Maturation-promoting factor during oocyte maturation of the catfish, <i>Heteropneustes fossilis </i>and the carp, <i>Labeo rohita</i>

Abstract

Cytosolic extract (CE) from mature oocytes of the catfish (<i>H. fossilis</i>) and carp (<i>L. rohita</i>)<i> </i>induces 100% germinal vesicle breakdown when microinjected into <i>Clarias </i>immature unstimulated oocytes. For the purpose of micro injection in fish oocytes a dose of ~ 50 nl is suggested as the optimum dose. SDS-PAGE analysis of CE prepared from immature and 17α, 20β-DP-induced mature oocyte showed some prominent and faint protein bands in the region of 34, 46 and 48 kDa. Two bands, at 32 and 34 kDa were detected in immature as well as mature oocytes by immunoblotting of SDS-PAGE with anti-PSTAIR antibody. Anti-cyclin B1 and B2 antibodies recognized 46 and 48 kDa proteins of mature oocytes, respectively. Anti-cyclin A antibody did not recognize any proteins of immature or mature oocytes. These findings indicate that catfish and carp MPF contain p34^cdc2 homologs and cyclin B molecules.