Iridophore Expression in Mutant oca2 Zebrafish (Danio Rerio)

WSU Vancouver Honors ThesisThe gene oculocutaneous albinism 2 (oca2) is crucial for the proper development of color pattern in fish, and eye, hair and skin color in humans. When this gene is mutated (not functioning) in humans, albinism occurs, which makes those affected by this disease more susceptible to skin cancers caused by ultraviolet beta induced damage to DNA. Within zebrafish (Dania rerio) there are three cells which produce pigment: brown/black melanophores, iridescent iridophores, and yellow xanthophores. When oca2 is mutated the zebrafish exhibit a decrease in the number of melanophores but an increased number of iridophores. This result suggests that the oca2 gene is involved in regulating iridophore production. The goal of this experiment was to determine the mechanism by which oca2 influences the production of iridophores. It was determined that oca2 is not involved in regulating the number of iridophores at initiation (cell fate choice). This result may suggest that this gene is rather involved in regulating a second means for controlling cell number by cell division. To address this question, cell division assays will be completed over the summer to determine how iridophore cell proliferation is impacted when oca2 is mutated. Further understanding the mechanisms by which this gene regulates pigmentation within zebrafish will grant a better understanding of the importance and function of this gene within humans