Generation of a transparent killifish line through multiplex CRISPR/Cas9-mediated gene inactivation

Body pigmentation is a major limitation for in vivo imaging and thus for the performance of longitudinal studies in biomedicine. A possibility to circumvent this obstacle is the employment of pigmentation mutants, which are used in fish species like zebrafish and medaka. To address the molecular basis of aging, the short-lived African killifish Nothobranchius furzeri has recently been established as a model organism. Despite its short lifespan, N. furzeri shows typical signs of mammalian aging including telomere shortening, accumulation of senescent cells and loss of regenerative capacity. Here, we report the generation of a transparent N. furzeri line by simultaneous inactivation of three key loci responsible for pigmentation. We demonstrate that this stable line, named klara, can serve as a tool for different in vivo applications including behavioral experiments addressing mate choice and the establishment of a senescence reporter by homology-directed repair-mediated integration of a fluorophore into the cdkn1a (p21) locus.