HISTONE PHOSPHORYLATION AND CHROMATIN STRUCTURE DURING MITOSIS IN CHINESE-HAMSTER CELLS
HISTONE PHOSPHORYLATION AND CHROMATIN STRUCTURE DURING MITOSIS IN CHINESE-HAMSTER CELLS
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DOI：
10.1111/j.1432-1033.1978.tb12135.x
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发表时间：
1978-01-01
期刊：
影响因子：
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通讯作者：
TOBEY, RA
中科院分区：
文献类型：
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作者：
GURLEY, LR;DANNA, JA;TOBEY, RA
在同步化CHO中国仓鼠细胞中，在有丝分裂过程中检查组蛋白磷酸化和染色质结构。电镜观察细胞有丝分裂各期的细胞群体分布。进入有丝分裂发生在2个阶段：染色质聚集成致密的染色质团块在preprophase期间，然后通过这些聚集体的凝聚成染色体结构在前期。退出有丝分裂观察基本上是作为相反的过程，染色体首先被打乱成致密的染色质团块在末期，然后在早期G1这些聚集体的分散。将这些结构变化与组蛋白磷酸化相关联，发现在有丝分裂的间期和染色质聚集阶段（前前期和末期）存在涉及1-3个磷酸/分子的间期型组蛋白H1磷酸化（H11）。在细胞周期的这些时期没有发生组蛋白H3磷酸化。H11磷酸化可能与使用染色质结构的分子探针在间期观察到的染色质组织的亚显微变化有关。在有丝分裂过程中，组蛋白磷酸化与显微染色质结构变化相关。在有丝分裂的第二阶段（前期、中期和后期），当染色体结构完全浓缩时，几乎所有的组蛋白H1都以含有3-6个磷酸的超磷酸化分子（H1 M）存在，所有的组蛋白H3分子都被磷酸化。细胞从后期退出与H3去磷酸化为未磷酸化的H3和H1 M去磷酸化为含有0-3个磷酸的亚磷酸化H1密切相关。当这些细胞离开末期进入G1期时，亚磷酸化的H11进一步去磷酸化为未磷酸化的H1。H1 M超磷酸化和H3磷酸化是严格的有丝分裂事件，仅在染色体完全浓缩时发生。在这些实验中的一些中不存在秋水仙胺消除了H1 M和H3磷酸化是秋水仙胺处理的假象的可能性。组蛋白H1和H3可能对染色质结构施加限制，从而防止间期期间的染色体凝聚，并且H1 M和H3磷酸化在有丝分裂期间消除这种限制。
Histone phosphorylation and chromatin structure were examined in synchronized CHO Chinese hamster cells during progression through mitosis. Cell population distribution in various phases of mitosis was determined by EM. Entry into mitosis occurred in 2 stages: the gathering of chromatin into aggregates of dense chromatin clumps during preprophase, followed by the condensation of these aggregates into chromosome structures during prophase. Exit from mitosis was observed essentially as the reverse process, chromosomes first being disorganized into dense chromatin clumps during telophase, followed by dispersion of these aggregates in early G1. Correlating these structural changes with histone phosphorylation revealed that interphase-type histone H1 phosphorylation (H11) involving 1-3 phosphates/molecule existed in interphase and during the chromatin aggregation stages of mitosis (preprophase and telophase). No histone H3 phosphorylation occurred during these periods of the cell cycle. H11 phosphorylation may be involved with the submicroscopic changes in chromatin organization observed during interphase using molecular probes of chromatin structure. During mitosis, histone phosphorylation was correlated with microscopic chromatin structural changes. During the 2nd stage of mitosis (prophase, metaphase and anaphase), when chromosome structures were fully condensed, virtually all histone H1 existed as superphosphorylated molecules (H1M) containing 3-6 phosphates, and all histone H3 molecules were phosphorylated. Exit of cells from anaphase correlated closely with the dephosphorylation of H3 to unphosphorylated H3 and with the dephosphorylation of H1M to subphosphorylated H1 containing 0-3 phosphates. Further dephosphorylation of subphosphorylated H11 to unphosphorylated H1 occurred as these cells left telophase and entered G1. H1M superphosphorylation and H3 phosphorylation are strictly mitotic events which occur only when chromosomes are fully condensed. The absence of Colcemid in some of these experiments eliminates the possibility that H1M and H3 phosphorylations are artifacts of the Colcemid treatment. Histones H1 and H3 may impose a restriction on chromatin structure which prevents chromosome condensation during interphase, and the H1M and H3 phosphorylations remove this restriction during mitosis.