Strathern J, Shafer B, Hicks J, McGill C
Laboratory of Eukaryotic Gene Expression, National Cancer Institute-Frederick Cancer Research Facility, Maryland 21701.
Genetics. 1988 Sep;120(1):75-81. doi: 10.1093/genetics/120.1.75.
The product of the MAT alpha 2 gene is a DNA-binding protein that acts as a repressor of two different sets of cell type-specific genes. In alpha cells, the alpha 2 protein represses the transcription of several a-specific genes. In a/alpha cells, the alpha 2 protein acts together with the product of the MATa1 gene, the a1 protein, to repress several genes used by haploids in the mating process. In addition to the mat alpha 2 mutations that result in defects in both types of regulation, other mat alpha 2 alleles have been described that result in defects in the repression of a-specific genes but that do not affect the ability of the alpha 2 and a1 proteins to interact to repress the haploid-specific genes. We report here the isolation of a new class of mat alpha 2 mutations that do not affect the ability of the alpha 2 protein to repress a-specific genes, but that interfere with the ability of the alpha 2 protein to interact with the a1 protein to repress the haploid-specific genes and establish the a/alpha cell type. These mutations may help determine the means by which the a1 protein interacts with alpha 2 to expand the set of genes under its control.
MATα2基因的产物是一种DNA结合蛋白，它作为两种不同类型细胞特异性基因的阻遏物发挥作用。在α细胞中，α2蛋白抑制几种a特异性基因的转录。在a/α细胞中，α2蛋白与MATa1基因的产物a1蛋白共同作用，抑制单倍体细胞在交配过程中使用的几种基因。除了导致两种调控类型均出现缺陷的matα2突变外，还描述了其他matα2等位基因，这些等位基因导致a特异性基因的抑制存在缺陷，但不影响α2蛋白和a1蛋白相互作用以抑制单倍体特异性基因的能力。我们在此报告分离出一类新的matα2突变，这些突变不影响α2蛋白抑制a特异性基因的能力，但会干扰α2蛋白与a1蛋白相互作用以抑制单倍体特异性基因并建立a/α细胞类型的能力。这些突变可能有助于确定a1蛋白与α2相互作用以扩大其控制下基因集的方式。
