The oligodendrocyte-myelin glycoprotein of mouse: primary structure and gene structure

The oligodendrocyte-myelin glycoprotein (OMgp), a phosphatidylinositol-linked membrane glycoprotein expressed in the brain, is in man encoded by a gene that is entirely within an intron of and on the strand opposite to the neurofibromatosis type 1 (NF1) gene. We obtained two distinct overlapping DNA clones from a mouse genomic library that contain the OMgp gene from mouse (mOMgp). There is a single intron in the 5' untranslated region in exactly the same position as the sole intron in the gene for the human OMgp (hOMgp). A repeat, (TC)24, in the mouse intron divides it into 5' and 3' segments that have 72 and 93% sequence identity, respectively, with the human gene. The deduced unprocessed polypeptides of both species have 440 amino acids and the similarity of the primary structures of mOMgp and hOMgp indicates conservation of function. The conservation of the nucleotide sequences of the coding, noncoding, and flanking regions of the two genes is remarkable and raises the possibility that the nucleotide sequence may serve a function that is separate from the role of encoding OMgp.