Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1995-7-17
pubmed:abstractText
The affinity maturation of antibodies is driven by somatic hypermutation which is localized to specific segments of the coding genes. The information available on this process derives from studies in vivo. With the intention of developing new approaches, we have constructed a fusion gene between a kappa chain and a selectable neomycin resistance gene, neor. The neor gene, which includes the SV40 small t intron and polyadenylation site, but not the upstream elements nor its first 12 amino acids, is an in-frame substitution of the FR2-CDR3 fragment of a rearranged V kappa OX1-J kappa 5 gene. Expression of neor activity is therefore dependent on the upstream immunoglobulin sequence. A stop codon was placed in the CDR1 region so that only mutants survive treatment with geneticin sulphate (G418). The effectiveness of the system was tested by transfecting the NS0 myeloma cell line and isolating spontaneous mutants. Neomycin-resistant clones arose at an estimated rate of 1 x 10(-8)/cell division, and over 90% were authentic structural mutants. Unlike the somatic hypermutations, the majority arose by in-frame deletions including the stop codon, although up to 30% involved a point mutation. The reporter gene was then modified by substituting all the sequences downstream of the J kappa 5 with others known to be required for full hypermutation in vivo. Different cell lines were transfected and G418-resistant clones analyzed. No significant increase in the rate of reversion or in the generation of point mutations versus deletions was detected, even using conditioned culture medium. In the presence of azacytidine however, a mutant involving multiple events (single base addition and deletion plus two point mutations) was detected. The reporter gene system therefore seems suitable to test culture conditions and modifications of the host cells aimed at the derivation of an in vitro assay of somatic hypermutation.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0022-2836
pubmed:author
pubmed:issnType
Print
pubmed:day
9
pubmed:volume
249
pubmed:geneSymbol
V kappa Ox1-J kappa 5
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
555-63
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:7783211-Amino Acid Sequence, pubmed-meshheading:7783211-Animals, pubmed-meshheading:7783211-B-Lymphocytes, pubmed-meshheading:7783211-Base Sequence, pubmed-meshheading:7783211-Cell Line, pubmed-meshheading:7783211-Cloning, Molecular, pubmed-meshheading:7783211-DNA, Recombinant, pubmed-meshheading:7783211-DNA Mutational Analysis, pubmed-meshheading:7783211-Drug Resistance, Microbial, pubmed-meshheading:7783211-Gene Rearrangement, B-Lymphocyte, Light Chain, pubmed-meshheading:7783211-Genes, Immunoglobulin, pubmed-meshheading:7783211-Genes, Reporter, pubmed-meshheading:7783211-Mice, pubmed-meshheading:7783211-Molecular Sequence Data, pubmed-meshheading:7783211-Mutation, pubmed-meshheading:7783211-Neomycin, pubmed-meshheading:7783211-Polymerase Chain Reaction, pubmed-meshheading:7783211-Transfection
pubmed:year
1995
pubmed:articleTitle
A reporter gene to analyse the hypermutation of immunoglobulin genes.
pubmed:affiliation
Medical Research Council Laboratory of Molecular Biology, Cambridge, UK.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't