Alternative titles; symbolsSMALL BREAST EPITHELIAL MUCIN; SBEMHGNC Approved Gene Symbol: MUCL1Cytogenetic location: 12q13.2 Genomic coordinates (GRCh38): 12:...
Alternative titles; symbols
HGNC Approved Gene Symbol: MUCL1
Cytogenetic location: 12q13.2 Genomic coordinates (GRCh38): 12:54,854,515-54,858,386 (from NCBI)
▼ Cloning and Expression
Using expression profiling of EST and SAGE databases, Miksicek et al. (2002) identified SBEM, which encodes a putative 90-amino acid protein. SBEM has a hydrophobic signal peptide, suggesting that it is a secreted protein subject to proteolytic processing, and it is predicted to be O-glycosylated. SBEM contains 3 tandem copies of a neutral octapeptide core repeat, and its N- and C-terminal regions are charged and fairly polar. These features are similar to many sialomucins, although the protein lacks a transmembrane domain and is shorter than most other known epithelial mucins. RNA hybridization analysis showed SBEM expression in only adult mammary and salivary glands. RT-PCR analysis revealed SBEM expression in breast tumor cell lines, primary human mammary epithelial cells, and several breast epithelial cell lines. Northern blot analysis detected a 600-bp transcript differentially expressed in 10 breast tumor samples. RT-PCR analysis detected SBEM expression in 51 of 54 human breast tumors; however, no correlation was found between SBEM signal and tumor characteristics. In situ hybridization revealed SBEM mRNA in epithelial tumor cells but not in stromal or inflammatory cells in any of the breast tumor sections studied. SBEM expression correlated with mammaglobin-1 (605562) expression, and the SBEM/mammaglobin-1 ratio was significantly higher in lymph node-positive tumors. SBEM mRNA expression was strongly associated with histopathologic detection of lymph node metastases (14 of 14 cases), whereas SBEM was not found in lymph nodes without histologically detectable tumor cells.
By database analysis, Miksicek et al. (2002) mapped the SBEM gene to chromosome 12q13.2.