MOLECULAR REPRODUCTION AND DEVELOPMENT 64:96–105 (2003) Glycogen Synthase Kinase-3 Regulates Mouse

ABSTRACT Intracellular regulation of oocyte meiosis is not completely understood. However, reversible phosphorylation, which involves serine/ threonine protein kinases and phosphatases (PP), is an important mediator. Glycogen synthase kinase-3 (GSK-3) is a highly conserved serine/threonine protein kinase. Currently no reports exist on presence or func-tion of GSK-3 in mammalian oocytes. The aim of this study was to determine GSK-3 presence/absence, transcript and protein expression, intracellular protein distribution, and to investigate the functional impor-tance of GSK-3 in mouse oocyte meiosis. Germinal vesicle-intact (GVI) oocytes contained both GSK-3 transcript and protein. Although GSK-3 b-isoform is the only transcript identifiable in GVI oocytes, bot