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酵母Sir2蛋白中的一种酶活性,对基因沉默至关重要

J C Tanny¹, G J Dowd, J Huang

¹Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA.

|January 5, 2000

概括

对转录沉默至关重要的Sir2蛋白质作为ADP-ribosyltransferase起作用. 这种对基因沉默至关重要的酶活性依赖于保存的胺残留物.

科学领域:

生物化学生物化学
分子生物学分子生物学
遗传学是一个遗传学.

背景情况:

Sir2蛋白在不同物种中保存,并且已知参与转录沉默.
尽管它很重要,但其精确的分子功能仍然难以捉摸.

研究的目的:

为了阐明Sir2蛋白的未知功能.
调查Sir2在转录沉默中的酶活性和体内作用.

主要方法:

在体外使用标记的尼古丁胺胺腺因二核酸 (NAD+) 的酶分析.
使用抗单一ADP-ribose抗体进行蛋白质修饰分析.
在Sir2中保存的西斯提丁残留物的位点定向突变发生.
野生型和突变的Sir2蛋白质的染色质关联研究.

主要成果:

在实验室中,Sir2被证明可以将酸盐从NAD+转移到自身和基因组.
Sir2表现出ADP-ribosyltransferase活性,自我修饰并形成一种由抗单抗ADP-ribose抗体识别的产物.
保存的西斯蒂丁残留物的突变取消了Sir2的酶活性和体内静音功能.
突变的Sir2蛋白与染色素和沉默因子保持了相关性.

结论:

Sir2具有一种重要的ADP-ribosyltransferase活性.
这种酶活性对于Sir2蛋白在转录基因沉默中的作用至关重要.
保存的伊斯蒂丁残留物对Sir2的酶功能和其在沉默中的生物作用至关重要.

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