SUBUNITS OF YEAST SWI & SNF COMPLEX ARE MEMBERS OF ACTIN RELATED PROTEIN

酵母SWI/SNF染色质重塑复合体由11个 紧密结合多肽(SWI1、SWI2、SWI3、SNF5、SNF6、SNF11、 SWP82、SWP73、SWP59、SWP61和SWP29)。我们已经使用了基质辅助 激光解吸电离飞行时间质谱仪 识别编码SWP59和SWP61亚基的基因。 令人惊讶的是，我们发现SWP59和SWP61是由ARP9和 ARP7基因分别编码与肌动蛋白相关的成员 蛋白质(ARP)家族。序列分析表明，ARP9和ARP7 与酵母肌动蛋白有24%-26%的相似性(48%-51%相似)，而且它们是 可能会维持肌动蛋白的整体折叠。删除以下任一项 ARP9或ARP7基因导致典型的Swi/Snf表型，包括生长 以半乳糖、甘油或蔗糖为底的介质上的缺陷 碳源。如果要表达一个 HO-LacZ融合基因及其对转录的完全增强作用 GAL4激活剂。两个ARP家族成员的身份鉴定为 SWI/SNF复合体的关键亚基表明该复合体可能 总共包含三个不同的ATPase亚基；此外， ARP7和ARP9与ATPase的HSP和HSC家族的相似性 提示SWI/SNF的染色质重塑可能 参与类似监护人的活动。C.L.Peterson，Y.赵，B.T.Chait 酵母SW1/SNF复合体的亚基是肌动蛋白的成员 相关蛋白(ARP)家族>《生物化学杂志》273，(1998)。

The yeast SWI/SNF chromatin remodeling complex is comprised of 11 tightly associated polypeptides (SWI1, SWI2, SWI3, SNF5, SNF6, SNF11, SWP82, SWP73, SWP59, SWP61, and SWP29). We have used matrix-assisted laser desorption ionization time-of-flight mass spectrometry to identify the genes that encode the SWP59 and SWP61 subunits. Surprisingly, we find that SWP59 and SWP61 are encoded by the ARP9 and ARP7 genes, respectively, which encode members of the actin-related protein (ARP) family. Sequence analyses have shown that ARP9 and ARP7 are 24-26% identical (48-51% similar) to yeast actin and that they are likely to maintain the overall actin fold. Deletion of either the ARP9 or ARP7 gene causes typical swi/snf phenotypes, including growth defects on media containing galactose, glycerol, or sucrose as sole carbon sources. ARP9 and ARP7 are also required for expression of an HO-lacZ fusion gene and for full transcriptional enhancement by the GAL4 activator. The identification of two ARP family members as crucial subunits of the SWI/SNF complex suggests that the complex may contain a total of three different ATPase subunits; furthermore, the similarity of ARP7 and ARP9 to the HSP and HSC family of ATPases suggests the possibility that chromatin remodeling by SWI/SNF may involve chaperone-like activities. C.L. Peterson, Y. Zhao, B.T. Chait "Subunits of the yeast SW1/SNF complex are Members of the Actin Related Protein (ARP) Family" J Biol Chem 273, (1998).