Essential roles of Bdp1, a subunit of RNA polymerase III initiation factor TFIIIB, in transcription and tRNA processing
Essential roles of Bdp1, a subunit of RNA polymerase III initiation factor TFIIIB, in transcription and tRNA processing
复制标题
DOI：
10.1128/mcb.22.10.3264-3275.2002
复制
发表时间：
2002-05-01
影响因子：
5.3
通讯作者：
Geiduschek, EP
中科院分区：
文献类型：
--
作者：
Ishiguro, A;Kassavetis, GA;Geiduschek, EP
酿酒酵母必需基因BDP1编码RNA聚合酶III （Pol il）转录因子（TFTIIIB）的一个亚基；TATA盒结合蛋白（TBP）和Brf1是该三蛋白复合物的其他亚基。缺失分析确定了Bdp1的三个片段，它们对生存能力至关重要。由氨基酸327至353组成的中心片段被发现是必不可少的，并且在氨基酸352处分裂的细胞产生Bdp1是可以存活的。通过过表达SPT15和BRF1抑制bdp1条件活性，分别鉴定了bdp1特定片段与TBP和BRF1的功能相互作用。在TFIIIC的Tfc4 （tau(131)）亚基的第二个四肽重复基序（共11个）中，PCF1-1的过表达导致了Bdp1缺失的合成致死性。该分析还确定了Bdp1与Pol III转录物转录后加工之间的联系。酵母基因组文库筛选发现，由于缺失Bdp1氨基酸253 ~ 269，RPR1是37℃下生长非常缓慢的特异性过表达抑制因子。RPR1 RNA是一种Pol III转录物，是RNase P的RNA亚基，负责修剪前trna转录物5'端。在bdpl-Delta253-269细胞中发现tRNA的成熟异常，并且当重组Bdp1Delta253-269取代野生型Bdp1时，体外高分辨率Pol III转录系统的RPR1转录也减少。RNase P与Bdp1的物理相互作用通过共免疫沉淀和拉下实验得到证实。
The essential Saccharomyces cerevisiae gene BDP1 encodes a subunit of RNA polymerase III (Pol IIl) transcription factor (TFTIIIB); TATA box binding protein (TBP) and Brf1 are the other subunits of this three-protein complex. Deletion analysis defined three segments of Bdp1 that are essential for viability. A central segment, comprising amino acids 327 to 353, was found to be dispensable, and cells making Bdp1 that was split within this segment, at amino acid 352, are viable. Suppression of bdp1 conditional viability by overexpressing SPT15 and BRF1 identified functional interactions of specific Bdp1 segments with TBP and Brf1, respectively. A Bdp1 deletion near essential segment I was synthetically lethal with overexpression of PCF1-1, a dominant gain-of-function mutation in the second tetracopeptide repeat motif (out of 11) of the Tfc4 (tau(131)) subunit of TFIIIC. The analysis also identifies a connection between Bdp1 and posttranscriptional processing of Pol III transcripts. Yeast genomic library screening identified RPR1 as the specific overexpression suppressor of very slow growth at 37 C due to deletion of Bdp1 amino acids 253 to 269. RPR1 RNA, a Pol III transcript, is the RNA subunit of RNase P, which trims pre-tRNA transcript 5' ends. Maturation of tRNA was found to be aberrant in bdpl-Delta253-269 cells, and RPR1 transcription with the highly resolved Pol III transcription system in vitro was also diminished when recombinant Bdp1Delta253-269 replaced wild-type Bdp1. Physical interaction of RNase P with Bdp1 was demonstrated by coimmunoprecipitation and pull-down assays.