Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, Illinois, USA.
Nat Struct Mol Biol. 2013 Feb;20(2):222-9. doi: 10.1038/nsmb.2486. Epub 2013 Jan 20.
The ISWI family of ATP-dependent chromatin remodelers represses transcription by changing nucleosome positions. ISWI regulates nucleosome positioning by requiring a minimal length of extranucleosomal DNA for moving nucleosomes. ISW2 from Saccharomyces cerevisiae, a member of the ISWI family, has a conserved domain called SLIDE (SANT-like ISWI domain) that binds to extranucleosomal DNA ~19 base pairs from the edge of nucleosomes. Loss of SLIDE binding does not perturb binding of the ATPase domain or the initial movement of DNA inside of nucleosomes. Not only is extranucleosomal DNA required to help recruit ISW2, but also the interactions of the SLIDE domain with extranucleosomal DNA are functionally required to move nucleosomes.
ISWI 家族的 ATP 依赖型染色质重塑酶通过改变核小体位置来抑制转录。ISWI 通过要求移动核小体的核小体外 DNA 具有最小长度来调节核小体定位。酿酒酵母中的 ISWI 家族成员 ISW2 具有一个保守结构域，称为 SLIDE（SANT 样 ISWI 结构域），该结构域与核小体边缘约 19 个碱基对的核小体外 DNA 结合。SLIDE 结合的缺失不会干扰 ATP 酶结构域的结合或 DNA 在核小体内部的初始运动。不仅需要核小体外 DNA 来帮助募集 ISW2，而且 SLIDE 结构域与核小体外 DNA 的相互作用对于核小体的移动也是功能必需的。
