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oca2 regulation of chromatophore differentiation and number is cell type specific in zebrafish
Author(s) -
Beirl Alisha J.,
Linbo Tor H.,
Cobb Marea J.,
Cooper Cynthia D.
Publication year - 2014
Publication title -
pigment cell and melanoma research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.618
H-Index - 105
eISSN - 1755-148X
pISSN - 1755-1471
DOI - 10.1111/pcmr.12205
Subject(s) - chromatophore , zebrafish , biology , melanophore , melanosome , mutant , microbiology and biotechnology , mutation , genetics , albinism , gene , melanin
Summary We characterized a zebrafish mutant that displays defects in melanin synthesis and in the differentiation of melanophores and iridophores of the skin and retinal pigment epithelium. Positional cloning and candidate gene sequencing link this mutation to a 410‐kb region on chromosome 6, containing the oculocutaneous albinism 2 ( oca2 ) gene. Quantification of oca2 mutant melanophores shows a reduction in the number of differentiated melanophores compared with wildtype siblings. Consistent with the analysis of mouse O ca2‐deficient melanocytes, zebrafish mutant melanophores have immature melanosomes which are partially rescued following treatment with vacuolar‐type ATP ase inhibitor/cytoplasmic p H modifier, bafilomycin A 1. Melanophore‐specific gene expression is detected at the correct time and in anticipated locations. While oca2 zebrafish display unpigmented gaps on the head region of mutants 3 days post‐fertilization, melanoblast quantification indicates that oca2 mutants have the correct number of melanoblasts, suggesting a differentiation defect explains the reduced melanophore number. Unlike melanophores, which are reduced in number in oca2 mutants, differentiated iridophores are present at significantly higher numbers. These data suggest distinct mechanisms for oca2 in establishing differentiated chromatophore number in developing zebrafish.