title: Biochemical and cytological changes associated with expression of deregulated pp60src in Xenopus oocytes.
abstract: We have examined the effects of Xenopus pp60c-src with constitutive kinase activity on the morphology and maturation of Xenopus laevis oocytes. When RNA encoding this deregulated variant was injected into stage VI oocytes, we observed a gross alteration in the cortex of the oocyte. This alteration involved aggregation of pigment and invagination of the cortex in a large area proximal to the site of injection. This phenomenon was not seen in oocytes injected with RNA encoding wild-type pp60c-src. We have correlated this phenomenon with the tyrosine phosphorylation of 84- and 100-kDa proteins. These phosphorylated proteins colocalized with the alteration in the oocyte cortex when assayed by both biochemical and immunocytochemical methods. Neither the pigment aggregation nor phosphorylation of the 84- and 100-kDa proteins was observed in oocytes expressing a nonmyristoylated version of the deregulated pp60c-src. Expression of deregulated Xenopus fyn, a src-family member, resulted in a phenotype similar to that seen with deregulated src. However, in the fyn-injected oocytes, many more proteins were phosphorylated on tyrosine than in the src-injected oocytes. Progesterone stimulation of oocytes expressing deregulated pp60c-src resulted in an increase in the number of tyrosine-phosphorylated proteins. This change may represent the response of pp60src to the resumption of the cell cycle in maturing oocytes. These data suggest that the oocyte may be a particularly useful system for investigating the role of pp60c-src in the regulation of cytoskeletal structure and in the regulation of events associated with the cell cycle.
mesh_terms: D016475:3T3 Cells; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D004247:DNA; D005455:Fluorescent Antibody Technique; D007700:Kinetics; D051379:Mice; D008845:Microinjections; D008969:Molecular Sequence Data; D009227:Myristic Acids / Q000378:metabolism; D009865:Oocytes / Q000166:cytology / Q000254:growth & development / Q000378:metabolism*; D010766:Phosphorylation; D011374:Progesterone / Q000494:pharmacology; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism; D051076:Proto-Oncogene Proteins c-fyn; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000235:genetics / Q000378:metabolism*; D014170:Transformation, Genetic; D014443:Tyrosine / Q000378:metabolism; D029867:Xenopus Proteins; D014982:Xenopus laevis
chemical_list: D009227:Myristic Acids; D011518:Proto-Oncogene Proteins; D029867:Xenopus Proteins; D014443:Tyrosine; D011374:Progesterone; D004247:DNA; C494963:Fyn protein, Xenopus; C494960:Fyn protein, mouse; D051076:Proto-Oncogene Proteins c-fyn; D016392:Proto-Oncogene Proteins pp60(c-src)