The MUC9/OGP gene encodes the oviduct-specific secreted glycoprotein,
MUC9/OGP. This glycoprotein is a member of two protein superfamilies: the mucin
protein superfamily and the glycosyl hydrolase 18 one. It contains 11 exons and 10 introns.
Although MUC9/OGP genes cloned from different mammals display the same structure,
species-specific features have been observed for each gene. The mechanisms of
transcriptional regulation of the MUC9/OGP gene have been investigated. Comparative
studies of the cloned 5’-flanking promoter sequences showed that the homologous
MUC9/OGP genes demonstrate conservation of transcription factor-specific cis-elements,
but their individual promoters bear species-specific features that determine species-specific
expression of a given MUC9/OGP gene. The biosynthetic pathway leading to production of
the mature MUC9/OGP glycoprotein has been identified. Overt and covert functional
potentials of the MUC9/OGP mucin are discussed.
Keywords: MUC9/OGP, promoter, biosynthesis, domain structure, functions.
