LIPOPHORIN AND VITELOGENIN RECEPTORS IN THE REGULATION OF OOGENESIS AND FOLLICULAR ATRESIA IN DIPETALOGASTER MAXIMA, A VECTOR OF CHAGAS´ DISEASE.

LEYRIA JIMENA; RAMOS, FABIÁN O.; CANAVOSO LILIÁN

La Falda, Córdoba

Jornada; XXI Jornada Científica Sociedad de Biología de Córdoba; 2018

Sociedad de Biología de Córdoba

Vitellogenesis is a central event in the reproduction of the insects. It is regulated by nutritional and endocrine factors, including the juvenile hormone (JH). During vitellogenesis, vitellogenin (Vg) and lipophorin (Lp) are synthesized in the fat body, secreted into the hemolymph and further internalized by the oocytes throughout the endocytic receptors RVg and RLp, respectively. However, under deficient nutritional conditions, the ovarian tissue degenerate to an atretic stage and the oocytes are resorbed. In this work, we have studied the relevance of RVg, RLp and Met, the JH receptor, in the regulation of vitellogenesis and follicular atresia of Dipetalogaster maxima, a vector of Chagas´ disease. The experimental approaches included western blot and ELISA assays to quantify Vg and Lp in the hemolymph and RT-qPCR to evaluate the expression of the RVg, RLp and Met transcripts in ovarian tissue. Vg and Lp levels were significantly high at the beginning of the vitellogenic stage in comparison to those registered at pre-vitellogenesis and follicular atresia. This pattern correlated with the expression of RVg and RLp in the ovaries. Interestingly, the expression of Met in the ovarian tissue presented a similar profile to that of RVg and RLp, being up regulated at early vitellogenesis and significantly down regulated during follicular atresia. The results suggested that RVg and RLp, besides being molecular markers of the follicles to complete their development, participate in the process of atresia. In addition, our findings suggest for the first time that Met may be involved in the regulation of RVg and RLp expression during oogenesis.