Polypyrimidine tract binding protein functions as a negative regulator of feline calicivirus translation.
Polypyrimidine tract binding protein functions as a negative regulator of feline calicivirus translation.
复制标题
DOI：
10.1371/journal.pone.0009562
复制
发表时间：
2010-03-10
期刊：
影响因子：
3.7
通讯作者：
Goodfellow IG
中科院分区：
文献类型：
--
作者：
Karakasiliotis I;Vashist S;Bailey D;Abente EJ;Green KY;Roberts LO;Sosnovtsev SV;Goodfellow IG
正链RNA病毒在其生命周期的各个方面严重依赖于宿主细胞RNA结合蛋白。这些蛋白质与通常存在于病毒RNA基因组的5′或3′末端的序列相互作用，以调节病毒翻译和/或复制。我们以前报道过，已被充分表征的宿主RNA结合蛋白多聚嘧啶束结合蛋白（PTB）与猫杯状病毒（FCV）基因组和亚基因组RNA的5′端相互作用，在FCV的生命周期中发挥作用。我们已经证明PTB与FCV基因组5′端内的至少两个结合位点相互作用。体外翻译表明，PTB可以作为FCV翻译的负调节剂起作用，并且这随后被证实为在PTB siRNA处理的细胞中病毒亚基因组RNA的翻译在RNA复制不能发生的条件下被刺激。我们还观察到PTB在FCV感染期间从细胞核重新分布到细胞质，部分定位于病毒复制复合物，表明PTB结合可能参与从翻译到复制的转换。反向遗传学研究表明，PTB结合位点的同义突变导致FCV复制中的细胞类型特异性缺陷。我们的数据表明，PTB可能起到负调控FCV翻译起始的作用。为了调和这与有效的病毒在细胞中复制，我们提出了一个假定的模型PTB在FCV生命周期中的功能。在感染的早期阶段，病毒RNA可能在没有PTB的情况下被翻译，然而，随着病毒蛋白质水平的增加，PTB的核质穿梭被改变，增加PTB的细胞质水平，抑制病毒翻译。PTB是否直接抑制翻译起始或通过募集其他因子仍有待确定，但这可能有助于通过清除病毒RNA中的核糖体刺激病毒RNA复制。
Positive strand RNA viruses rely heavily on host cell RNA binding proteins for various aspects of their life cycle. Such proteins interact with sequences usually present at the 5′ or 3′ extremities of the viral RNA genome, to regulate viral translation and/or replication. We have previously reported that the well characterized host RNA binding protein polypyrimidine tract binding protein (PTB) interacts with the 5′end of the feline calicivirus (FCV) genomic and subgenomic RNAs, playing a role in the FCV life cycle. We have demonstrated that PTB interacts with at least two binding sites within the 5′end of the FCV genome. In vitro translation indicated that PTB may function as a negative regulator of FCV translation and this was subsequently confirmed as the translation of the viral subgenomic RNA in PTB siRNA treated cells was stimulated under conditions in which RNA replication could not occur. We also observed that PTB redistributes from the nucleus to the cytoplasm during FCV infection, partially localizing to viral replication complexes, suggesting that PTB binding may be involved in the switch from translation to replication. Reverse genetics studies demonstrated that synonymous mutations in the PTB binding sites result in a cell-type specific defect in FCV replication. Our data indicates that PTB may function to negatively regulate FCV translation initiation. To reconcile this with efficient virus replication in cells, we propose a putative model for the function of PTB in the FCV life cycle. It is possible that during the early stages of infection, viral RNA is translated in the absence of PTB, however, as the levels of viral proteins increase, the nuclear-cytoplasmic shuttling of PTB is altered, increasing the cytoplasmic levels of PTB, inhibiting viral translation. Whether PTB acts directly to repress translation initiation or via the recruitment of other factors remains to be determined but this may contribute to the stimulation of viral RNA replication via clearance of ribosomes from viral RNA.
登录
查看更多内容
影响因子：
10.5
作者：
Besse, Florence;de Quinto, Sonia Lopez;Ephrussi, Anne
通讯作者：
Ephrussi, Anne
影响因子：
5.4
作者：
Green, KY;Mory, A;Sosnovtsev, SV
通讯作者：
Sosnovtsev, SV
影响因子：
5.3
作者：
Castelo-Branco, P;Furger, A;Proudfoot, N
通讯作者：
Proudfoot, N
影响因子：
4.8
作者：
Chaudhry, Yasmin;Nayak, Arabinda;Goodfellow, Ian G.
通讯作者：
Goodfellow, Ian G.
影响因子：
3.8
作者：
Al-Molawi, N;Beardmore, VA;Roberts, LO
通讯作者：
Roberts, LO