Mutations affecting donor preference during mating type interconversion in Saccharomyces cerevisiae.
Mutations affecting donor preference during mating type interconversion in Saccharomyces cerevisiae.
复制标题
酿酒酵母交配型互变过程中影响供体偏好的突变。
DOI：
10.1093/genetics/139.4.1495
复制
发表时间：
1995
期刊：
影响因子：
3.3
通讯作者：
Broach,JR
中科院分区：
文献类型：
--
作者：
Weiler,KS;Szeto,L;Broach,JR
通过用指定相反交配类型的信息替换在表达子基因座MAT处指定一种交配类型的遗传信息，酿酒酵母的同宗配合菌株可以将交配类型从a转换为a或从a转换为a，每一代都是如此。在MAT处复制和插入的隐蔽交配型信息包含在两个基因座HML或HMR中的任一个中。在交配型互变过程中选择作为供体的特定基因座受MAT处表达的等位基因调控。MATa细胞通常选择HML，而MAT α细胞通常选择HMR，这一过程被称为供体偏好。为了确定供体偏好所需的因素，我们分离和表征了一些突变体，这些突变体在交配型互变过程中经常选择非首选的供体位点。发现这些突变体中的许多在MAT或HML处具有干扰转换过程的染色体重排或突变。然而，一个突变体携带一个隐性等位基因CHL1，一个基因以前被证明是必需的有效的染色体分离在有丝分裂。含有CHL1无效等位基因的同宗配合的酵母菌株在MATa背景下表现出几乎随机选择供体基因座，但在MAT α背景下选择HMR的能力正常。我们的研究结果表明，Chl1p参与了供体选择的过程，并与Chl1p有助于建立供体偏好的内在偏差的模型一致。
Homothallic strains of Saccharomyces cerevisiae can convert mating type from a to alpha or alpha to a as often as every generation, by replacing genetic information specifying one mating type at the expressor locus, MAT, with information specifying the opposite mating type. The cryptic mating type information that is copied and inserted at MAT is contained in either of two loci, HML or HMR. The particular locus selected as donor during mating type interconversion is regulated by the allele expressed at MAT. MATa cells usually select HML, and MAT alpha cells usually select HMR, a process referred to as donor preference. To identify factors required for donor preference, we isolated and characterized a number of mutants that frequently selected the nonpreferred donor locus during mating type interconversion. Many of these mutants were found to harbor chromosome rearrangements or mutations at MAT or HML that interfered with the switching process. However, one mutant carried a recessive allele of CHL1, a gene previously shown to be required for efficient chromosome segregation during mitosis. Homothallic strains of yeast containing a null allele of CHL1 exhibited almost random selection of the donor locus in a MATa background but were normal in their ability to select HMR in a MAT alpha background. Our results indicate that Chl1p participates in the process of donor selection and are consistent with a model in which Chl1p helps establish an intrinsic bias in donor preference.