BIOCHEMICAL AND MOLECULAR ASPECTS OF VITELLOGENIN, LIPOPHORIN AND THEIR PUTATIVE RECEPTORS IN OOCYTES OF Dipetalogaster maxima (HEMIPTERA: REDUVIIDAE)

QUINTANILLA MF; LEYRIA J; FRUTTERO LL; CANAVOSO LE

San Miguel de Tucumán

Otro; Tercera Reunión Conjunta de Sociedades de Biología de la República Argentina.; 2015

Sociedades de Biología de la República Argentina

Vitellogenesis is a central event in insect reproduction that elicits uptake and deposition of yolk protein precursors (YPP) and lipids in developing oocytes. At this stage, vitellogenin (Vg), the main YPP, and lipophorin (Lp), the main lipoprotein of insects, are taken up from the circulation by the oocytes through specific receptors. The aim of this work was to achieve a better understanding of the biochemical and molecular aspects of Vg, Lp and its putative receptors in the oocytes of Dipetalogaster maxima, a vector of Chagas disease. The metabolic pathways of Vg and Lp in vitellogenic oocytes were evaluated in vivo by injecting females with fluorescently labeled lipoproteins to follow the fate of the entire particle. The results indicated that Lp and Vg were endocytosed by vitellogenic oocytes, co-localizing in yolk bodies. The convergence of endocytic and non-endocytic pathways for Lp in the oocytes was also shown. A putative Vg receptor in the ovarian tissue that was up-regulated during vitellogenesis was identified by RT-qPCR. The B chain of ATP synthase (B-ATPase), recently reported as an Lp docking receptor in the midgut of the triatomine Pastrongylus megistus, was detected in enriched ovarian membrane preparations by western blot. Moreover, immunofluorescence assays allowed the detection of B-ATPase in the plasma membrane of oocytes and follicular cells. Taken together, our results indicated that in D. maxima, the putative Vg receptor and B-ATPase play a central role in regulating the storage of nutritional resources in the ovarian tissue during vitellogenesis.