The La (SS-B) autoimmune antigen is an RNA-binding protein that is present in both nucleus and cytoplasm of eukaryotic cells.The spectrum of RNAs that interact with the antigen includes species which also bind to the ...The La (SS-B) autoimmune antigen is an RNA-binding protein that is present in both nucleus and cytoplasm of eukaryotic cells.The spectrum of RNAs that interact with the antigen includes species which also bind to the interferon-inducible protein kinase PKR.We have investigated whether the La antigen can regulate the activity of PKR and have observed that both the autophosphorylation of the protein kinase that accompanies its activation by dsRNA and the dsRNA-dependent phosphorylation of the subunit of polypeptide chain initiation factor eIF-2 by PKR are inhibited in the presence of recombinant La antigen. This inhibition is partially relieved at higher concentrations of dsRNA.Once activated by dsRNA the protein kinase activity of PKR is insensitive to the La antigen. We have demonstrated by a filter binding assay that La is a dsRNA binding protein.Furthermore, when recombinant La is incubated with a 900bp synthetic dsRNA or with naturally occurring reovirus dsRNA it converts these substrates to single-stranded forms.We conclude that the La antigen inhibits the dsRNA-dependent activation of PKR by binding and unwinding dsRNA and that it may therefore play a role in the regulation of this protein kinase in interferon-treated or virus-infected cells.展开更多
新近研究发现 ,人类 L a蛋白 (hum an L a protein,h L a)是一种与 HBV RNA转录调节相关的因子。L a蛋白可能结合在 HBV RNAs的茎环结构上 ,具有保护乙肝病毒 (hepatitis B virus,HBV) RNA,促进其翻译启动的作用 ,可能是 HBV RNA的稳定...新近研究发现 ,人类 L a蛋白 (hum an L a protein,h L a)是一种与 HBV RNA转录调节相关的因子。L a蛋白可能结合在 HBV RNAs的茎环结构上 ,具有保护乙肝病毒 (hepatitis B virus,HBV) RNA,促进其翻译启动的作用 ,可能是 HBV RNA的稳定因子。当 L a蛋白发生突变后将无法与 HBV RNA结合 ,丧失保护 HBV RNA的功能 ,使其受到酶的降解 ,无法转录翻译 ,病毒的复制受阻 ,从而抑制 HBV感染。本文综述了 L a蛋白、HBV RNA及核酶 (nuclear RNases)三者间相互作用关系的最新研究成果 ,从分子水平上探讨了导致 HBV RNA降解的可能机制 ,推测了野生型和突变型 L a蛋白对乙型肝炎病毒展开更多
以新城疫病毒(Newcastlediseace virus,NDV)La sota F蛋白的氨基酸序列为基础,采用Chou-Fasman法、Garnier-Robson法、Karplus-Schulz法与Kyte-Doolittle法、Emini法和Jameson-Wolf法分别预测蛋白质的二级结构和B细胞抗原表位。预测结...以新城疫病毒(Newcastlediseace virus,NDV)La sota F蛋白的氨基酸序列为基础,采用Chou-Fasman法、Garnier-Robson法、Karplus-Schulz法与Kyte-Doolittle法、Emini法和Jameson-Wolf法分别预测蛋白质的二级结构和B细胞抗原表位。预测结果表明,NDV La Sota F蛋白结构较为复杂,含有较多的α-螺旋、β-折叠区,转角和无规则卷曲等有柔韧性区域。此外,应用Tmap法预测了NDV La sota F蛋白的跨膜区域,通过同源建模的方法预测了该蛋白的三维空间结构,并比较了强弱毒株裂解位点处空间结构的不同。为进一步通过试验方法确定其蛋白的B细胞表位和从结构出发了解其生物学功能,提供了理论依据。展开更多
