Oocytes and early embryos of Xenopus laevis contain intermediate filaments which react with anti-mammalian vimentin antibodies.

Previous studies have shown that Xenopus oocytes possess a cortical shell, which includes actin-containing microfilaments and cytokeratin-containing intermediate filaments. In this paper we show that oocytes of Xenopus laevis also contain filaments throughout their cytoplasm which are stained by several anti-vimentin antibody preparations. We also show that dramatic changes in pattern of these filaments occur during oocyte differentiation, first during vitellogenesis, and then during maturation of the oocyte to form an egg.