Reijo R A, Cho D S, Huffaker T C
Section of Biochemistry, Molecular and Cell Biology, Cornell University, Ithaca, New York 14853.
Genetics. 1993 Dec;135(4):955-62. doi: 10.1093/genetics/135.4.955.
rts1-1 was identified as an extragenic suppressor of tub2-104, a cold-sensitive allele of the sole gene encoding beta-tubulin in the yeast, Saccharomyces cerevisiae. In addition, rts1-1 cells are heat sensitive and resistant to the microtubule-destabilizing drug, benomyl. The rts1-1 mutation is a deletion of approximately 5 kb of genomic DNA on chromosome X that includes one open reading frame and three tRNA genes. Dissection of this region shows that heat sensitivity is due to deletion of the open reading frame (HIT1). Suppression and benomyl resistance are caused by deletion of the gene encoding a tRNA(Arg)AGG (HSX1). Northern analysis of rts1-1 cells indicates that HSX1 is the only gene encoding this tRNA. Deletion of HSX1 does not suppress the tub2-104 mutation by misreading at the AGG codons in TUB2. It also does not suppress by interfering with the protein arginylation that targets certain proteins for degradation. These results leave open the prospect that this tRNA(Arg)AGG plays a novel role in the cell.
rts1-1被鉴定为tub2-104的基因外抑制子，tub2-104是酿酒酵母中编码β-微管蛋白的唯一基因的一个冷敏感等位基因。此外，rts1-1细胞对热敏感且对微管破坏药物苯菌灵具有抗性。rts1-1突变是X染色体上约5 kb基因组DNA的缺失，其中包括一个开放阅读框和三个tRNA基因。对该区域的分析表明，热敏感性是由于开放阅读框（HIT1）的缺失所致。抑制作用和苯菌灵抗性是由编码tRNA(Arg)AGG（HSX1）的基因缺失引起的。对rts1-1细胞的Northern分析表明，HSX1是编码这种tRNA的唯一基因。HSX1的缺失不会通过误读TUB2中的AGG密码子来抑制tub2-104突变。它也不会通过干扰将某些蛋白质靶向降解的蛋白质精氨酸化来抑制。这些结果留下了这种tRNA(Arg)AGG在细胞中发挥新作用的可能性。
