A fatty acid synthase gene ( FASN3 ) from the integument tissue of Rhodnius prolixus contributes to cuticle water loss regulation

MORICONI, D. E.; DULBECCO, A. B.; JUÁREZ, M. P.; CALDERÓN-FERNÁNDEZ, G. M.

INSECT MOLECULAR BIOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2019

0962-1075

Fatty acid synthase is a multifunctional enzyme involved in the formation of fatty acids.Despite the role of fatty acids in cell signalling and energy metabolism, and asprecursors to pheromones and hydrocarbons that waterproof the cuticle, the insectfatty acid synthases have been scarcely studied. Here we perform the molecularcharacterisation of three fatty acid synthase genes (RPRC000123, RPRC000269 andRPRC002909) in the Chagas disease vector, Rhodnius prolixus. Gene expressionscreening by RT-qPCR showed that RPRC000123 and RPRC002909 are expressedalmost exclusively in the integument tissue whilst RPRC000269 is mostly expressed inthe fat body and also in several body organs. Phylogenetic analysis, together with geneexpression results, showed that RPRC000269, RPRC002909 and RPRC000123 areorthologues of Drosophila melanogaster FASN1, FASN2 and FASN3 genes,respectively. After RNAi-mediated knockdown of RPRC000123, insects diedimmediately after moulting to the next developmental stage. However, mortality wasprevented by placing the insects under saturated humidity conditions, suggesting thatdehydration might play a role in insects? death. Lipid analyses in RPRC000123-silenced insects showed reduced amounts of integument fatty acids and methylbranched hydrocarbons, compared to controls.These data support an important role for FASN3 in the biosynthesis of the precursorsto hydrocarbons that waterproof the insect cuticle.