Pigmentary function and evolution of tyrp1 gene duplicates in fish.
The function of the tyrosinase-related protein 1 (Tyrp1) has not yet been investigated in vertebrates basal to tetrapods. Teleost fishes have two duplicates of the tyrp1 gene. Here, we show that the teleost tyrp1 duplicates have distributed the ancestral gene expression in the retinal pigment epithelium (RPE) and melanophores in a species-specific manner. In medaka embryos, tyrp1a expression is found in the RPE and in melanophores while tyrp1b is only expressed in melanophores. In zebrafish embryos, expression of tyrp1 paralogs overlaps in the RPE and in melanophores. Knockdown of each zebrafish tyrp1 duplicate alone does not show pigmentary defects, but simultaneous knockdown of both tyrp1 genes results in the formation of brown instead of black eumelanin accompanied by severe melanosome defects. Our study suggests that the brown melanosome color in Tyrp1-deficient vertebrates is an effect of altered eumelanin synthesis. Black eumelanin formation essentially relies on the presence of Tyrp1 and some of its function is most likely conserved from the common ancestor of bony vertebrates.
Braasch
Ingo
I
Physiological Chemistry I, University of Würzburg, Biozentrum, Am Hubland, Würzburg, Germany.
Liedtke
Daniel
D
Volff
Jean-Nicolas
JN
Schartl
Manfred
M
D000595:Amino Acid Sequence; D000818:Animals; D019143:Evolution, Molecular; D005091:Exons; D020440:Gene Duplication; D018507:Gene Expression Regulation, Developmental; D055785:Gene Knockdown Techniques; D006801:Humans; D007438:Introns; D008562:Membrane Glycoproteins / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D016376:Oligonucleotides, Antisense / Q000235:genetics / Q000378:metabolism; D009990:Oryzias / Q000235:genetics* / Q000378:metabolism; D010088:Oxidoreductases / Q000235:genetics* / Q000378:metabolism; D010858:Pigmentation / Q000235:genetics*; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D015027:Zebrafish / Q000196:embryology / Q000235:genetics* / Q000378:metabolism; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism*
D008562:Membrane Glycoproteins; D016376:Oligonucleotides, Antisense; D029961:Zebrafish Proteins; D010088:Oxidoreductases; C547074:Tyrp1b protein, zebrafish