Characterization of Human Mucin (MUC15) and Identification of Ovine and Caprine Orthologs

Immunodetection of mucin 15 (MUC15) orthologs by Western blot analysis using polyclonal anti-peptide antibodies against MUC15. Lane 1=bovine milk; lane 2=ovine milk; lane 3=caprine milk; lane 4=porcine milk; lane 5=buffalo cream; lane 6=human milk fat globule membrane.

Isolation of mucin 15 (MUC15) orthologs by reversed-phase HPLC chromatography (panels a, b, and c; 1-mL Resource column). Proteins were eluted with a gradient of 80% 2-propanol in 20% formic acid at 40°C (dotted line) and detected at 280nm (solid line). Samples: a) caprine milk fat globule membrane (MFGM) proteins eluted from a diethylaminoethyl (DEAE) column; b) Triton X-100-extractable ovine MFGM proteins, and c) human Triton X-100-extractable MFGM proteins. Analysis by SDS-PAGE (18%) and Western blot analysis (panels d, e, and f): d) lane 1=Triton X-100-extracted caprine MFGM proteins (periodic acid-Schiff (PAS)-stained); lane 2=PAS-stained caprine MUC15-containing fraction from the Resource column; lane 3=Western blot of isolated caprine MUC15 using polyclonal anti-bovine MUC15 antibodies; e) lane 1=PAS-stained Triton X-100-extracted ovine MFGM proteins; lane 2=PAS- and Coomassie-stained ovine MUC15-containing fraction; lane 3=Western blot of isolated ovine MUC15 using anti-peptide antibodies; f) lane 1=PAS- and Coomassie-stained human MUC15 containing fractions; lane 2=Western blot of isolated human MUC15 using anti-peptide antibodies; g)=alignment of N-terminal sequences of bovine, caprine, and ovine MUC15 using Biology WorkBench version 3.2; bovine MUC15 (AJ417816).

Expression profile of human mucin 15 (MUC15) using a human multiple expression (MTE) array. Following overnight hybridization of the MTE array with a radiolabeled MUC15 cDNA probe, the array was exposed to a phosphorimager screen. Tissues and cell types to which the probe hybridized are shown.

Alignment of mucin 15 (MUC15) orthologs showing conserved potential N-glycosylation sites (asterisks). Aligned species: chimpanzee, Pan troglodytes (XP_508334); human, Homo sapiens (CAD10624); rhesus monkey, Macaca mulatta (XP_001091253); bovine, Bos taurus (CAD10622); mouse, Mus musculus (Q8C6Z1); and rat, Rattus norvegicus (AAH83925)