Abstract
Human colon cancers differ in amounts of MUC2 mucin synthesized. However, it is unclear whether MUC2 encodes a single protein. When clones of human colon cancer cells were assayed with antibodies against the TR2 mucin repeat or non-TR2 epitopes, differences in relative expression of MUC2 proteins suggested multiple immunoreactive forms. RT-PCR analysis detected the established 15kbp MUC2 cDNA and a novel form (designated MUC2.1) lacking the MUC2 TR2 repeat. Sequencing of cDNA and genomic DNA indicated that MUC2.1 results from an alternate splice donor. RT-PCR with splice-junction spanning primers confirmed the expression of MUC2.1 mRNA. Anti-MUC2.1 antibody stained colon cancer cells and normal colon in a pattern different from TR2-specific antibody. The presence of MUC2.1 mucin may help us to explain previous conflicting reports that have attempted to correlate the relative abundance of MUC2 protein and/or mRNA with the biological behavior of colon cancer cells.
Publication types
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Alternative Splicing / genetics
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Amino Acid Sequence
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Antibodies, Monoclonal
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Base Sequence
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Cell Line, Tumor
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Cell Transformation, Neoplastic / genetics
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Cell Transformation, Neoplastic / metabolism
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Colonic Neoplasms / genetics
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Colonic Neoplasms / metabolism
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DNA Primers / genetics
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DNA, Complementary / genetics
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Epitopes / analysis
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Exons / genetics
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Gene Expression / genetics
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Humans
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Immunohistochemistry
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Introns / genetics
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Molecular Sequence Data
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Mucin-2
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Mucins / biosynthesis
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Mucins / genetics*
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Mucins / immunology
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Protein Isoforms / biosynthesis
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Protein Isoforms / genetics
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Protein Isoforms / immunology
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RNA, Messenger / analysis
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RNA, Messenger / biosynthesis
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Repetitive Sequences, Nucleic Acid / genetics
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Reverse Transcriptase Polymerase Chain Reaction
Substances
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Antibodies, Monoclonal
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DNA Primers
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DNA, Complementary
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Epitopes
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MUC2 protein, human
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Mucin-2
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Mucins
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Protein Isoforms
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RNA, Messenger
Associated data
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GENBANK/AF257165
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GENBANK/AF257166
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GENBANK/AF257167