Genetic characterization of the Saccharomyces cerevisiae translational initiation suppressors sui1, sui2 and SUI3 and their effects on HIS4 expression.
Genetic characterization of the Saccharomyces cerevisiae translational initiation suppressors sui1, sui2 and SUI3 and their effects on HIS4 expression.
复制标题
酿酒酵母翻译起始抑制子 sui1、sui2 和 SUI3 的遗传特征及其对 HIS4 表达的影响。
DOI：
10.1093/genetics/124.3.483
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发表时间：
1990
期刊：
影响因子：
3.3
通讯作者：
Donahue,TF
中科院分区：
文献类型：
--
作者：
Castilho-Valavicius,B;Yoon,H;Donahue,TF
通过回归分析研究了含有 HIS4 翻译起始 AUG 密码子突变的酿酒酵母菌株，试图鉴定可能在扫描过程中参与起始位点选择的翻译起始复合物的成分。这些回复体的遗传特征确定了三个不连锁的抑制基因座：SUI1、SUI2 和 sui3，尽管不存在 AUG 起始密码子，但它们在突变时恢复了 HIS4 等位基因的表达。 sui1 和 sui2 都是隐性的，在富集培养基上会引起温度敏感的生长。与 sui1 或 sui2 突变相关的温度敏感表型和恢复 HIS4 表达的能力在杂交中共分离。 SUI3 突变占主导地位，不会改变生长的热分布。三个基因座的突变均不会抑制已知的移码、错义或无义突变。每一种都能够抑制 HIS4 或 HIS4-lacZ 起始密码子的九个不同点突变，以及 AUG 密码子的两碱基变化 (ACC) 和三碱基删除，表明抑制位点位于正常起始区域之外。 sui1 和 sui2 抑制突变分别映射到 XIV 和 X 染色体。 sui1、sui2 和 SUI3 突变的抑制导致缺乏起始 AUG 密码子的 HIS4 等位基因的表达相对于同基因亲本菌株分别增加 14、11 和 47 倍。 sui2 和 SUI3 导致的 HIS4 表达增加的部分原因可归因于 HIS4 mRNA 水平的增加，这可能是由酵母一般氨基酸控制系统的扰动介导的。
Saccharomyces cerevisiae strains containing mutations of the HIS4 translation initiation AUG codon were studied by reversion analysis in an attempt to identify components of the translation initiation complex that might participate in initiation site selection during the scanning process. The genetic characterization of these revertants identified three unlinked suppressor loci: SUI1, SUI2 and sui3, which when mutated restored the expression of the HIS4 allele despite the absence of the AUG initiator codon. Both sui1 and sui2 are recessive and cause temperature-sensitive growth on enriched medium. The temperature-sensitive phenotype and the ability to restore HIS4 expression associated with either sui1 or sui2 mutations cosegregate in crosses. SUI3 mutations are dominant and do not alter the thermal profile for growth. None of the mutations at the three loci suppresses known frameshift, missense or nonsense mutations. Each is capable of suppressing the nine different point mutations of the initiator codon at HIS4 or HIS4-lacZ as well as a two base change (ACC) and a three base deletion of the AUG codon, suggesting that the site of suppression resides outside the normal initiator region. sui1 and sui2 suppressor mutations were mapped to chromosomes XIV and X, respectively. Suppression by sui1, sui2 and SUI3 mutations results in 14-, 11- and 47-fold increases, respectively, relative to isogenic parent strains, in the expression of a HIS4 allele lacking the initiator AUG codon. Part of this increase in the HIS4 expression by sui2 and SUI3 can be attributed to increases of HIS4 mRNA levels, presumably mediated by perturbation of the general amino acid control system of yeast.