POLY(A)-BINDING PROTEIN-RNA COMPLEX

这个子项目是利用资源的许多研究子项目之一。 由NIH/NCRR资助的中心拨款提供。对子项目的主要支持 子项目的首席调查员可能是由其他来源提供的， 包括美国国立卫生研究院的其他来源。为子项目列出的总成本可能 表示该子项目使用的中心基础设施的估计数量， 不是由NCRR赠款提供给次级项目或次级项目工作人员的直接资金。 Poly(A)结合蛋白(PABP)是一种重要的调节蛋白，同时控制着mRNA的翻译和降解。PABP结合Poly(A)RNA，并沿着Poly(A)尾部组织成未定义的寡聚化结构，以重复的27-NT模式保护mRNA免受核酸酶的影响。PABP有四个RRM基序与RNA结合。RRM1-2与7种腺苷形成复合体。C-末端结构域是个谜。它富含脯氨酸和丙氨酸，几乎是其分子的一半。在末端有一个小的球状结构域，其结构被核磁共振解析，并含有与翻译释放因子3(ERF3)、PABP调节蛋白(PAIP2)和聚(A)核酸酶(Pan3)相互作用的结合裂隙。C-末端结构域的其他较不明确的区域结合60S核糖体、启动因子(EIF4B)、翻译刺激因子(PAIP1)和ataxin2。 长期目标是确定PABP与eIF4G和eRF3的相互作用如何调节从头翻译的启动，而不是核糖体3‘-5’循环。另一个长期目标是了解选择的PABP部分(由交替构象指导)的切割如何能够关闭脊髓灰质炎病毒的mRNA翻译，并同时激活同一模板上的病毒RNA复制。这涉及病毒3CD(RNA聚合酶前体)、病毒5‘三叶草结构上的PCBP2(细胞RNA结合蛋白)和Poly(A)尾部的PABP之间的5’-3相互作用。病毒RNA合成的起始不是在PolyA尾部的3‘端，而是在内部，从3’非翻译区的3‘端开始的20个核苷酸(3)。我们假设一个PABP被用作将聚合酶放置在模板上的分子工具。然而，为什么沿着聚(A)尾部的3-4个潜在的PABP部分中的一个被选择作为定向切割和聚合酶访问模板的分子标记，这是没有道理的

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Poly(A)-binding protein (PABP) is a critical regulatory protein that simultaneously controls mRNA translation and decay. PABP binds poly(A) RNA and organizes into undefined oligomerized structures along poly(A) tails that protect mRNA from nucleases in a repeating 27-nt pattern. PABP has four RRM motifs that bind RNA. A structure exists for RRM1-2 complexed with 7 adenylates. The C-terminal domain is enigmatic. It is proline and alanine-rich and nearly half the molecule. There is a small globular domain at the extreme C-terminus whose structure was solved by NMR, and contains a binding cleft for interactions with translation release factor 3(eRF3), and PABP regulatory protein (PAIP2), and poly(A)nuclease (Pan3). Other less defined regions of the C-terminal domain bind 60S ribosomes, initiation factors (eIF4B), translation stimulatory factors (Paip1) and ataxin2. Long term goals are to determine how interactions of PABP with eIF4G and eRF3 regulate de novo translation initiation versus ribosome 3'-5' recycling. Another long term goal is to understand how cleavage of select PABP moieties (directed by alternate conformations), is able to shut off poliovirus mRNA translation and simultaneously activate viral RNA replication on the same template. This is known to involve 5' -3 interactions between viral 3CD (RNA polymerase precursor), PCBP2 (cellular RNA-binding protein) on the viral 5' cloverleaf structure and PABP on the poly(A) tail. Viral RNA synthesis initiation occurs not at the 3' end of the poly(A) tail, but internally, 20 nucleotides from the 3' end of the 3' untranslated region (3). We hypothesize that one PABP is used as a molecular tool for polymerase placement on the template. However, there is no rationale for how one of 3-4 potential PABP moieties along the poly(A) tail is chosen as a molecular marker for directed cleavage and polymerase access to the template