目的:分析微小核糖核酸-211(micro ribonucleic acid-211,miR-211)、La相关蛋白1(La-associated protein 1,LARP1)、转录辅助因子退变样蛋白4(transcription-assisted factor deformable protein 4,VGLL4)在胃癌组织中的表达及意义。方...目的:分析微小核糖核酸-211(micro ribonucleic acid-211,miR-211)、La相关蛋白1(La-associated protein 1,LARP1)、转录辅助因子退变样蛋白4(transcription-assisted factor deformable protein 4,VGLL4)在胃癌组织中的表达及意义。方法:收集98例胃癌患者,并取胃癌组织距离肿瘤边缘5 cm的癌旁组织43例。比较胃癌组织和癌旁组织miR-211,LARP1,VGLL4表达情况和以上指标与胃癌患者临床病理特征及生存情况的关系。结果:胃癌患者miR-211及LARP1高表达率高于癌旁组织,VGLL4高表达率低于癌旁组织(均P<0.05)。MiR-211,LARP1,VGLL4表达在TNM分期、淋巴结转移、浸润深度中差异有统计学意义(P<0.05)。MiR-211及LARP1高表达者3年生存率分别低于miR-211及LARP1低表达者,VGLL4高表达者3年生存率高于低表达者(P<0.05)。Cox比例风险模型分析显示TNM分期、淋巴结转移、浸润深度、miR-211、LARP1为胃癌预后的危险因素,VGLL4为保护因素。miR-211与LARP1呈正相关,miR-211与VGLL4,LARP1与VEGLL4呈负相关。结论:MiR-211及LARP1在胃癌组织中呈高表达,VGLL4呈低表达,和胃癌生物学行为相关,可能成为胃癌诊治的潜在生物学指标。展开更多
文摘The La (SS-B) autoimmune antigen is an RNA-binding protein that is present in both nucleus and cytoplasm of eukaryotic cells.The spectrum of RNAs that interact with the antigen includes species which also bind to the interferon-inducible protein kinase PKR.We have investigated whether the La antigen can regulate the activity of PKR and have observed that both the autophosphorylation of the protein kinase that accompanies its activation by dsRNA and the dsRNA-dependent phosphorylation of the subunit of polypeptide chain initiation factor eIF-2 by PKR are inhibited in the presence of recombinant La antigen. This inhibition is partially relieved at higher concentrations of dsRNA.Once activated by dsRNA the protein kinase activity of PKR is insensitive to the La antigen. We have demonstrated by a filter binding assay that La is a dsRNA binding protein.Furthermore, when recombinant La is incubated with a 900bp synthetic dsRNA or with naturally occurring reovirus dsRNA it converts these substrates to single-stranded forms.We conclude that the La antigen inhibits the dsRNA-dependent activation of PKR by binding and unwinding dsRNA and that it may therefore play a role in the regulation of this protein kinase in interferon-treated or virus-infected cells.
文摘以新城疫病毒(Newcastlediseace virus,NDV)La sota F蛋白的氨基酸序列为基础,采用Chou-Fasman法、Garnier-Robson法、Karplus-Schulz法与Kyte-Doolittle法、Emini法和Jameson-Wolf法分别预测蛋白质的二级结构和B细胞抗原表位。预测结果表明,NDV La Sota F蛋白结构较为复杂,含有较多的α-螺旋、β-折叠区,转角和无规则卷曲等有柔韧性区域。此外,应用Tmap法预测了NDV La sota F蛋白的跨膜区域,通过同源建模的方法预测了该蛋白的三维空间结构,并比较了强弱毒株裂解位点处空间结构的不同。为进一步通过试验方法确定其蛋白的B细胞表位和从结构出发了解其生物学功能,提供了理论依据。
文摘目的:分析微小核糖核酸-211(micro ribonucleic acid-211,miR-211)、La相关蛋白1(La-associated protein 1,LARP1)、转录辅助因子退变样蛋白4(transcription-assisted factor deformable protein 4,VGLL4)在胃癌组织中的表达及意义。方法:收集98例胃癌患者,并取胃癌组织距离肿瘤边缘5 cm的癌旁组织43例。比较胃癌组织和癌旁组织miR-211,LARP1,VGLL4表达情况和以上指标与胃癌患者临床病理特征及生存情况的关系。结果:胃癌患者miR-211及LARP1高表达率高于癌旁组织,VGLL4高表达率低于癌旁组织(均P<0.05)。MiR-211,LARP1,VGLL4表达在TNM分期、淋巴结转移、浸润深度中差异有统计学意义(P<0.05)。MiR-211及LARP1高表达者3年生存率分别低于miR-211及LARP1低表达者,VGLL4高表达者3年生存率高于低表达者(P<0.05)。Cox比例风险模型分析显示TNM分期、淋巴结转移、浸润深度、miR-211、LARP1为胃癌预后的危险因素,VGLL4为保护因素。miR-211与LARP1呈正相关,miR-211与VGLL4,LARP1与VEGLL4呈负相关。结论:MiR-211及LARP1在胃癌组织中呈高表达,VGLL4呈低表达,和胃癌生物学行为相关,可能成为胃癌诊治的潜在生物学指标。
