Molecular population genetics and evolution of a prion-like protein in Saccharomyces cerevisiae.
Molecular population genetics and evolution of a prion-like protein in Saccharomyces cerevisiae.
复制标题
酿酒酵母中朊病毒样蛋白的分子群体遗传学和进化。
DOI：
10.1093/genetics/159.2.527
复制
发表时间：
2001
期刊：
影响因子：
3.3
通讯作者：
Lindquist,S
中科院分区：
文献类型：
--
作者：
Jensen,MA;True,HL;Chernoff,YO;Lindquist,S
The prion-like behavior of Sup35p, the eRF3 homolog in the yeastSaccharomyces cerevisiae, mediates the activity of the cytoplasmic nonsense suppressor known as [PSI+]. Sup35p is divided into three regions of distinct function. The N-terminal and middle (M) regions are required for the induction and propagation of [PSI+] but are not necessary for translation termination or cell viability. The C-terminal region encompasses the termination function. The existence of the N-terminal region inSUP35homologs of other fungi has led some to suggest that this region has an adaptive function separate from translation termination. To examine this hypothesis, we sequenced portions ofSUP35in 21 strains ofS. cerevisiae, including 13 clinical isolates. We analyzed nucleotide polymorphism within this species and compared it to sequence divergence from a sister species,S. paradoxus. The N domain of Sup35p is highly conserved in amino acid sequence and is highly biased in codon usage toward preferred codons. Amino acid changes are under weak purifying selection based on a quantitative analysis of polymorphism and divergence. We also conclude that the clinical strains ofS. cerevisiaeare not recently derived and that outcrossing between strains inS. cerevisiaemay be relatively rare in nature.
