Knockdown of the cAMP-dependent protein kinase (PKA) Type Ialpha regulatory subunit in mouse oocytes disrupts meiotic arrest and results in meiotic spindle defects.
In mammalian oocytes, cyclic AMP-dependent protein kinase (PKA) is responsible for maintaining meiotic arrest. We examined the role of the predominant regulatory subunit, RIalpha in regulating PKA activity during mouse oocyte maturation by knocking down the protein levels using an RNA interference approach. In oocytes in which RIalpha protein was reduced to non-detectable levels, compensatory decreases were also observed in the RIIalpha and catalytic (Calpha) subunit levels. These oocytes resumed meiosis, despite culture under conditions that maintain elevated intracellular cAMP levels, suggesting that the remaining Calpha was not sufficient to maintain meiotic arrest. The resulting eggs, however, displayed meiotic spindle abnormalities and abnormal cleavage planes leading to extrusion of large polar bodies. These results demonstrate that RIalpha is required for regulating PKA activity in maturing oocytes and that compensatory upregulation of RII does not occur. Furthermore, we implicate PKA as a modulator of spindle morphology and function during meiosis.
Duncan
Francesca E
FE
Center for Research on Reproduction and Women's Health, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Moss
Stuart B
SB
Williams
Carmen J
CJ
D000818:Animals; D054756:Cyclic AMP-Dependent Protein Kinase RIalpha Subunit; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D005260:Female; D008540:Meiosis / Q000187:drug effects / Q000235:genetics; D051379:Mice; D009865:Oocytes / Q000166:cytology* / Q000201:enzymology; D012330:RNA, Double-Stranded / Q000235:genetics / Q000494:pharmacology; D008941:Spindle Apparatus / Q000187:drug effects / Q000201:enzymology / Q000648:ultrastructure*
D054756:Cyclic AMP-Dependent Protein Kinase RIalpha Subunit; C517835:Prkar1a protein, mouse; D012330:RNA, Double-Stranded; D017868:Cyclic AMP-Dependent Protein Kinases