Complete sequence and expression of a cDNA encoding a chicken 115-kDa melanosomal matrix protein.
A full-length cDNA clone encoding a 115-kDa melanosomal matrix protein (MMP115) was isolated from a cDNA library constructed from poly(A)+ RNA of the chicken pigmented epithelial cells. Sequence analysis showed that the cDNA encoded a polypeptide of 762 amino acids, including a hydrophobic signal peptide. There are no membrane-spanning regions, but there are five N-linked glycosylation signals. A cysteine- and histidine-rich domain is present near the C-terminus. A sequence of 24 amino acids is repeated three times in the polypeptide. A database search for homologies yielded no sequence similarities in other proteins. A plasmid containing the full-length cDNA was transferred into mouse cell lines by transfection. The transfected cells produced a protein that had the same size, 115 kDa, as the mature MMP115. When B16 mouse melanoma cells were transfected, the chicken MMP115 was expressed in the melanosomes. The presence of a specific sorting signal was suggested for localization of melanosomal proteins. Southern blot analysis has revealed that the homologues of the chicken MMP115 gene are found in many vertebrate genomes.
Department of Developmental Biology, National Institute for Basic Biology, Okazaki, Japan.
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Mochii
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Agata
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Eguchi
D000595:Amino Acid Sequence; D000818:Animals; D030161:Avian Proteins; D001483:Base Sequence; D002454:Cell Differentiation / Q000235:genetics; D002645:Chickens; D006801:Humans; D015151:Immunoblotting; D008544:Melanocytes / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010857:Pigment Epithelium of Eye / Q000166:cytology / Q000378:metabolism*; D010957:Plasmids; D011506:Proteins / Q000235:genetics* / Q000302:isolation & purification; D015183:Restriction Mapping; D012455:Salamandridae / Q000235:genetics; D014162:Transfection; D014981:Xenopus / Q000235:genetics
D030161:Avian Proteins; D011506:Proteins; C071193:MMP115 protein, Gallus gallus