CEA, iBiTec-S, Service de Biologie Intégrative & Génétique Moléculaire, F-91191 Gif-sur-Yvette, France.
FEBS Lett. 2011 Nov 4;585(21):3355-9. doi: 10.1016/j.febslet.2011.09.011. Epub 2011 Oct 4.
An Rpa43/Rpa14 stalk protrudes from RNA polymerase I (RNAPI), with homology to Rpb7/Rpb4 (RNAPII), Rpc25/Rpc17 (RNAPIII) and RpoE/RpoF (archaea). In fungi and vertebrates, Rpa43 contains hydrophilic domains forming about half of its size, but these domains lack in Schizosaccharomyces pombe and most other eukaryote lineages. In Saccharomyces cerevisiae, they can be lost with little or no growth effect, as shown by deletion mapping and by domain swapping with fission yeast, but genetically interact with rpa12Δ, rpa34Δ or rpa49Δ, lacking non-essential subunits important for transcript elongation. Two-hybrid data and other genetic evidence suggest that Rpa43 directly bind Spt5, an RNAPI elongation factor also acting in RNAPII-dependent transcription, and may also interact with the nucleosomal chaperone Spt6.
Rpa43/Rpa14 柄突伸出 RNA 聚合酶 I（RNAPI），与 RNAPII 的 Rpb7/Rpb4、RNAPIII 的 Rpc25/Rpc17 和古菌的 RpoE/RpoF 同源。在真菌和脊椎动物中，Rpa43 包含形成其大小约一半的亲水结构域，但这些结构域在裂殖酵母和大多数其他真核生物谱系中缺失。在酿酒酵母中，正如通过缺失作图和与裂殖酵母的结构域交换所表明的，缺失它们几乎没有或没有生长影响，但与 rpa12Δ、rpa34Δ 或 rpa49Δ 遗传相互作用，这些缺失对转录延伸很重要的非必需亚基。双杂交数据和其他遗传证据表明，Rpa43 直接结合 Spt5，这是一种 RNAPI 延伸因子，也在 RNAPII 依赖性转录中起作用，并且可能还与核小体伴侣 Spt6 相互作用。
