Cairns B R, Levinson R S, Yamamoto K R, Kornberg R D
Department of Structural Biology, Stanford University School of Medicine, California 94305, USA.
Genes Dev. 1996 Sep 1;10(17):2131-44. doi: 10.1101/gad.10.17.2131.
Swi/Snf protein was purified previously from the yeast Saccharomyces cerevisiae as an 11-polypeptide complex, including five novel Swp polypeptides. Here we present evidence concerning the role of Swp73p in the function of the complex. Deletion mutants in the SWP73 gene display phenotypes similar to those of swi and snf mutants, and in addition are temperature-sensitive. Swp73p is required for transcriptional activation by full-length glucocorticoid receptor (GR), but not by all GR derivatives. Swp73p is also required for activation with an enhancer element that binds the transcription factors Swi5p and Pho2p, which may underlie the defects in HO expression observed with swi and snf mutants. A single amino acid change in the protein confers phenotypes that are similar to those observed in the swp73 delta strain, but in some cases the two strains behave differently. The extent to which Swp73p is required for assisting transcriptional activation depends on the activator and promoter tested. Homologs of SWP73 are present in S. cerevisiae, Ashbya gossypii, Caenorhabditis elegans, and mice, indicating that SWP73 may belong to a family of related genes encoding proteins with analogous functions.
Swi/Snf蛋白先前是从酿酒酵母中纯化出来的一种11多肽复合物，包括五种新的Swp多肽。在此我们提供有关Swp73p在该复合物功能中作用的证据。SWP73基因的缺失突变体表现出与swi和snf突变体相似的表型，此外还对温度敏感。全长糖皮质激素受体（GR）的转录激活需要Swp73p，但并非所有GR衍生物都需要。Swp73p对于与转录因子Swi5p和Pho2p结合的增强子元件的激活也是必需的，这可能是swi和snf突变体中观察到的HO表达缺陷的基础。该蛋白中的单个氨基酸变化赋予的表型与在swp73Δ菌株中观察到的相似，但在某些情况下这两种菌株的表现有所不同。辅助转录激活所需的Swp73p的程度取决于所测试的激活剂和启动子。SWP73的同源物存在于酿酒酵母、棉阿舒囊霉、秀丽隐杆线虫和小鼠中，表明SWP73可能属于一个相关基因家族，该家族编码具有类似功能的蛋白质。
