Passmore S, Elble R, Tye B K
Section of Biochemistry, Molecular and Cell Biology, Cornell University, Ithaca, New York 14853.
Genes Dev. 1989 Jul;3(7):921-35. doi: 10.1101/gad.3.7.921.
The Saccharomyces cerevisiae MCM1 gene product is a protein with multiple functions. It is a transcription factor necessary for expression of mating-type-specific genes and is also required for the maintenance of minichromosomes. MCM1 shows DNA-binding specificities similar to those of two previously reported DNA-binding factors, pheromone/receptor transcription factor (PRTF) and general regulator of mating type (GRM); like PRTF, its activity can be modulated by the alpha 1 protein. MCM1 binds to the dyad symmetry element 5'-CCTAATTAGG and related sequences, which we refer to as MCM1 control elements (MCEs). MCEs are found within the regulatory regions of a- and alpha-specific genes. Direct and indirect DNA binding assays suggest that a conserved 5'-ATTAGG in one-half of the dyad symmetry element is important for MCM1 binding whereas variants in the other half are tolerated. We have used a novel DNase I 'nicking interference' assay to investigate the interaction of MCM1 with its substrate. These data suggest that MCM1 binds as a dimer, interacting symmetrically with the ATTAGG residues in each half of the binding site. MCM1 contains striking homology to the DNA-binding domain of the human serum response factor (SRF) which mediates the transient transcriptional activation of growth-stimulated genes by binding to the serum response element (SRE). We have shown that MCM1 binds to the human c-fos SRE in vitro and, like other MCEs, the c-fos SRE exhibits MCM1-mediated upstream activating sequence (UAS) activity in vivo.
酿酒酵母MCM1基因产物是一种具有多种功能的蛋白质。它是交配型特异性基因表达所必需的转录因子，也是维持微型染色体所必需的。MCM1显示出与之前报道的两种DNA结合因子，即信息素/受体转录因子（PRTF）和交配型通用调节因子（GRM）相似的DNA结合特异性；与PRTF一样，其活性可被α1蛋白调节。MCM1与二元对称元件5'-CCTAATTAGG及相关序列结合，我们将其称为MCM1控制元件（MCE）。MCE存在于a特异性和α特异性基因的调控区域内。直接和间接DNA结合试验表明，二元对称元件一半中的保守5'-ATTAGG对MCM1结合很重要，而另一半中的变体则可被耐受。我们使用了一种新型的DNA酶I“切口干扰”试验来研究MCM1与其底物的相互作用。这些数据表明，MCM1以二聚体形式结合，与结合位点每一半中的ATTAGG残基对称相互作用。MCM1与人血清反应因子（SRF）的DNA结合结构域具有显著的同源性，SRF通过与血清反应元件（SRE）结合来介导生长刺激基因的瞬时转录激活。我们已经证明，MCM1在体外与人c-fos SRE结合，并且与其他MCE一样，c-fos SRE在体内表现出MCM1介导的上游激活序列（UAS）活性。
