Banerjee S, Smallwood A, Hultén M
LFS Research Unit, DNA Laboratory, Birmingham Heartlands Hospital, UK.
J Cell Sci. 1995 Feb;108 ( Pt 2):755-65. doi: 10.1242/jcs.108.2.755.
Chromosomes in terminally differentiated mammalian spermatozoa are extensively condensed by protamines but a small proportion of histones remain. We examined the primary organization of somatic-type chromatin in lysolecithin-permeabilized human sperm nuclei and report that nucleosomes are closely packed with a periodicity of approximately 150 bp. Incubation of nuclei in the presence of exogenous Mg2+ and ATP induced chromatin reorganization leading to an increase in spacing of the nucleosomes to approximately 190 bp. This ATP-dependent chromatin rearrangement involved phosphorylation of both protamine and histone H2a. Increase in linker length between nucleosomes correlated with the phosphorylation of H2aX, the major H2a variant in human spermatozoa, predominantly at the C-terminal end. Chromatin reorganization was independent of detectable nuclear dispersion, which is an early chromosomal event in male pronuclear formation during fertilization.
终末分化的哺乳动物精子中的染色体被鱼精蛋白广泛压缩，但仍保留一小部分组蛋白。我们研究了经溶血卵磷脂通透处理的人类精子核中体细胞型染色质的初级组织，并报告核小体紧密堆积，周期约为150 bp。在存在外源Mg2+和ATP的情况下孵育细胞核会诱导染色质重组，导致核小体间距增加至约190 bp。这种依赖ATP的染色质重排涉及鱼精蛋白和组蛋白H2a的磷酸化。核小体间连接长度的增加与H2aX（人类精子中主要的H2a变体）的磷酸化相关，主要发生在C末端。染色质重组与可检测到的核分散无关，核分散是受精过程中雄性原核形成过程中的早期染色体事件。
