Rhythmic incorporation of P 32 and C 14 -uracil in early mitotic cycles of Limnaea (mollusc) eggs.

Abstract

Incorporation of P32 and C14-uracil into RNase-sensitive, acid-insoluble fraction takes place in well defined cycles in course of the early cleavage in Limnaea embryos. This suggests a cyclic RNA synthesis. 40-50% less RNA is transcribed during the latter half of each cell division cycle. The rhythm is absent in the homogenate. The relevance of the findings has been discussed.