Mucin 3B, Cell Surface Associated (MUC3B)

The MUC3A gene, originally designated MUC3, encodes a transmembrane mucin-type glycoprotein. A number of consistent single nucleotide changes were observed in different MUC3 cDNAs from a single individual, suggesting the presence of at least 3 different transcripts. this transcript heterogeneity is due to the existence of allelic changes and to tandem duplication of the MUC3 gene.that the second gene, which they designated MUC3B, has the same C-terminal domain and intron-exon structure as that previously described for MUC3. The tandem repeat domain has the same amino acid consensus sequence but shows more substitutions. RT-PCR detected expression of MUC3B in fetal and adult small intestine, fetal and adult colon, and Caco-2 cells.MUC3A and MUC3B, both of which encode membrane-bound mucins with 2 epidermal growth factor-like motifs and a putative transmembrane region.