BIO

Tyson is a senior graduating in the Summer of 2023 and plans to apply to medical school. After participating in UROP last spring, he enrolled in Directed Individual Study, joining the JFadool lab, to continue his research on zebrafish UV cone opsin.

Isolating Mutant Alleles of opn1sw1 in Zebrafish

Abstract

Zebrafish (Danio rerio) have become a popular model organism for genetic and anatomical studies of the visual system due to their short reproductive cycle, low maintenance, and highly conserved genetic and anatomical characteristics across vertebrates. For example, the gene which encodes the cone opsin protein opn1sw1 (short-wave sensitive 1) in zebrafish, which facilitates UV vision, is orthologous to the gene which encodes the protein for blue-sensitive vision in humans.
Zelinka et al (2018) used CRISPR/Cas-9 to target rho. The resulting mutations represent novel models of photoreceptor degeneration in zebrafish. How these mutations cause cell degeneration is unknown. The goal of this research is to use the same approach to generate novel mutations at the opn1sw1 locus which are similar to those in rho which cause degeneration and to establish models for cone degeneration in zebrafish.
CRISPR/Cas9 was used for gene targeting of the opn1sw1 locus. Guide RNAs and Cas-9 protein were obtained from IDT. Injected animals were reared to adults. Injected fish were mated and the resulting F1 fish were genotyped for mutant alleles. F1 offspring carrying novel alleles were outcrossed with wild-type fish revealing 4 distinct mutant alleles. F1 carrier fish with the same alleles were inbred to bring the allele to homozygosity. Our working hypothesis is that a homozygous mutant will display photoreceptor dysfunction or cell death. These novel phenotypes can be used as a model for future research into the effects of the mutations that cause photoreceptor degeneration.

Keywords: Genetic, vision, transgenic, opsin, neurobiology