[Histone synthesis in the cells of proliferating and nonproliferating tissues during gametogenesis and early...

A review of available data on the replication-dependent and replication-independent histone synthesis in the proliferating and nonproliferating (quiescent) cells during gametogenesis and early embryogenesis. In each of the considered models the replication-dependent and replication-independent histone synthesis play different roles in the chromatin organization and metabolism. The transition from replication-dependent to replication-independent histone synthesis during gametogenesis is a regular process directed to the formation of a highly compacted metabolically inert chromatin (males) and to the formation of histone protein pool in order to provide the chromatin nucleosome structure in the sperm nucleus during fertilization, as well as the nuclear chromatin in zygotes and blastomeres (females). A suggestion is put forward that the coupling of histone and DNA syntheses should arise not simultaneously in all cells of the embryo but have a regional pattern, due, possibly, to the asynchrony of cell cycle in the early embryos.