Generation of CNR1 Knockout Zebrafish Line and Assessment of Their Breeding Competency

The endocannabinoid system is a signaling system which consists of cannabinoid receptors, endogenous ligands, and metabolic enzymes. Impairing the system has deleterious effects in fertility, but the mechanisms underlying these effects are unknown. The objective of our study was to develop a cannabinoid receptor 1 (CNR1) knockout line of zebrafish (Danio rerio) and investigate the function of CNR1 in breeding competency. It was hypothesized that there will be a decrease in CNR1 mutant fertility and fecundity. We also generated a cnr1 knockout line via CRISPR-Cas9 and compared the breeding competency of cnr1+/- females with wild-type females, and there was no significant difference. Moving forward, we will assess the breeding competency of cnr1-/- females, as our results were inconclusive. Overall, we were able to successfully generate a cnr1 knockout line using CRISPR-Cas9. I anticipate that future research will provide a novel dataset to understand the involvement of this system in zebrafish reproduction.