Meiotic gene conversion mutants in Saccharomyces cerevisiae. I. Isolation and characterization of pms1-1 and pms1-2.
Meiotic gene conversion mutants in Saccharomyces cerevisiae. I. Isolation and characterization of pms1-1 and pms1-2.
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DOI：
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发表时间：
1985-08
期刊：
影响因子：
3.3
通讯作者：
M. S. Williamson;J. Game;S. Fogel
中科院分区：
文献类型：
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作者：
M. S. Williamson;J. Game;S. Fogel
pms1 突变体是根据两个紧密相连的 his4 等位基因的减数分裂原养细胞频率急剧升高而分离出来的，在减数分裂和有丝分裂细胞中显示出多效性表型。对两个携带 PMS1 隐性突变的分离株进行了鉴定。他们确定了在许多杂合位点维持低减数分裂后分离（PMS）频率所需的功能。此外，它们是有丝分裂突变体。在突变二倍体中，孢子活力降低，在幸存者中，基因转换和减数分裂后分离频率增加，但相互交换频率不受影响。 pms1 纯合子中多重标记区域的转换事件模式也发生了显着变化。 PMS1 基因座位于 XIV 染色体上的 MET4 附近。 PMS1基因可以识别切除-再合成长斑错配校正功能或促进校正束伸长的功能。 PMS1 基因产物也可能在避免自发有丝分裂突变和纠正自发和紫外线诱导的有丝分裂重组过程中形成的异源双链 DNA 错配方面发挥重要作用。基于强调异源双链 DNA 中间体错配校正的减数分裂重组模型，这种解释受到青睐，但也考虑涉及突变体中较长重组中间体的替代解释。
The pms1 mutants, isolated on the basis of sharply elevated meiotic prototroph frequencies for two closely linked his4 alleles, display pleiotropic phenotypes in meiotic and mitotic cells. Two isolates carrying recessive mutations in PMS1 were characterized. They identify a function required to maintain low postmeiotic segregation (PMS) frequencies at many heterozygous sites. In addition, they are mitotic mutators. In mutant diploids, spore viability is reduced, and among survivors, gene conversion and postmeiotic segregation frequencies are increased, but reciprocal exchange frequencies are not affected. The conversion event pattern is also dramatically changed in multiply marked regions in pms1 homozygotes. The PMS1 locus maps near MET4 on chromosome XIV. The PMS1 gene may identify an excision-resynthesis long patch mismatch correction function or a function that facilitates correction tract elongation. The PMS1 gene product may also play an important role in spontaneous mitotic mutation avoidance and correction of mismatches in heteroduplex DNA formed during spontaneous and UV-induced mitotic recombination. Based on meiotic recombination models emphasizing mismatch correction in heteroduplex DNA intermediates, this interpretation is favored, but alternative interpretations involving longer recombination intermediates in the mutants are also considered.