Mating-Type Genes and MAT Switching in Saccharomyces cerevisiae
Mating-Type Genes and MAT Switching in Saccharomyces cerevisiae
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DOI：
10.1534/genetics.111.134577
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发表时间：
2012-05-01
期刊：
影响因子：
3.3
通讯作者：
Haber, James E.
中科院分区：
文献类型：
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作者：
Haber, James E.
酿酒酵母（Saccharomyces cerevisiae）的交配类型由两个非同源等位基因MATa和MAT α决定。这些序列编码了两种不同的单倍体交配类型和由它们结合形成的二倍体的调节因子。对MATa1、MAT α 1和MAT α 2等位基因的分析提供了转录激活因子和抑制因子对细胞类型的最早模型之一。值得注意的是，同型酵母细胞可以通过高度编排的位点特异性同源重组事件（用编码相反MAT等位基因的不同DNA序列取代一个MAT等位基因），每一代都可以频繁地转换交配类型。这一替换过程涉及到位于同一染色体编码MAT的两端的异色位点HML α和HMRa上的两个完整但未表达的配对型信息拷贝的参与。MAT转换的研究已经对细胞谱系的控制、基因表达的沉默、异染色质的形成以及供体序列的可及性调控产生了重要的见解。实时分析MAT开关提供了在程序性双链染色体断裂的同源重组修复过程中发生的分子事件的最详细描述。
Mating type in Saccharomyces cerevisiae is determined by two nonhomologous alleles, MATa and MAT alpha. These sequences encode regulators of the two different haploid mating types and of the diploids formed by their conjugation. Analysis of the MATa1, MAT alpha 1, and MAT alpha 2 alleles provided one of the earliest models of cell-type specification by transcriptional activators and repressors. Remarkably, homothallic yeast cells can switch their mating type as often as every generation by a highly choreographed, site-specific homologous recombination event that replaces one MAT allele with different DNA sequences encoding the opposite MAT allele. This replacement process involves the participation of two intact but unexpressed copies of mating-type information at the heterochromatic loci, HML alpha and HMRa, which are located at opposite ends of the same chromosome-encoding MAT. The study of MAT switching has yielded important insights into the control of cell lineage, the silencing of gene expression, the formation of heterochromatin, and the regulation of accessibility of the donor sequences. Real-time analysis of MAT switching has provided the most detailed description of the molecular events that occur during the homologous recombinational repair of a programmed double-strand chromosome break.