TAP1, a yeast gene that activates the expression of a tRNA gene with a defective internal promoter.
TAP1, a yeast gene that activates the expression of a tRNA gene with a defective internal promoter.
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TAP1，一种酵母基因，可通过有缺陷的内部启动子激活 tRNA 基因的表达。
DOI：
10.1128/mcb.13.6.3424-3433.1993
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发表时间：
1993
影响因子：
5.3
通讯作者：
Hall,BD
中科院分区：
文献类型：
--
作者：
DiSegni,G;McConaughy,BL;Shapiro,RA;Aldrich,TL;Hall,BD
我们开发了一种基于无义抑制的酿酒酵母菌遗传选择系统，以鉴定RNA聚合酶III转录起始蛋白的突变。SUP4 tRNA（Tyr）内部启动子突变（A53T61）在体内不能抑制ochre突变，在体外不能结合TFIIIC，作为选择反式代偿突变的靶标。我们在同一基因中发现了两个这样的突变，我们将其命名为tap1（转录激活蛋白）。在tap1-1突变体中，up4a53t61转录物的水平是野生型的3倍。tap1-1突变株对生长也具有温度敏感性。减数分裂连锁分析表明，热敏性状与抑制活性恢复性状共分离。在转移到限制温度后1至2小时，RNA合成在tap1-1突变体中被强烈抑制，而对蛋白质合成或生长没有任何影响。tRNA和5S rRNA的合成明显减少，不久之后，rRNA的合成受到抑制。通过对ts-生长缺陷的互补，克隆了野生型tap1基因。它是酵母生长所必需的。我们在随附的报告中显示（T. L. Aldrich， G. Di Segni， B. L. McConaughy， N. J. Keen， S. Whelen和B. D. Hall, Mol. Cell）。研究表明，tap1 /RAT1基因产物与酵母中参与poly(a)+RNA输出的RAT1基因相同，并且与酵母中另一个基因（dst2、KEM1、RAR5、SEP1或xrn1）编码的蛋白具有广泛的序列相似性，具有核酸外切酶和DNA链转移活性（review by Kearsey and Kipling [Trends Cell Biol. 1:110-112, 1991]）。
We developed a genetic selection system based on nonsense suppression inSaccharomyces cerevisiaeto identify mutations in proteins involved in transcription initiation by RNA polymerase III. A SUP4 tRNA(Tyr) internal promoter mutation (A53T61) that was unable to suppress ochre mutations in vivo and was incapable of binding TFIIIC in vitro was used as the target for selection of trans-acting compensatory mutations. We identified two such mutations in the same gene, which we namedTAP1(for transcription activation protein). The level of theSUP4A53T61transcript was threefold higher in thetap1-1mutant than in the wild type. Thetap1-1mutant strain was also temperature sensitive for growth. The thermosensitive character cosegregated with the restorer of suppression activity, as shown by meiotic linkage analysis and coreversion of the two traits. At 1 to 2 h after a shift to the restrictive temperature, RNA synthesis was strongly inhibited in thetap1-1mutant, preceding any effect upon protein synthesis or growth. A marked decrease in tRNA and 5S rRNA synthesis was seen, and shortly after that, rRNA synthesis was inhibited. By complementation of the ts- growth defect, we cloned the wild-typeTAP1gene. It is essential for yeast growth. We show in the accompanying report (T. L. Aldrich, G. Di Segni, B. L. McConaughy, N. J. Keen, S. Whelen, and B. D. Hall, Mol. Cell. Biol. 13:3434-3444, 1993) thatTAP1is identical to RAT1, a yeast gene implicated in poly(A)+RNA export and that theTAP1/RAT1 gene product has extensive sequence similarity to the protein encoded by another yeast gene (variously namedDST2, KEM1, RAR5, SEP1, orXRN1) having exonuclease and DNA strand transfer activity (reviewed by Kearsey and Kipling [Trends Cell Biol. 1:110-112, 1991]).