Mutation of brain aromatase disrupts spawning behavior and reproductive health in female zebrafish

Aromatase (Cyp19a1) is the steroidogenic enzyme that converts androgens into bioactive estrogens, and hence is in a pivotal position to mediate reproduction and sexual behavior. In teleosts, there are two aromatase paralogs: that is highly expressed in granulosa and Leydig cells in the gonads with critical function in sexual differentiation of the ovary, and that is highly expressed in radial glial cells in the brain with unknown roles in reproduction. mutant zebrafish lines were used to investigate the importance of the paralogs for spawning behavior and offspring survival and early development. Mutation of was found to increase the latency to the first oviposition in females. Mutation of in females also increased the number of eggs spawned; however, significantly more progeny died during early development resulting in no net increase in female fecundity. This finding suggests a higher metabolic cost of reproduction in mutant females. In males, the combined mutation of both paralogs resulted in significantly lower progeny survival rates, indicating a critical function of during early larval development. These data establish the specific importance of for female spawning behavior and the importance of the paralogs for early larval survival.