Molecular Characterization, Expression Analysis, and Physiological Roles of Allatotropin in Rhodnius prolixus

Rhodnius prolixus, the principal Chagas disease vector, requires a blood meal to complete its moult cycle into the next stage. Allatotropins (ATs), a family of peptides first isolated from Manduca sexta, have been shown to regulate the biosynthesis of juvenile hormone, an insect growth and development hormone; however, ATs, being multimodal peptides, also exhibit myotropic effects on some insect visceral muscles. Here, this AT family of peptides has been examined in R. prolixus. Genomic analysis revealed a cDNA fragment of 973bp encoding one mature amidated AT tridecapeptide (Rhopr-AT) with high transcript levels observed, via RTPCR, in the central nervous system (CNS) and pool of fat body and trachea. AT-like immunoreactive neurons were found throughout the CNS and AT-like immunoreactive processes were present on some peripheral tissues. Bioassays using hindgut and dorsal vessel contraction, however, failed to demonstrate any effect of Rhopr-AT on these tissues. Future work will examine the effects of Rhopr-AT on JH production.