Beta 2-microglobulin gene mutations: a study of established colorectal cell lines and fresh tumors.
The technique of single-strand conformation polymorphism (SSCP) was used to screen a series of 37 established colorectal cell lines, 22 fresh tumor samples, and 22 normal DNA samples for mutations in the beta 2-microglobulin gene. Exon 1 (including the leader peptide sequence) and exon 2 were screened separately. Six of 37 colorectal cell lines and 1 of 22 fresh tumors were shown to contain mutations, whereas no mutations were detected in the normal DNA samples. Sequencing of these mutations showed that an 8-bp CT repeat in the leader peptide sequence was particularly variable, since 3 of the cell lines and one fresh tumor sample have deletions in this region. In the related cell lines, DLD-1 and HCT-15, two similar mutations were identified, a C-->A substitution in codon 10 and a G-->T mutation in the splice sequence of intron 1. Expression of beta 2-microglobulin was examined using a series of monoclonal antibodies in an ELISA system. Reduced expression correlated with a mutation in one allele of beta 2-microglobulin, whereas loss of expression was seen in instances where a line was homozygous for a mutation or heterozygous for two mutations.
Bicknell
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DC
Cancer Immunology Laboratory, John Radcliffe Hospital, Headington, Oxford, United Kingdom.
Rowan
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A
Bodmer
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WF
D000595:Amino Acid Sequence; D001483:Base Sequence; D015179:Colorectal Neoplasms / Q000235:genetics*; D004273:DNA, Neoplasm; D005091:Exons; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D014407:Tumor Cells, Cultured; D001613:beta 2-Microglobulin / Q000235:genetics*
D004273:DNA, Neoplasm; D001613:beta 2-Microglobulin