FUNCTIONAL CHARACTERIZATION OF THE ODORANT CO-RECEPTOR
FRANCO, T.A1.; OLIVEIRA, D.S1.; MOREIRA, M.F1.; LEAL, W.S2.; MELO A.C.A1.
1Universidade Federal do Rio de Janeiro, Instituto de Química, Departamento de Bioquímica; 2University of California-Davis.
Olfaction is part of the sensory modality that permits insects interpret the environment. Several proteins take part in this process, among which the most important is called the odorant co-receptor OrCo. The main goal of this study was characterized the olfactory co-receptor (OrCo) in Rhodnius prolixus, inferring on their biological functions by gene silencing. Using bioinformatics we found a single gene in the R. prolixus’s genome. This gene was named RproOrCo, has 7 introns and was located in the contig >R_prolixus-1.0_Cont0.234. RproOrCo codified a protein with 473 aa with 7 transmembrane domains that are characteristic of G protein coupled receptors (GPCRs). RproOrCo is expressed exclusively in antennae. qPCR analysis showed this is regulated by the blood meal. Fasting insects (21 days) have higher expression level when compared with fed insects. Male insects, regardless of nutritional status, have higher expression when compared with female insects. The RNAi technique was effective to silence the RproOrCo with reduction of approximately 73% in the gene expression. Interestingly the effect of gene silencing persisted for more than 100 days. The phenotypic effects of silencing involved: (1) lost of the ability to find vertebrate host, (2) the decrease of blood volume ingested, (3) increase in mortality rate, (4) the delay and decreased of molt rate, and (5) decrease of egg lay. The silencing of RproOrCo had no effect on mating, since all the groups tested have had to lay fertile eggs. Results from silencing insects were statistically significant at the 5% level. The results showed clearly that the odorant co-receptor is an excellent target for controlling of triatomine populations. Gene silencing by RNAi causes important physiological disturbs in the dynamics of find host, mortality, moulting and egg laying. Thus, the data present here open a new perspective for the control of vector-borne diseases.
Financial Support: FAPERJ, INCT-EM/CNPq, CAPES; Area: Biochemistry.
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