Mt. Bassi et al., CLONING OF THE MURINE HOMOLOG OF THE OCULAR ALBINISM TYPE-1 (OA1) GENE - SEQUENCE, GENOMIC STRUCTURE, AND EXPRESSION ANALYSIS IN PIGMENT-CELLS, PCR methods and applications, 6(9), 1996, pp. 880-885
We report the isolation of the mouse homolog of OA1, the gene responsi
ble for ocular albinism type 1. The mouse Oa1 gene encodes a putative
protein of 405 amino acids displaying a high level of homology (78% id
entity, 87% similarity) to the human gene. All disease-associated miss
ense mutations reported in patients with ocular albinism involve conse
rved amino acid residues in the mouse protein. Moreover, the murine ho
molog shows six putative transmembrane domains, as observed for the hu
man gene, indicating that the overall structure of the two proteins is
conserved. The genomic organization is also conserved between the two
species across the entire coding region with splice sites located in
the same positions. Like its human counterpart, the expression pattern
of Oa1, apart from the eye, is restricted to the epidermal melanocyte
lineage. A transcript of similar to 1.8 kb was readily detected by th
is probe in 5 out of 5 murine melanocyte lines, 4 out of 4 murine mela
noblast lines, 1 out of 2 murine melanoma lines, and 1 out of 2 human
melanoma lines tested, but it was not detected in 2 out of 2 lines of
a developmentally earlier normal cell type, melanoblast precursor cell
s, suggesting that the gene is transcriptionally activated in epiderma
l melanocytes at the same stage as most other tested melanosomal prote
ins. Together, these data suggest that the function of the OA1 gene is
conserved between human and mouse and point to the mouse as a model t
o facilitate the understanding of ocular albinism pathogenesis.