Hyperphosphorylation of nucleoplasmin facilitates Xenopus sperm decondensation at fertilization
Hyperphosphorylation of nucleoplasmin facilitates Xenopus sperm decondensation at fertilization
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DOI：
10.1074/jbc.271.13.7253
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发表时间：
1996-03-29
影响因子：
4.8
通讯作者：
Laskey, RA
中科院分区：
文献类型：
--
作者：
Leno, GH;Mills, AD;Laskey, RA
以前的研究表明，核磷蛋白核质蛋白执行第一阶段的染色质去凝聚的非洲爪蟾精子受精。它结合并去除精子中的碱性蛋白质，用组蛋白代替它们。我们现在表明，这种活性依赖于大量的过度磷酸化的核质蛋白，发生时，卵母细胞成熟成卵子。卵提取物或纯化的高磷酸化卵核质蛋白使精子染色质去致密化，并使精子碱性蛋白移动，比卵母细胞提取物或低磷酸化卵核质蛋白快得多。此外，卵核质溶酶的去磷酸化减慢精子解凝聚，并阻止精子染色质中碱性蛋白的去除。我们的结论是，核质蛋白的过度磷酸化是用来调节染色质结构的快速变化，伴随着非洲爪蟾的早期发展。
Previous studies showed that the nuclear phosphoprotein nucleoplasmin performs the first stage of chromatin decondensation of Xenopus sperm at fertilization. It binds and removes sperm basic proteins replacing them with histones. We now show that this activity depends upon the massive hyperphosphorylation of nucleoplasmin that occurs when oocytes mature into eggs. Egg extracts or purified hyperphosphorylated egg nucleoplasmin decondense sperm chromatin and re move sperm basic proteins much faster than oocyte extracts or hypophosphorylated oocyte nucleoplasmin. Furthermore, dephosphorylation of egg nucleoplasmin slows sperm decondensation and prevents basic protein removal from sperm chromatin. We conclude that hyperphosphorylation of nucleoplasmin is used to modulate the rapid changes in chromatin structure that accompany early development in Xenopus.