DISTRIBUTION OF PROSOME PROTEINS AND THEIR RELATIONSHIP WITH THE CYTOSKELETON IN OOGENESIS OF XENOPUS-LAEVIS

The presence of prosome proteins (p25K and p27K) was shown and their d istribution was studied in oogenesis of Xenopus laevis using immunoblo tting and immunofluorescence. These proteins form numerous granular cl usters of variable size all over the cell. At previtellogenic stages, the prosome antibodies homogeneously stain the oocyte nucleus and the evenly distributed relatively large clusters in the cytoplasm. As the oocyte grows, the pattern of distribution of the prosome proteins unde rgoes changes: animal-vegetal and cortical gradients appear in the cyt oplasm. In the course of oocyte maturation the size of clusters dimini shes. Artificial activation of the egg leads to a dorso-ventral gradie nt in distribution of the prosome proteins. In this way, specific loca lization of prosome proteins is first visualized during formation of t he dorso-ventral polarity. Co-localization of prosome proteins and act in and myosin was found in the oocyte by double staining. Small cluste rs of prosomes dispersed in the cytoplasm acquire capability of moveme nt (after artificial activation) due, in all likelihood, to persisting connection with the acto-myosin complex of the egg. (C) 1994 Wiley-Li ss, Inc.