Flenniken A M, Newrock K M
Department of Biology, McGill University, Montreal, Quebec, Canada.
Dev Biol. 1987 Dec;124(2):457-68. doi: 10.1016/0012-1606(87)90499-4.
Histone H1 subtype complexity and H1 histone subtype synthesis switches were characterized during the development of normal embryos of the mud snail Ilyanassa obsoleta. The effect of the removal of the third polar lobe on the normal H1 pattern of synthesis was then investigated in the delobed embryo to determine if classical polar lobe effects are accompanied by a perturbation of these patterns. SDS-gel electrophoresis and fluorography of radiolabeled 5% perchloric acid-soluble nuclear extracts resolved six H1 proteins designated bands 1-6. Bands 1-5 migrate as a cluster of individual bands with similar mobilities. Band 6 has a substantially slower mobility. The synthesis of band 6 is predominant during the first 6 hr post-trefoil. During cleavage and gastrulation bands 1 and 2 are predominant while band 3, 4, and 5 become predominant during organogenesis. In addition, it has been found that removal of the polar lobe delays the off-switch of the early bands 6, 1, and 2 and the on-switch of the late bands 3, 4, and 5. This must result in a different H1 composition in the chromatin of the two embryo types. Cell number data of normal and delobed embryos reveal that the delay in subtype synthesis switching is not caused by an overall delay of cell division in the delobed embryo. However, the data indicate that a subpopulation of cells may not divide, or may divide late, in the delayed embryo. The data also suggest that the D cell lineage may be involved in the control of histone synthesis switching in the A, B, and C cell lineages.
在泥螺（Ilyanassa obsoleta）正常胚胎发育过程中，对组蛋白H1亚型复杂性和H1组蛋白亚型合成转换进行了表征。然后，在去除第三极叶的胚胎中研究了去除第三极叶对正常H1合成模式的影响，以确定经典的极叶效应是否伴随着这些模式的扰动。对放射性标记的5% 高氯酸可溶性核提取物进行SDS凝胶电泳和荧光显影，分离出六种H1蛋白，分别命名为条带1-6。条带1-5以具有相似迁移率的单个条带簇的形式迁移。条带6的迁移率明显较慢。条带6的合成在三叶期后最初6小时内占主导地位。在卵裂和原肠胚形成期间，条带1和2占主导地位，而在器官发生期间条带3、4和5占主导地位。此外，还发现去除极叶会延迟早期条带6、1和2的关闭转换以及晚期条带3、4和5的开启转换。这必然导致两种胚胎类型的染色质中H1组成不同。正常和去除极叶的胚胎的细胞数量数据表明，亚型合成转换的延迟不是由去除极叶的胚胎中细胞分裂的整体延迟引起的。然而，数据表明，在延迟的胚胎中，可能有一群细胞不分裂，或者分裂较晚。数据还表明，D细胞谱系可能参与了A、B和C细胞谱系中组蛋白合成转换的控制。
