Guéguéniat Julia, Dupin Adrien F, Stojko Johan, Beaurepaire Lionel, Cianférani Sarah, Mackereth Cameron D, Minvielle-Sébastia Lionel, Fribourg Sébastien
Université de Bordeaux, INSERM U1212, CNRS UMR5320, Bordeaux, France.
Laboratoire de Spectrométrie de Masse BioOrganique, Université de Strasbourg, CNRS, IPHC UMR 7178, 67000 Strasbourg, France.
Nucleic Acids Res. 2017 Sep 29;45(17):10115-10131. doi: 10.1093/nar/gkx674.
New transcripts generated by RNA polymerase II (RNAPII) are generally processed in order to form mature mRNAs. Two key processing steps include a precise cleavage within the 3' end of the pre-mRNA, and the subsequent polymerization of adenosines to produce the poly(A) tail. In yeast, these two functions are performed by a large multi-subunit complex that includes the Cleavage Factor IA (CF IA). The four proteins Pcf11, Clp1, Rna14 and Rna15 constitute the yeast CF IA, and of these, Pcf11 is structurally the least characterized. Here, we provide evidence for the binding of two Zn2+ atoms to Pcf11, bound to separate zinc-binding domains located on each side of the Clp1 recognition region. Additional structural characterization of the second zinc-binding domain shows that it forms an unusual zinc finger fold. We further demonstrate that the two domains are not mandatory for CF IA assembly nor RNA polymerase II transcription termination, but are rather involved to different extents in the pre-mRNA 3'-end processing mechanism. Our data thus contribute to a more complete understanding of the architecture and function of Pcf11 and its role within the yeast CF IA complex.
RNA聚合酶II（RNAPII）产生的新转录本通常需要经过加工才能形成成熟的mRNA。两个关键的加工步骤包括在前体mRNA的3'端进行精确切割，以及随后腺苷酸聚合形成聚腺苷酸尾巴。在酵母中，这两种功能由一个大型多亚基复合物执行，该复合物包括切割因子IA（CF IA）。Pcf11、Clp1、Rna14和Rna15这四种蛋白质构成了酵母CF IA，其中Pcf11在结构上的特征最少。在这里，我们提供了证据表明两个Zn2+原子与Pcf11结合，它们分别结合在Clp1识别区域两侧的不同锌结合结构域上。对第二个锌结合结构域的进一步结构表征表明，它形成了一种不寻常的锌指结构。我们进一步证明这两个结构域对于CF IA组装和RNA聚合酶II转录终止不是必需的，而是在不同程度上参与前体mRNA 3'端加工机制。因此，我们的数据有助于更全面地了解Pcf11及其在酵母CF IA复合物中的作用的结构和功能。
