FUNCTIONAL CHARACTERIZATION OF gnb3b AND guk1b FOR PHOTORECEPTOR INTEGRITY IN A ZEBRAFISH MODEL FOR RETINITIS PIGMENTOSA

Abstract

RETINITIS PIGMENTOSA (RP) IS A DEBILITATING EYE DISEASE AFFECTING 1 IN 5000 PEOPLE. RP PATIENTS EXHIBIT ROD AND CONE PHOTORECEPTOR DEGENERATION WITH INTRA-RETINAL PIGMENT DEPOSITION THAT LEADS TO BLINDNESS. MUTATIONS IN THE UBIQUITOUSLY EXPRESSED PRE-MRNA SPLICING FACTORS, PRPF8/31, CAUSES RP BUT IT REMAINS UNCLEAR HOW THIS LEADS TO A RETINA-SPECIFIC PHENOTYPE. TRANSCRIPTOME ANALYSIS OF PRPF8/31 MORPHANT ZEBRAFISH RETINAS IDENTIFIED TWO NOVEL CANDIDATES, GNB3B AND GUK1B, WHICH WERE CHARACTERIZED BY GENE KNOCK-DOWN AND KNOCK-OUT IN ZEBRAFISH. GNB3B MORPHANTS AND MUTANTS HAVE ABERRANTLY FORMED CONE PHOTORECEPTORS, WHILE RODS ARE ONLY MILDLY AFFECTED. GUK1B MORPHANTS MIMICKED THE RP PHENOTYPE WITH ABSENT RODS AND PIGMENT DEPOSITION. CONTRARILY, IN GUK1B MUTANTS RODS APPEAR UNAFFECTED AND CONE PHOTORECEPTORS ARE MALFORMED, WITHOUT PIGMENT DEPOSITION. THIS SUGGESTS DIFFERENT PHENOTYPES IN MORPHANTS AND MUTANTS DEPENDING ON THE DEGREE OF GUK1B DOWN-REGULATION. IN CONCLUSION, GNB3B AND GUK1B