title: Tyrosinase localization in mollusc shells.
abstract: In molluscan shellfish, pigmentation is frequently observed in the calcified shell, but the molecular basis of this process is not understood. Here, we report two tyrosinase proteins (Pfty1 and Pfty2) found in the prismatic shell layer of the pearl oyster Pinctada fucata; this layer is recognized as the pigmented region in P. fucata. The protein sequences were deduced from the corresponding cDNAs and confirmed by MALDI-TOF/TOF analysis. The sequences suggest that both tyrosinases have two copper-binding sites in similar N-terminal domains that are homologous to tyrosinases of cephalopods and hemocyanins of gastropods. In turn, this suggests that bivalve tyrosinases are evolved from a common ancestral copper-binding protein in the mollusc. Pfty1 and Pfty2 were specifically expressed in the mantle, and their expression in the mantle is different from each other, suggesting that these tyrosinases have distinctive roles in melanogenesis in shells.
authors.affiliation: Wakayama Prefecture Collaboration of Regional Entities for the Advancement of Technological Excellence, Japan Science and Technology Agency, 60 Ogura, Wakayama-Shi, Wakayama, Japan.
authors.forename: Kouhei
authors.initials: K
authors.lastname: Nagai
authors.forename: Masato
authors.initials: M
authors.lastname: Yano
authors.forename: Koichi
authors.initials: K
authors.lastname: Morimoto
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Miyamoto
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D015152:Blotting, Northern; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D003300:Copper / Q000378:metabolism; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel; D020869:Gene Expression Profiling; D015971:Gene Expression Regulation, Enzymologic; D007527:Isoenzymes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D014442:Monophenol Monooxygenase / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D010802:Phylogeny; D049911:Pinctada / Q000201:enzymology / Q000235:genetics*; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D002352:Carrier Proteins; D018076:DNA, Complementary; D007527:Isoenzymes; C023548:copper-binding protein; D003300:Copper; D014442:Monophenol Monooxygenase