The c-mos proto-oncogene product is a key element in the cascade of events leading to meiotic maturation of vertebrate oocytes. The expression of c-mos mRNA during oocyte maturation is regulated at the translational level by cytoplasmic polyadenylation. Two U-rich cytoplasmic polyadenylation elements (CPEs) in the 3' untranslated region of mouse c-mos mRNA are required for this process. The goal of this project is to isolate the factor(s) that bind to the CPEs of mouse c-mos mRNA and to determine the mechanism by which they activate polyadenylation and translation.
The CPE-binding factor (CPEB) will be isolated using several innovative approaches. Next, the binding of CPEB to c-mos mRNA and its role in polyadenylation will be analyzed. The RNA-binding domain and the effector domain of CPEB will be mapped. To investigate the mechanism of CPEB action, proteins interacting with its effector domain will be isolated using the yeast two-hybrid system. These proteins are expected to be involved in any of three processes: polyadenylation, translation or the regulation of meiosis, and are likely to establish links between these events.