealed that Tip60 was physically associated with importin α both in vivo and in vitro. Confocal microscopic observation showed that Tip60 and importin α were co-localized with each other. The localization of Tip60 to the nuclear and its interaction with importin α was disrupted when its putative NLS motif for binding to importin α was mutated (219RKRK222 → 219AAAA222). However, attachment of this putative NLS motif to a cytoplasmic protein (YAP 1-210 fragment) promoted its nuclear localization. Based on transient transfection, Tip60 NLS motif mutant showed a substantial reduction in self-acetylation, HAT activity, and apoptotic ability whereas wild type Tip60 did not show such reduction. Taken together, our results demonstrate that importin α transports Tip60 from the cytoplasm to the nucleus through binding to the putative NLS motif of Tip60 for its tumor suppressing function.展开更多
基金supported by the Natural Science Foundation of Jiangsu Province,China(BK20240902 and BK20240904)the National Natural Science Foundation of China(32272533)。
文摘Plant viruses pose significant threats to agriculture,with many vectored by insect pests.The entry of viruses and their encoded proteins into the host nucleus is a critical step for promoting some viral replication and enabling systemic infection.Laodelphax striatellus,also known as the small brown planthopper(SBPH),is an efficient vector for rice stripe virus(RSV),one of the most damaging viruses of rice.In this study,we demonstrate that RSV infection induces the expression of genes in both the classical and non-classical nuclear import pathways of SBPH.A gene belonging to the importinβfamily,importin 5(LsIPO5),was upregulated by 84%in SBPH midguts infected with RSV.The nuclear localization signal(NLS,^(168)YRSPSKKRHKYV^(179))is located within the nonstructural protein NS3 directly bound to LsIPO5,thereby facilitating NS3nuclear entry.Moreover,a RING-type E3 ligase(LsRING)in SBPH,which mediated the ubiquitination of NS3 in the insect vector,enhanced NS3 binding to LsIPO5 and facilitated NS3 perinuclear localization.Combined treatment of SBPH with both ds IPO5 and ds RING significantly reduced RSV loads,highlighting the importance of LsIPO5 and NS3 ubiquitination cooperation in facilitating viral replication.Our findings provide new insights into synergistic molecular mechanisms that govern RSV infection and suggest potential therapeutic targets to control viral transmission through their insect vectors.
文摘Importin proteins were originally characterized for their central role in protein transport through the nuclear pores, the only intracellular entry to the nucleus. This vital function must be tightly regulated to control access by transcription factors and other nuclear proteins to genomic DNA, to achieve appropriate modulation of cellular behaviors affecting cell fate. Importin-mediated nucleocytoplasmic transport relies on their specific recognition of cargoes, with each importin binding to distinct and overlapping protein subsets. Knowledge of importin function has expanded substantially in regard to three key developmental systems： embryonic stem cells, muscle cells and the germ line. In the decade since the potential for regulated nucleocytoplasmic transport to contribute to spermatogenesis was proposed, we and others have shown that the importins that ferry transcription factors into the nucleus perform additional roles, which control cell fate. This review presents key findings from studies of mammalian spermatogenesis that reveal potential new pathways by which male fertility and infertility arise. These studies of germline genesis illuminate new ways in which importin proteins govern cellular differentiation, includ ng v a d rect ng proteins to d st nct ntrace ular compartments and by determining cellular stress responses.
文摘Tip60 is a specific member of MYST (Moz-Ybf2/Sas3-Sas2-Tip60) family of nuclear histone acetyltransferases (HAT). It is essential for cellular survival, differentiation, and metabolism. A putative canonical NLS motif between the chromo domain and the zinc finger of Tip60 was identified. Here we show evidence that Tip60 is associated with importin α as its substrate and transported from cytoplasm to the nucleus. Pull down assay revealed that Tip60 was physically associated with importin α both in vivo and in vitro. Confocal microscopic observation showed that Tip60 and importin α were co-localized with each other. The localization of Tip60 to the nuclear and its interaction with importin α was disrupted when its putative NLS motif for binding to importin α was mutated (219RKRK222 → 219AAAA222). However, attachment of this putative NLS motif to a cytoplasmic protein (YAP 1-210 fragment) promoted its nuclear localization. Based on transient transfection, Tip60 NLS motif mutant showed a substantial reduction in self-acetylation, HAT activity, and apoptotic ability whereas wild type Tip60 did not show such reduction. Taken together, our results demonstrate that importin α transports Tip60 from the cytoplasm to the nucleus through binding to the putative NLS motif of Tip60 for its tumor suppressing function.
