Cytoskeletal changes during oogenesis and early development of Xenopus laevis

The frog oocyte is well known for studies on the control of gene expression, but has been used much less in studies on the cytoskeleton. However, frog oocytes are very large single cells, whose cytoplasmic movements and asymmetries are fundamental to the correct development of the subsequent embryo. One particular example of asymmetrically distributed cytoplasm is germ plasm, thought to be important in the formation of the germ line. Data are presented that show that germ plasm is highly concentrated mass of cytoskeletal elements, which include tubulin, and an intermediate filament protein of molecular weight 55 X 10(3). The distribution of these molecules has been studied during oogenesis and during early post-fertilization development. The implications of these findings are discussed.