Dimova D, Nackerdien Z, Furgeson S, Eguchi S, Osley M A
Program in Molecular Biology, Sloan Kettering Cancer Center, New York, New York 10021, USA.
Mol Cell. 1999 Jul;4(1):75-83. doi: 10.1016/s1097-2765(00)80189-6.
Genetic and biochemical studies indicate that the evolutionarily conserved Swi/Snf complex acts at a subset of genes to help transcriptional activators function on chromatin templates. The mechanism by which this complex is targeted to specific chromosomal loci remains unknown. We show that Swi/Snf is required for expression of the yeast histone HTA1-HTB1 locus because of the role of Hir1p and Hir2p corepressors in negatively regulating transcription. Snf5p, Snf2p/Swi2p, and Swi3p, three components of the yeast Swi/Snf complex, coimmunoprecipitate with each Hir protein, and Snf5p is maximally associated with the HTA1-HTB1 promoter when the Hir-based repression system is intact and the Swi/Snf complex is functional. The data support a role for the Hir repressors in the gene-specific targeting of Swi/Snf.
遗传学和生物化学研究表明，进化上保守的Swi/Snf复合物作用于一部分基因，以帮助转录激活因子在染色质模板上发挥功能。该复合物靶向特定染色体位点的机制仍然未知。我们发现，酵母组蛋白HTA1-HTB1基因座的表达需要Swi/Snf，这是因为Hir1p和Hir2p共抑制因子在负调控转录中发挥作用。酵母Swi/Snf复合物的三个组分Snf5p、Snf2p/Swi2p和Swi3p与每个Hir蛋白共免疫沉淀，当基于Hir的抑制系统完整且Swi/Snf复合物功能正常时，Snf5p与HTA1-HTB1启动子的结合最为紧密。这些数据支持Hir共抑制因子在Swi/Snf的基因特异性靶向中发挥作用。
