Two-dimensional electrophoretic analysis of proteins synthesized during the early cleavage period in rabbit embryos

Abstract

Changes in the pattern of polypeptide synthesis in early cleavage stages of rabbit embryos cultured in the presence and absence of the transcriptional inhibitor, α-amanitin, were studied by twodimensional polyacrylamide gel electrophoresis. Three categories of polypeptides were delineated: ( a) those which appear between the 2-cell and 16-cell stage in control embryos but whose appearance is inhibited by α-amanitin; ( b) those which are continuously produced and are resistant to α-amanitin transcriptional suppression; and ( c) those which are produced at the 2-cell and 16-cell stage in the absence of α-amanitin but are not produced when α-amanitin is present. The results suggest that protein synthesis in the 16-cell rabbit embryo is dependent upon both stable messenger RNA (mRNA) molecules preserved from before the 2-cell stage and other mRNA molecules transcribed from the zygote genome of the 2-cell and later embryo.