Cell cycle regulation of hepatitis C virus internal ribosomal entry site-directed translation
Cell cycle regulation of hepatitis C virus internal ribosomal entry site-directed translation
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DOI：
10.1016/s0016-5085(00)70424-0
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发表时间：
2000-01-01
期刊：
影响因子：
29.4
通讯作者：
Lemon, SM
中科院分区：
文献类型：
--
作者：
Honda, M;Kaneko, S;Lemon, SM
背景和目标：丙型肝炎病毒（HCV）多聚蛋白的翻译由位于病毒RNA的5'非翻译区段内的内部核糖体进入位点（IRES）介导。已知该RNA区段在体外与分离的40 S核糖体亚基形成二元复合物，但对病毒翻译过程如何在体内调节了解甚少。我们从Huh-7细胞中建立了2个稳定转化的细胞系，它们组成性表达含有编码2个报告蛋白的序列的双顺反子RNA转录物（海肾荧光素酶和萤火虫荧光素酶），上游海肾荧光素酶阅读框的翻译在这些细胞中通过通常的细胞帽依赖性机制启动，而下游萤火虫荧光素酶阅读框的翻译是由IRES启动的。结果：与帽依赖性翻译相比，IRES的活性在活跃生长的细胞中最大，而在静息细胞中相对降低。在这些稳定转化细胞的同步培养物中，IRES活性随细胞周期而变化，在有丝分裂（M）期最大，在静止（G（0））期最低。结论：这些研究结果表明，HCV的翻译是由细胞周期中丰度不同的细胞蛋白质调节的，并且病毒翻译可能通过刺激慢性丙型肝炎患者肝细胞再生的因素来增强。
Background & Aims: Translation of the hepatitis C virus (HCV) polyprotein is mediated by an internal ribosome entry site (IRES) that is located within the 5' nontranslated segment of the viral RNA, This RNA segment is known to form binary complexes with isolated 40S ribosome subunits in vitro, but there is little understanding of how the process of virus translation is regulated in vivo, Methods: We established 2 stably transformed cell lines from Huh-7 cells that constitutively express dicistronic RNA transcripts containing sequences encoding 2 reporter proteins (Renilla luciferase and firefiy luciferase) separated by a functional HCV IRES, The translation of the upstream Renilla luciferase reading frame is initiated in these cells by the usual cellular cap-dependent mechanism, whereas translation of the downstream firefly luciferase reading frame is initiated by the IRES, Results: Compared with cap-dependent translation, the activity of the IRES was greatest in actively growing cells and relatively reduced in resting cells. In synchronized cultures of these stably transformed cells, the IRES activity varied with the cell cycle and was greatest during the mitotic (M) phases and lowest during the quiescent (G(0)) phases. Conclusions: These findings suggest that HCV translation is regulated by cellular proteins that vary in abundance during the cell cycle and that viral translation may be enhanced by factors that stimulate the regeneration of hepatocytes in patients with chronic hepatitis C.