The Expression Patterns of the Activin Receptors During Embryonic Gonadal
At early stages of development an embryo possesses bipotential gonads that can develop into a testis or an ovary. In mammals, sex determination is genetically controlled by the presence or absence of the Y chromosome, specifically the Sry gene (Sex-determining region of the Y chromosome). In mice, when the Sry gene expresses, testis differentiation starts at embryonic day 11.5 (E11.5). The differentiation of the testis eventually leads to inhibition of germ cell meiosis, which occurs in the female gonads. The inhibition of germ cell meiosis in the testis coincides with the testis-specific presence of activins and activation of their downstream signaling molecules, Smads. Activins activate the Smad 2/3 transcription factors by binding to the activin receptor, which is composed by activin receptors type I and type II. To understand the molecular mechanisms for the testis-specific activation of the Smad pathway, I plan to investigate which types of gonadal cells are expressing the activin receptors. Gonads from E13.5 and E14.5 CD1 mouse embryos were examined for the presence of the activin receptors using immunocytochemistry. Because Smad proteins are only detected in germ cells and some Sertoli cells in male gonads, I expect to detect expression of the activin receptors in germ cells and maybe Sertoli cells. Examination of the expression of the activin receptors in gonads will help us understand whether activins directly involve in inhibiting germ cell meiosis, which is the first critical step to establish two separate germ lines in sexual reproduction.
School:
University of Puerto Rico at Bayamón
Department:
Human Biology
Research Advisor:
Humphrey H-C Yao
Department of Research Advisor:
Veterinary Biosciences
Year of Publication:
2005