This study investigated the participation of MAPK in the resumption of meiosis [germinal vesicle breakdown (GVB)] in oocytes and cumulus expansion using oocyte-cumulus cell complexes (OCC) from @entity17222 -null @entity19 ( @entity17222 (tm1Ev)/ @entity17222 (tm1Ev), hereafter @entity17222 (-/-)). MAPK activity was not detected in @entity17222 (-/-) oocytes whether they matured in vivo or in vitro, with or without gonadotropin stimulation. Therefore, there are no pathways independent of @entity17222 that activate MAPK during gonadotropin-induced maturation. In contrast, MAPK activity was always detected coincident with GVB in @entity17222 (+/+) oocytes. Moreover, MAPK activity was detected in cumulus cells before gonadotropin-induced GVB in OCC regardless of genotype. A specific inhibitor ( @entity5732 ) of @entity13438 , a MAPKK required for MAPK activity, inhibited gonadotropin-induced GVB in OCC of both @entity17222 (+/+) and @entity17222 (-/-) @entity19 . Activation of MAPK was downstream of elevation of @entity268 . @entity5732 also inhibited cumulus expansion stimulated by FSH, epidermal growth factor, @entity5987 , and recombinant @entity32645 . It is concluded that under the in vitro conditions used here, gonadotropin-induced GVB requires the participation of MAPK activity in the cumulus cells, but not in the oocyte. Moreover, the induction of cumulus expansion also requires the participation of MAPK, and this action is downstream of both elevation of @entity268 and @entity32645 .

Mitogen-activated protein kinase activity in cumulus cells is essential for gonadotropin-induced oocyte meiotic resumption and cumulus expansion in the XXXX .

@entity268 :: ('CHEBI:17489', 'Chemical') :: ['cAMP'] @entity5732 :: ('MESH:C113580', 'Chemical') :: ['U0126'] @entity19 :: ('10090', 'Species') :: ['mice'] @entity13438 :: ('17242(Tax:10090)', 'Gene') :: ['MEK'] @entity17222 :: ('17451(Tax:10090)', 'Gene') :: ['Mos', 'MOS'] @entity5987 :: ('MESH:D015124', 'Chemical') :: ['8-bromo-cAMP'] @entity32645 :: ('14566(Tax:10090)', 'Gene') :: ['growth differentiation factor-9']
@entity19 :: (10090,Species) :: ['mouse']
