Classes of proteins synthesized in oocytes, eggs, embryos, and differentiated tissues of Xenopus laevis.

Two-dimensional gel electrophoresis has been used to analyse protein synthesis in embryonic stages and in three differentiated tissues of Xenopus laevis. The patterns found in oocyte, unfertilized eggs, embryos shortly after fertilization and at progressively later stages of development have been characterized and compared with the patterns found in the brain, heart and liver of tadpoles. The results suggest that at least four classes of proteins can be recognized among the proteins synthesized, although other categories may exist. They also suggest that some proteins synthesized rapidly in the oocyte are likely to be synthesized in differentiated tissues as well, while proteins synthesized for the first time only after fertilization are much less likely to be synthesized in differentiated tissues.