A cytoplasmic factor promoting oocyte maturation: its extraction and preliminary characterization

Abstract

Cytoplasm of maturing amphibian oocytes possesses a factor that induces germinal vesicle breakdown. This factor was extracted from Rana pipiens eggs and assayed by microinjection in Xenopus laevis oocytes. The activity of this factor is Mg-dependent, Ca-sensitive, and associated with heat-labile protein. Centrifugation on a sucrose density gradient revealed that the factor exists in three different molecular sizes.