Identification of a fourth subunit of mammalian DNA polymerase δ
Identification of a fourth subunit of mammalian DNA polymerase δ
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DOI：
10.1074/jbc.m001217200
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发表时间：
2000-06-23
影响因子：
4.8
通讯作者：
Lee, MYWT
中科院分区：
文献类型：
--
作者：
Liu, L;Mo, JY;Lee, MYWT
用小牛胸腺DNA聚合酶δ（DNApolymerase delta）纯化小牛胸腺DNA，经常规层析分离得到一个12 kDa和两个25 kDa的多肽。从12 kDa的多肽中得到一个16-mer的多肽序列，该序列与人EST（AA 402118）的一个新的开放阅读框架相匹配，编码一种功能未知的假定蛋白。该蛋白被命名为p12。通过使用S.人EST AA 402118的开放阅读框编码107个氨基酸，预测分子量为12.4 kDa，与实验结果一致。p12与粟酒裂殖酵母Cdm 1的同源性为25%。这两个25 kDa的多肽序列都与假设的KIAA 0039蛋白质序列相匹配，该蛋白质序列最近被鉴定为pol δ的第三亚基。免疫亲和纯化的小牛胸腺pol δ的Western印迹显示p125、p50、p68（KIAA 0039产物）和p12的存在。这些研究为更详细地分析pol delta哺乳动物亚基的可能功能铺平了道路。
A 12-kDa and two 25-kDa polypeptides were isolated with highly purified calf thymus DNA polymerase delta by conventional chromatography, A 16-mer peptide sequence was obtained from the 12-kDa polypeptide which matched a new open reading frame from a human EST (AA402118) encoding a hypothetical protein of unknown function. The protein was designated as p12. Human EST AA402118 was identified as the putative human homologue of Schizosaccharomyces pombe Cdm1 by a tBlastn search of the EST data base using S. pombe Cdm1, The open reading frame of human EST AA402118 encoded a polypeptide of 107 amino acids with a predicted molecular mass of 12.4 kDa, consistent with the experimental findings. p12 is 25% identical to S pombe Cdm1. Both of the 25-kDa polypeptide sequences matched the hypothetical KIAA0039 protein sequence, recently identified as the third subunit of pol delta. Western blotting of immunoaffinity purified calf thymus pol delta revealed the presence of p125, p50, p68 (the KIAA0039 product), and p12, With the identification of p12 mammalian pol delta can now be shown to consist of four subunits. These studies pave the way for more detailed analysis of the possible functions of the mammalian subunits of pol delta.