Mouse silver mutation is caused by a single base insertion in the putative cytoplasmic domain of Pmel 17.
This laboratory has established in previous studies that Pmel 17, a gene expressed specifically in melanocytes, maps near the silver coat color locus (si/si) on mouse chromosome 10. In the current study, we have focused on determining whether or not the si allele carries a mutation in Pmel 17. Pmel 17 cDNA clones, isolated from wild-type and si/si murine melanocyte cDNA libraries, were sequenced and compared. A single nucleotide (A) insertion was found in the putative cytoplasmic tail of the si/si Pmel 17 cDNA clone. This insertion is predicted to alter the last 24 amino acids at the C-terminus. Also predicted is the extension of the Pmel 17 protein by 12 residues because a new termination signal created downstream from the wild-type reading frame. The mutation was confirmed by the sequence of the PCR-amplified genomic region flanking and including the mutation site. The fact that si/si Pmel 17 was not recognized by antibodies directed toward the C-terminal 15 amino acids of wild-type Pmel 17, indicated a defect in this region. We conclude from these results that silver pmel 17 protein has a major defect at the carboxyl terminus. The chromosomal location and the identification of a potentially pathologic mutation in si-Pmel 17 support our conclusion that Pmel 17 is encoded at the silver locus.
Kwon
B S
BS
Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis 46202.
Halaban
R
R
Ponnazhagan
S
S
Kim
K
K
Chintamaneni
C
C
Bennett
D
D
Pickard
R T
RT
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002478:Cells, Cultured; D017931:DNA Primers / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics; D007120:Immunochemistry; D008544:Melanocytes / Q000378:metabolism; D008562:Membrane Glycoproteins; D051379:Mice; D008969:Molecular Sequence Data; D009154:Mutation; D012150:Polymorphism, Restriction Fragment Length; D011506:Proteins / Q000235:genetics* / Q000276:immunology; D058951:gp100 Melanoma Antigen
D017931:DNA Primers; D018076:DNA, Complementary; D008562:Membrane Glycoproteins; C548642:Pmel protein, mouse; D011506:Proteins; D058951:gp100 Melanoma Antigen