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

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).

Compartmentalization of DNA polymerases, alpha and gamma, in maturing oocytes of the loach (Misgurnus fossilis L.).

The nuclei (germinal vesicles - GV) were isolated from the maturing oocytes of the loach (Misgurnus fossilis L.) by means of microsurgery. The activities of DNA polymerases, alpha and gamma, in the extracts of GV and enucleated oocytes were determined by two techniques: from crude extracts and following ultracentrifugation of the extracts in glycerol gradients.

[RNA transport in the embryonic cell].

The modern data on RNA transport in the cells of early embryos are reviewed. A special attention is paid to the specificity of posttranscriptional mRNA transformation and the control of its transport from the nucleus to the cytoplasm. These processes in the embryonic cell differ from those in the adult one: in the embryos the rate of transport of mRNA molecules in the cytoplasm increases with the development (with the onset of gastrulation); the process of polyadenylation in some mRNA molecules takes place in the cytoplasm rather than in the nucleus; besides, the high molecular weight mRNA fractions are localized in the cytoplasm (in the adult cells they are found only in the nucleus).

[A radioautographic study of protein synthesis in loach blastoderm].

The dynamics of protein synthesis in the loach embryos has been studied by means of autoradiography at the stages of cleavage, blastula and gastrula. During the synchronous cleavage divisions, nuclear proteins are mainly synthesized. From the early blastula stage until the early gastrula stage, the intensity of nuclear protein synthesis increases 2.