Embryonic gonads of hormonal sex determinated Caiman latirostris females differ from those of temperature sex determined exhibiting an unbalance between proliferation and apoptosis?

GALOPPO G; RAMOS JG; DURANDO M; MUÑOZ-DE-TORO M; CANESINI G; LUQUE EH

Buenos Aires

Jornada; XVIII Jornadas Anuales Multidisciplinarias de la Sociedad Argentina de Biología.; 2016

Sociedad Argentina de Biología

Ovarian development in Caiman latirostris embryos can be triggered by any of these two factors: temperature (TSD) and estrogenic action known as hormone-­ dependent sex determination (HSD).To obtain a healthy population of oocytes in the adulthood, during the female gonadal differentiation process, germinal cells exhibit proliferation, meiosis and apoptosis. In this context, a fine tuning of the proliferation/apoptosis balance is expected. In stage 22,24 and 27 of embryonic development (embryonic gonad differentiation period) of TSD and HSD females, we assessed by immunohistochemistry the expression of Proliferating Cell Nuclear Antigen (PCNA) and TAp63 isoform (p53 family member). In mammals, TAp63 participate in the oocyte DNA damage response check point, one of the early events in the apoptotic-­ mediated selection process. Regarding cellproliferation, we observed higher expression of PCNA in the stage 22 of the HSD group. Also, we detected specific TAp63 immunoreactivity in caiman embryos germ cells (previously identified by VASA), being higher in the gonads of HSD females in all embryonic stages. In our knowledge, this is the first report describing the expression of TAp63 during thegonad development of a reptile. Increased expression of TAp63 suggests increased DNA damage of germ cells in the gonad of HSD females thus increased germ cell apoptotic death could be expected. Proliferation/apoptosis unbalance could produce significant alterationsB of theovarian oocytes reserveBduring adulthood.