Condensation of DNA by spermatid basic nuclear proteins
Condensation of DNA by spermatid basic nuclear proteins
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DOI：
10.1074/jbc.m204755200
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发表时间：
2002-10-11
影响因子：
4.8
通讯作者：
Balhorn, R
中科院分区：
文献类型：
--
作者：
Brewer, L;Corzett, M;Balhorn, R
两个过渡蛋白，TP1和TP2，在哺乳动物精子发生的早期参与了精子细胞基因组的重新包装，与第一个可检测到的染色质凝聚变化一致。利用光学陷阱和双通道流动细胞将单个DNA分子移动到含有蛋白质的缓冲液中，我们测量了叙利亚仓鼠过渡蛋白TP1和TP2与蛋白P1和P2结合诱导的DNA凝聚和去凝聚速率。结果表明，这两种过渡蛋白浓缩游离DNA的速率与鱼精蛋白1和鱼精蛋白2相似。用TP1凝聚的DNA分子的稳定性明显低于用鱼精蛋白或TP2凝聚的DNA分子。用与TP2 c端25个残基对应的肽进行的实验表明，该结构域负责压缩DNA。用两个含有精氨酸和赖氨酸残基的TP1片段进行的实验表明，TP1的DNA结合必须涉及更多的基本序列。锌促进了P2对DNA的凝聚作用，但对TP2不起作用。DNA中TP2和P2的解离速率不受锌的影响。
Two transition proteins, TP1 and TP2, participate in the repackaging of the spermatid genome early in mammalian spermiogenesis, coincident with the first detectable changes in chromatin condensation. Using an optical trap and a two-channel flow cell to move single DNA molecules into buffer containing protein, we have measured the rates of DNA condensation and decondensation induced by the binding of Syrian hamster transition proteins TP1 and TP2 and protamines P1 and P2. The results show that both transition proteins condense free DNA, with rates similar to those of protamine 1 and 2. DNA molecules condensed with TP1 were significantly less stable than DNA condensed by protamine or by TP2. Experiments conducted with a peptide corresponding to the C-terminal 25 residues of TP2 showed that this domain is responsible for condensing DNA. Experiments conducted with two fragments of TP1 containing arginine and lysine residues demonstrated that DNA binding by TP1 must involve more than these basic sequences. Zinc facilitated the condensation of DNA by P2 but not by TP2. The dissociation rates of TP2 and P2 from DNA were not affected by the addition of zinc.