Study on the involvement of nuclear actin-related proteins in transcription, segregation, and damage repair of the genome

核肌动蛋白相关蛋白参与基因组转录、分离和损伤修复的研究

基本信息

批准号：
18580087
负责人：
HARATA Masahiko
金额：
$ 2.53万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2006
资助国家：
日本
起止时间：
2006 至 2007
项目状态：
已结题

项目摘要

The actin family consists of conventional actins and various actin-related proteins (Arps). The members of the actin family was evolved from the common ancestral molecule and share the basal structure. The function of actin has been studied extensively for a long time. On the other hand, since the identification of Arps was first reported rather recently (in 1992), Arps have not yet been fully characterized or analyzed. In Saccharomyces cerevisiae, some of chromatin remodeling and histone acetyltransferase complexes, and these nuclear Arps have multiple functions including the regulation of chromatin remodeling and histone acetyltransferase complexes. Nuclear Arps of vertebrates are also supposed to possess similar function; however, identification and analyses of nuclear Arps in vertebrates are just beginning. We indicated that a nuclear Arp of human, hArp5, was localized in the nucleus as well as yeast Arp5p and these two had evolutionarily conserved functions. We also found that hArp5 shuttled between the nucleus and the cytoplasm as well as actin. Importantly, hArp5 depletion by siRNA caused defect in the accumulation of phosphorylated H2AX (gamma-H2AX) in the process of DNA double-strand break (DSB) repair. Taken together with the observations that hArp5 stably associates with the hIno80 chromatin remodeling enzyme and is required for chromatin binding of hIno80, it is suggested that hArp5 has a regulatory role in DSB repair through the chromatin remodeling machinery of the INO80 complex. Recent yeast studies show that the yeast INO80 complex is required also for DNA replication processes. We also showed that anther human nuclear Arp, hArp8, was involved in chromosome segregation.

肌动蛋白家族由常规肌动蛋白和各种肌动蛋白相关蛋白（Arps）组成。肌动蛋白家族的成员是从共同祖先分子进化而来的，并且具有相同的基础结构。长期以来，肌动蛋白的功能已被广泛研究。另一方面，由于最近（1992 年）首次报道了 Arps 的鉴定，因此 Arps 尚未得到充分表征或分析。在酿酒酵母中，存在一些染色质重塑和组蛋白乙酰转移酶复合物，而这些核Arps具有多种功能，包括调节染色质重塑和组蛋白乙酰转移酶复合物。脊椎动物的核Arps也被认为具有类似的功能。然而，对脊椎动物核 Arps 的鉴定和分析才刚刚开始。我们指出，人类的核Arp hArp5 以及酵母Arp5p 都位于细胞核中，并且这两个蛋白具有进化上保守的功能。我们还发现hArp5以及肌动蛋白在细胞核和细胞质之间穿梭。重要的是，siRNA 造成的 hArp5 耗竭导致 DNA 双链断裂 (DSB) 修复过程中磷酸化 H2AX (gamma-H2AX) 积累缺陷。结合 hArp5 与 hIno80 染色质重塑酶稳定结合并且是 hIno80 染色质结合所必需的观察结果，表明 hArp5 通过 INO80 复合物的染色质重塑机制在 DSB 修复中具有调节作用。最近的酵母研究表明，酵母 INO80 复合物也是 DNA 复制过程所必需的。我们还表明，人类花药核 Arp hArp8 参与染色体分离。