共查询到20条相似文献,搜索用时 31 毫秒
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Rojas DA Moreira-Ramos S Zock-Emmenthal S Urbina F Contreras-Levicoy J Käufer NF Maldonado E 《The Journal of biological chemistry》2011,286(30):26480-26486
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Functional architecture of RNA polymerase I 总被引:1,自引:0,他引:1
Kuhn CD Geiger SR Baumli S Gartmann M Gerber J Jennebach S Mielke T Tschochner H Beckmann R Cramer P 《Cell》2007,131(7):1260-1272
Synthesis of ribosomal RNA (rRNA) by RNA polymerase (Pol) I is the first step in ribosome biogenesis and a regulatory switch in eukaryotic cell growth. Here we report the 12 A cryo-electron microscopic structure for the complete 14-subunit yeast Pol I, a homology model for the core enzyme, and the crystal structure of the subcomplex A14/43. In the resulting hybrid structure of Pol I, A14/43, the clamp, and the dock domain contribute to a unique surface interacting with promoter-specific initiation factors. The Pol I-specific subunits A49 and A34.5 form a heterodimer near the enzyme funnel that acts as a built-in elongation factor and is related to the Pol II-associated factor TFIIF. In contrast to Pol II, Pol I has a strong intrinsic 3'-RNA cleavage activity, which requires the C-terminal domain of subunit A12.2 and, apparently, enables ribosomal RNA proofreading and 3'-end trimming. 相似文献
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Albert B Léger-Silvestre I Normand C Ostermaier MK Pérez-Fernández J Panov KI Zomerdijk JC Schultz P Gadal O 《The Journal of cell biology》2011,192(2):277-293
RNA polymerase I (Pol I) produces large ribosomal RNAs (rRNAs). In this study, we show that the Rpa49 and Rpa34 Pol I subunits, which do not have counterparts in Pol II and Pol III complexes, are functionally conserved using heterospecific complementation of the human and Schizosaccharomyces pombe orthologues in Saccharomyces cerevisiae. Deletion of RPA49 leads to the disappearance of nucleolar structure, but nucleolar assembly can be restored by decreasing ribosomal gene copy number from 190 to 25. Statistical analysis of Miller spreads in the absence of Rpa49 demonstrates a fourfold decrease in Pol I loading rate per gene and decreased contact between adjacent Pol I complexes. Therefore, the Rpa34 and Rpa49 Pol I-specific subunits are essential for nucleolar assembly and for the high polymerase loading rate associated with frequent contact between adjacent enzymes. Together our data suggest that localized rRNA production results in spatially constrained rRNA production, which is instrumental for nucleolar assembly. 相似文献
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The yeast transcription elongation factor Spt4/5 is a sequence‐specific RNA binding protein
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Amanda J. Blythe Berra Yazar‐Klosinski Michael W. Webster Eefei Chen Marylène Vandevenne Katerina Bendak Joel P. Mackay Grant A. Hartzog Alice Vrielink 《Protein science : a publication of the Protein Society》2016,25(9):1710-1721
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