Continuity of Protein Synthesis Through Cleavage Metaphase

Abstract

Protein synthesis continues without a decline in rate throughout the period of chromosome condensation and of cytokinesis in the first two cleavages of sea urchin embryos. The natural synchrony of the egg populations and the conditions of measurement allowed even a partial inhibition of synthesis to be observed. Our results do not explain the mechanism of inhibition of protein synthesis that occurs at metaphase in cultured mammalian cells, but it shows that such a change in rate is neither universal nor obligatory.