Arylalkalamine N-acetyltransferase-1 functions on cuticle pigmentation in the yellow fever mosquito, Aedes aegypti.

Arylalkylamine N-acetyltransferase (aaNAT) catalyzes the acetylation of dopamine, 5-hydroxy-tryptamine, tryptamine, octopamine, norepinephrine and other arylalkylamines to form respective N-acetyl-arylalkylamines. Depending on the products formed, aaNATs are involved in a variety of physiological functions. In the yellow fever mosquito, Aedes aegypti, a number of aaNATs and aaNAT-like proteins have been reported. However, the primary function of each individual aaNAT is yet to be identified. In this study we investigated the function of Ae. aegypti aaNAT1 (Ae-aaNAT1) in cuticle pigmentation and development of morphology. Ae-aaNAT1 transcripts were detected at all stages of development with highest expressions after pupation and right before adult eclosion. Ae-aaNAT1 mutant mosquitoes generated using clustered regularly interspaced palindromic repeats (CRISPR) - CRISPR-associated protein 9 had no obvious effect on larval and pupal development. However, the mutant mosquitoes exhibited a roughened exoskeletal surface, darker cuticles, and color pattern changes suggesting that Ae-aaNAT1 plays a role in development of the morphology and pigmentation of Ae. aegypti adult cuticles. The mutant also showed less blood feeding efficiency and lower fecundity when compared with the wild-type. The mutation of Ae-aaNAT1 influenced expression of genes involved in cuticle formation. In summary, Ae-aaNAT1 mainly functions on cuticular pigmentation and also affects blood feeding efficiency and fecundity.