[Show abstract][Hide abstract] ABSTRACT: p28, a 28kD protein from toad (Bufo bufo gargarizans) oocytes, was identified by using p13(suc1)-agarose affinity chromatography. Sequence homology analysis of the full-length cDNA of p28 (Gene Bank accession number: AF 314091) indicated that it encodes a protein containing 224 amino-acids with about 55% identities and more than 70% positives to human, rat or mouse UCH-L1, and contains homological functional domains of UCH family. Anti-p28 monoclonal antibody, on injecting into the oocytes, could inhibit the progesterone-induced resumption of meiotic division in a dose-dependent manner. The recombinant protein p28 showed similar SDS/PAGE behaviors to the native one, and promoted ubiquitin ethyl ester hydrolysis, a classical catalytic reaction for ubiquitin carboxyl terminal hydrolases (UCHs). The results in this paper reveal that a novel protein, p28, exists in the toad oocytes, is a UCH L1 homolog, was engaged in the process of progesterone-induced oocyte maturation possibly through an involvement in protein turnover and degradation.
Cell Research 10/2002; 12(3-4):199-206. · 10.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Full grown oocytes derived from Bufo Bufo gargarizans rearing at high temperature environment (24 °C), never underwent GVBD after progesterone treatment. No p34cdc2 H1 kinase activity was detected in the oocytes after progesterone stimulation or OA microinjection; Western blotting analysis showed that the level of p34cdc2 and p33 in the oocytes are significantly lower than those in the oocytes derived from the hibernating toads (below 10 °C). 35S-Met incorporation analysis showed that when the oocytes were incubated at 6 °C, synthesis of about thirty different polypeptides was promoted or induced, including p34cdc2 and some other p13sucl-binding proteins. All these results indicated that a low temperature environment is essential for the oocytes of Bufo Bufo gargarizans to express and store some cell cycle drivers and its regulators, and to gain the maturation competence. These results will also provide a new clue for explaining the molecular mechanisms why gametogenesis of some organisms depends on a relative low temperature and how to maintain the geographical distribution of some animals.
Cell Research 01/1996; 6(2):115-124. · 10.53 Impact Factor