多嘧啶序列结合蛋白在丙型肝炎病毒和微小核糖核酸病毒RNA内部起始中的作用的比较研究

Comparative aspects on the role of polypyrimidine tract-binding protein in internal initiation of hepatitis C virus and picornavirus RNAs.

作者信息

Nishimura T, Saito M, Takano T, Nomoto A, Kohara M, Tsukiyama-Kohara K

机构信息

Department of Experimental Phylaxiology, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University 1-1-1, Honjo, Kumamoto 860-8556, Japan.

出版信息

Comp Immunol Microbiol Infect Dis. 2008 Sep;31(5):435-48. doi: 10.1016/j.cimid.2007.07.002. Epub 2007 Aug 15.

DOI:10.1016/j.cimid.2007.07.002

PMID:17706779

Abstract

We compared the effects of polypyrimidine tract-binding protein (PTB) on hepatitis C virus (HCV genotype IIa), encephalomyocarditis virus (EMCV) and poliovirus internal ribosome entry site (IRES) activities in vitro. It bound strongly to EMCV IRES, but weakly to PV and HCV RNAs. PV IRES showed the strongest dependency to PTB and it showed less than one-tenth of IRES activity after the immuno-depletion of PTB from HeLa S10 lysate with pre-coated anti-PTB IgG beads, comparing to the normal IgG beads-treated S10 lysate. EMCV IRES activity was approximately 40% of that of normal control after PTB depletion. Especially, HCV IRES activity was approximately 95%, and most weekly affected by the depletion of PTB. Repletion of PTB to depleted S10 lysate restored activities of PV and EMCV IRESs. The data suggest that PTB plays an important role in picornaviral IRESs, but not in HCV IRES.

摘要

我们在体外比较了多嘧啶序列结合蛋白（PTB）对丙型肝炎病毒（HCV 基因 IIa 型）、脑心肌炎病毒（EMCV）和脊髓灰质炎病毒内部核糖体进入位点（IRES）活性的影响。它与 EMCV IRES 结合紧密，但与脊髓灰质炎病毒（PV）和 HCV 的 RNA 结合较弱。PV IRES 对 PTB 的依赖性最强，在用预包被的抗 PTB IgG 磁珠从 HeLa S10 裂解物中免疫去除 PTB 后，其 IRES 活性与正常 IgG 磁珠处理的 S10 裂解物相比降低至不到十分之一。PTB 耗尽后，EMCV IRES 活性约为正常对照的 40%。特别是，HCV IRES 活性约为 95%，且受 PTB 耗尽的影响最小。向耗尽 PTB 的 S10 裂解物中补充 PTB 可恢复 PV 和 EMCV IRES 的活性。数据表明，PTB 在小核糖核酸病毒 IRES 中起重要作用，但在 HCV IRES 中并非如此。