Chua P, Roeder G S
Department of Biology, Yale University, New Haven, Connecticut 06520-8103, USA.
Mol Cell Biol. 1995 Jul;15(7):3685-96. doi: 10.1128/MCB.15.7.3685.
The BDF1 gene of Saccharomyces cerevisiae is required for sporulation. Under starvation conditions, most cells from the bdf1 null mutant fail to undergo one or both meiotic divisions, and there is an absolute defect in spore formation. The Bdf1 protein localizes to the nucleus throughout all stages of the mitotic and meiotic cell cycles. Analysis of spread meiotic nuclei reveals that the Bdf1 protein is localized fairly uniformly along chromosomes, except that it is excluded specifically from the nucleolus. A bdf1 null mutant displays a reduced rate of vegetative growth and sensitivity to a DNA-damaging agent. The BDF1 gene encodes a 77-kDa protein that contains two bromodomains, sequence motifs of unknown function. Separation-of-function alleles suggest that only one of the two bromodomains is required for sporulation, whereas both are required for Bdf1 function in vegetative cells. We propose that the Bdf1 protein is a component of chromatin and that the mitotic and meiotic defects of the bdf1 null mutant result from alterations in chromatin structure.
酿酒酵母的BDF1基因是孢子形成所必需的。在饥饿条件下，bdf1基因缺失突变体的大多数细胞无法进行一次或两次减数分裂，并且在孢子形成方面存在绝对缺陷。Bdf1蛋白在有丝分裂和减数分裂细胞周期的所有阶段都定位于细胞核。对展开的减数分裂细胞核的分析表明，Bdf1蛋白沿染色体相当均匀地定位，只是它被特异性地排除在核仁之外。bdf1基因缺失突变体表现出营养生长速率降低以及对DNA损伤剂敏感。BDF1基因编码一种77 kDa的蛋白质，该蛋白质包含两个溴结构域，其功能未知。功能分离等位基因表明，两个溴结构域中只有一个是孢子形成所必需的，而两个溴结构域对于营养细胞中的Bdf1功能都是必需的。我们提出Bdf1蛋白是染色质的一个组成部分，并且bdf1基因缺失突变体的有丝分裂和减数分裂缺陷是由染色质结构改变引起的。
