A mutation in the second largest subunit of TFIIIC increases a rate-limiting step in transcription by RNA polymerase III.
A mutation in the second largest subunit of TFIIIC increases a rate-limiting step in transcription by RNA polymerase III.
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TFIIIC 第二大亚基的突变增加了 RNA 聚合酶 III 转录的限速步骤。
DOI：
10.1128/mcb.14.1.822-830.1994
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发表时间：
1994
影响因子：
5.3
通讯作者：
Willis,I
中科院分区：
文献类型：
--
作者：
Rameau,G;Puglia,K;Crowe,A;Sethy,I;Willis,I
In previous studies, we have shown that thePCF1-1mutation ofSaccharomyces cerevisiaesuppresses the negative effect of a tRNA gene A block promoter mutation in vivo and increases the transcription of a variety of RNA polymerase III genes in vitro. Here, we report thatPCF1encodes the second largest subunit of transcription factor IIIC (TFIIIC) and that thePCF1-1mutation causes an amino acid substitution in a novel protein structural motif, a tetratricopeptide repeat, in this subunit. In agreement with the nature of the mutation, in vitro transcription studies with crude extracts indicate thatPCF1-1facilitates the rate-limiting step in transcription, namely, the recruitment of TFIIIB to the template. Additionally, biochemical fractionation of wild-type and mutant cell extracts shows thatPCF1-1increases the amount of the 70-kDa TFIIIB subunit detectable by Western (immunoblot) analysis in purified TFIIIB fractions and the transcription activity of a TFIIIB” fraction containing the 90-kDa subunit of this factor. We suggest that the effect ofPCF1-1on TFIIIB activity in vitro is a consequence of its increased rate of recruitment in vivo.
