Chapter 7 Cytokeratins in Oocytes and Preimplantation Embryos of the Mouse

Abstract

Publisher Summary It is believed that the formation of different types of intermediate filaments (IFs) is associated with cell differentiation and that once the expression of specific IF proteins has started, then it becomes a stable feature of a differentiated cell. Therefore, IF proteins, including specific combinations of keratin polypeptides, are now used increasingly as cell-type-specific markers in the studies on various differentiating systems. The analysis of IF proteins might yield information on cell lineages and special interest should be addressed to the composition of the IF cytoskeleton of germ cells and early embryonic cells. This chapter summarizes the current partially-controversial knowledge of the IF cytoskeleton of mouse oocytes and preimplantation embryos. It also reviews the expression of IF proteins in germ cells of other species and in germ cell-derived tumor cells—teratocarcinoma stem cells. In contrast with earlier views, IF proteins have now been identified in germ cells. Thus, human spermatozoa contain vimentin, Xenopus oocytes and early embryos show vimentin and cytokeratin filaments, and mouse oocytes and early embryos seem to contain cytokeratin.