ZFIN ID: ZDB-PUB-190322-11
Larval but not adult xanthophore pigmentation in zebrafish requires GTP cyclohydrolase 2 (gch2) function
Lister, J.A.
Date: 2019
Source: Pigment cell & melanoma research   32(5): 724-727 (Journal)
Registered Authors: Lister, James A.
Keywords: GCH1, neural crest, pteridine, tetrahydrobiopterin
MeSH Terms:
  • Animals
  • Embryo, Nonmammalian/cytology
  • Embryo, Nonmammalian/metabolism*
  • GTP Cyclohydrolase/genetics
  • GTP Cyclohydrolase/metabolism*
  • Gene Expression Regulation, Developmental*
  • Larva/genetics
  • Larva/growth & development*
  • Larva/metabolism
  • Melanophores/metabolism*
  • Pigmentation
  • Zebrafish
  • Zebrafish Proteins/genetics
  • Zebrafish Proteins/metabolism*
PubMed: 30896066 Full text @ Pigment Cell Melanoma Res.
Although xanthophores are found widely among poikilothermic species, the developmental and biochemical pathways underlying differentiation of these pteridine- and carotenoid-containing cells remain murky. I have identified a recessive zebrafish mutant, camembert (cmm), which displays defective xanthophore pigmentation during embryonic and larval stages with cells appearing greyish rather than yellow, but as an adult appears to have normally pigmented xanthophores and wild-type stripe pattern. Examination of molecular markers reveals that xanthophores are present in typical numbers and position in cmm embryos; however, the localization of transcripts for the gene GTP cyclohydrolase 2 (gch2), encoding a critical protein in the pteridine biosynthetic pathway, is strikingly altered. RT-PCR analysis indicates that gch2 transcripts in mutant embryos skip an exon or retain the intron upstream, and that no correctly spliced mRNA is made. Sequencing of genomic DNA reveals that the skipped exon is intact, but the retained intron contains a deletion of approximately 180 basepairs, just upstream of the splice acceptor. Microinjection of a gch2 BAC clone rescues yellow pigmentation in camembert larvae, confirming that the pigmentation defect is due to mutation of gch2. This article is protected by copyright. All rights reserved.