Cell-specific accumulation of Drosophila proteasomes (MCP) during early development.

The proteasome (MCP) is a high relative molecular mass multicatalytic proteinase complex composed of nonidentical protein subunits. We have investigated the cellular distribution of the enzyme complex during Drosophila embryogenesis using the proteasome specific antibodies N19-35 and N19-28 for immunocytology. Antibody staining of whole-mount embryos shows that during embryogenesis proteasomes are present in proliferating cells and that their accumulation and turnover is differentially regulated. Our data suggest that the proteasome may serve different proteolytic processes and that the enzyme may be involved in cell-specific proteolytic events required for cell proliferation and morphogenesis during early Drosophila development.