Functional disruption of Transferrin expression alters reproductive physiology in Anopheles culicifacies

Abstract

Iron metabolism is crucial to maintain optimal physiological homeostasis of every organism and any alteration of the iron concentration (i.e. deficit or excess) can have adverse consequences. Transferrins are glycoprotein’s that play important role in iron transportation and have been widely characterized in vertebrates, and insects, but poorly studied in blood-feeding mosquitoes. Here, we characterized a 2102 bp long transcript AcTrf1a encoding putative transferrin homolog protein from mosquito An. culicifacies . A detailed in silico analysis predicts AcTrf1a (ACUA023913-RA) encodes 624 amino acid (aa) long polypeptide that carries transferrin domain. AcTrf1a also showed a putative N-linked glycosylation site, a characteristic feature of most of the mammalian transferrin’s and certain non-blood feeding insects. Structure modelling prediction confers the presence of an iron binding site at the N-terminal lobe of the transferrin. Our spatial and temporal expression analysis under altered pathophysiological conditions showed that AcTrf1a abundantly express in the fat-body, ovary, and its response is significantly altered (enhanced) after blood meal uptake, and exogenous bacterial challenge. Additionally, a non-heme iron supplementation of FeCl 3 at 1 mM concentration not only augmented the AcTrf1a transcript expression in fat-body, also enhanced the reproductive fecundity of gravid adult female mosquitoes. RNAi mediated knockdown of AcTrf1a causes a significant reduction in the egg laying/fecundity, confirmed important role of transferrin in oocyte maturation . Further detailed characterization may help to select this transcript as a unique target to impair the mosquito reproductive outcome.