RNA Pattern during Oogenesis and Early Embryogenesis

DNA-dependent RNA synthesis were still incompletely developed, although the localization of a considerable part of RNA synthesis in the nucleus and the morphogenetic role of the nucleus has been established, or particularly in experiments with transplantation of the nucleus under various experimental conditions. 

As soon as methods of identification and study of the forms of messenger RNA synthesized by the nucleus and controlling cytoplasmic syntheses in accordance with the nuclear genetic program were available, attempts were naturally made to study Neifakh s 

A series of important investigations in this direction was undertaken in Spirin s laboratory, in some cases with Neifakh s assistance (Belitsina et al., 1963a, b Aitkhozhin et al., 1964  

It was further shown that lethal irradiation (50,000 R) during the investigated intervals of early embryogenesis did not stop the synthesis of different forms of RNA and had no effect on the molecular characteristics of the isolated nucleic acids. However, DNA synthesis in the nuclei stopped almost completely soon after irradiation. Continuation of synthesis of mRNA after these high doses of irradiation did not mean, of course, that this synthesis 

The facts obtained by Neifakh concerning the action of radiation on development of the loach embryo clearly fit in much better with this explanation than with the original hypothesis of periodicity in morphogenetic activity of the nuclei. Neifakh himself has put forward a similar explanation of his early results (Neyfakh, 1964 Korolev and Neifakh, 1965). 

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