The RAD6 protein of Saccharomyces cerevisiae polyubiquitinates histones, and its acidic domain mediates this activity.
The RAD6 protein of Saccharomyces cerevisiae polyubiquitinates histones, and its acidic domain mediates this activity.
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DOI：
10.1101/gad.2.11.1476
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发表时间：
1988-11
影响因子：
10.5
通讯作者：
Patrick Sung;S. Prakash;L. Prakash
中科院分区：
文献类型：
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作者：
Patrick Sung;S. Prakash;L. Prakash
酿酒酵母的RAD6基因是复制后修复紫外线损伤的DNA、DNA损伤诱导的诱变和孢子形成所必需的。在这里，我们证明了由RAD6基因编码的蛋白质，以前被证明是一种泛素结合（E2）酶，有效地倍增泛素化组蛋白H2A和H2B，得到含有多达7个或更多分子的泛素的产品。我们还表明，高酸性的23个残基的RAD6羧基末端的尾部结构域，其中包含总共20个酸性残基，是必不可少的组蛋白聚泛素化活性。由于RAD 6多酸尾是孢子形成功能所必需的，而不是RAD 6的DNA修复和诱导诱变功能所必需的，因此本观察结果表明，RAD 6蛋白的组蛋白多泛素化活性对于孢子形成是必需的，而不是DNA修复和诱导诱变。通过RAD6蛋白将多个泛素分子附着到组蛋白上可以通过泛素依赖性蛋白水解系统靶向降解组蛋白或改变染色质结构。本文所述的用于合成聚泛素化组蛋白的体外系统提供了研究这些可能性的手段。
The RAD6 gene of the yeast Saccharomyces cerevisiae is required for post-replication repair of UV-damaged DNA, DNA damage-induced mutagenesis, and sporulation. Here we demonstrate that the protein encoded by the RAD6 gene, previously shown to be a ubiquitin-conjugating (E2) enzyme, multiply ubiquitinates histones H2A and H2B efficiently to give products containing as many as seven or more molecules of ubiquitin. We also show that the highly acidic 23-residue RAD6 carboxy-terminal tail domain, which contains a total of 20 acidic residues, is essential for the histone-polyubiquitinating activity. Because the RAD6 polyacidic tail is required for the sporulation function but not for the DNA repair and induced mutagenesis functions of RAD6, the present observations suggest that the histone-polyubiquitinating activity of RAD6 protein is essential for sporulation but not for DNA repair and induced mutagenesis. Attachment of multiple molecules of ubiquitin to histones by RAD6 protein may serve to target the histones for degradation via the ubiquitin-dependent proteolytic system or to alter chromatin structure. The in vitro system for synthesizing polyubiquitinated histones described herein provides a means for investigating these possibilities.