IMMUNOCYTOCHEMICAL DETECTION OF CA2-DEPENDENT SUBSPECIES OF PROTEIN-KINASE-C IN MOUSE EMBRYOS BEFORE AND DURING COMPACTION()

To confirm the possibility that protein kinase C is involved in compac tion of mouse embryos, the presence and distribution pattern of Ca2+-d ependent subspecies of this enzyme in mouse embryos, before and during compaction, were examined immunocytochemically with three different m onoclonal antibodies. These were MC-1a, MC-2a and MC-3a, which selecti vely interact with the subspecies of the enzyme known as types I, II a nd III, respectively. Only when embryos were incubated with MC-3a, was immunofluorescence clearly detected in all cells of embryos before an d during compaction. This result demonstrates the presence of type III protein kinase C in embryos before and during compaction and suggests the possibility that the type III enzyme may be involved in compactio n. No marked differences were found in the distribution pattern of the type III enzyme between embryos examined before and during compaction .