Zaret K S, Sherman F
Cell. 1982 Mar;28(3):563-73. doi: 10.1016/0092-8674(82)90211-2.
The cyc1-512 mutation is a 38 base pair deletion in the 3' nontranslated region of the CYC1 locus in the yeast Saccharomyces cerevisiae. The deletion occurred between two 7 bp directly repeated sequences. The cyc1-512 mutant produces approximately 10% of the normal amount of the CYC1 gene product, iso-1-cytochrome c, and produces 5%--10% of the normal steady-state amount of CYC1 mRNA. Most of the mRNAs in cyc1-512 are longer at their 3' ends by up to 1000 nucleotides, suggesting that the 38 bp deletion in cyc1-512 prevents proper transcription termination. The improper transcription termination is shown to cause converging transcription between CYC1 and an adjacent gene. The fact that all of the aberrantly sized mRNAs in cyc1-512 are polyadenylated leads us to suggest that polyadenylation may be coupled to transcription termination in yeast. We have uncovered a consensus sequence between the region deleted in cyc1-512 and the 3' nontranslated regions of some but not all yeast genes, and discuss the possible role of this sequence in transcription termination.
cyc1-512突变是酿酒酵母（Saccharomyces cerevisiae）中CYC1基因座3'非翻译区的38个碱基对缺失。该缺失发生在两个7碱基对的直接重复序列之间。cyc1-512突变体产生的CYC1基因产物异-1-细胞色素c约为正常量的10%，产生的CYC1 mRNA稳态量为正常量的5% - 10%。cyc1-512中的大多数mRNA在其3'末端延长了多达1000个核苷酸，这表明cyc1-512中的38个碱基对缺失阻止了正确的转录终止。研究表明，不正确的转录终止会导致CYC1和相邻基因之间的转录汇聚。cyc1-512中所有异常大小的mRNA都进行了多聚腺苷酸化，这一事实使我们推测多聚腺苷酸化可能与酵母中的转录终止相关。我们在cyc1-512中缺失的区域与部分（但不是全部）酵母基因的3'非翻译区之间发现了一个共有序列，并讨论了该序列在转录终止中的可能作用。
