@entity1 oocyte activation by the synergistic action of discrete sperm head components: induction of XXXX transients and involvement of proteolysis.

@entity1 @entity1605 @entity19 @entity460 @entity563 @entity141 @entity2483 @entity3457
@entity3457 ( @entity3457 ) elicits activation sufficient for full development and originates from sperm head submembrane matrices. @entity3457 comprises discrete, @entity2483 (referred to here respectively as @entity3457 -I and -II) which are each necessary but not sufficient to activate oocytes. The @entity1605 , @entity3457 -I(m), becomes solubilized from the perinuclear matrix under reducing conditions (the @entity3457 transition) to generate @entity3457 -I(s). Although @entity460 transients likely play an important role in oocyte activation at fertilization, the question is open as to whether demembranated heads or @entity3457 -I(s) and/or @entity3457 -II can induce @entity460 transients. We now report that injection of demembranated sperm heads into @entity19 oocytes efficiently induced @entity141 oscillations. When injected independently, @entity3457 -I(s) and demembranated heads heated to 48 degrees C failed to generate @entity141 oscillations. However, co-injection of @entity3457 -I(s) and 48 degrees C-heated heads induced oscillations, mirroring their synergistic ability to activate oocytes. This suggests that @entity3457 -mediated activation proceeds via pathways resembling those at fertilization and provides the first direct evidence that multiple sperm components are required to induce @entity141 oscillations. We probed the @entity3457 -I(s) liberation at the center of this activation and show that in vitro it was sensitive to a profile of @entity563 protease inhibitors. These findings support a model in which @entity1 oocyte activation, including the induction of @entity460 transients, involves proteolytic processing of @entity3457 from sperm head submembrane compartments.
