title: Cloning of an immunoglobulin variable region gene from mouse embryo.
abstract: A 4.8-kilobase DNA fragment carrying an immunoglobulin gene coding for a mouse lambda chain variable region (Vlambda gene) was enriched about 350-fold from a total endonuclease  EcoRI digest of embryonic DNA by a combination of preparative agarose gel electrophoresis of double-stranded DNA and CsCl density gradient centrifugation of R-loops formed with a purified lambda chain mRNA. DNA fragments thus enriched for the immunoglobulin gene were inserted in vitro in the middle of the genome of the vector phage lambdagt Wam  403, Eam 100, Sam 100 by use of the EcoRI cohesive ends. Transfection of CaCl2-treated Escherichia coli 803 [rk-, mk- (lacking restriction and modification systems for K-12)] with such hybrid DNA and subsequent screening of about 4000 plaques by in situ hybridization with purified 125I-labeled lambda chain mRNA led to isolation of a clone that carries a Vlambda gene (lambdagtWES-Ig 13). Electron microscopy of R-loops confirmed the presence of sequences homologous to part of the lambda chain mRNA in its 5'-end.
mesh_terms: D000818:Animals; D001666:Binding Sites, Antibody; D002874:Chromosome Mapping; D002999:Clone Cells; D003090:Coliphages / Q000378:metabolism*; D011088:DNA Ligases / Q000378:metabolism; D004274:DNA, Recombinant / Q000378:metabolism*; D004622:Embryo, Mammalian; D004926:Escherichia coli / Q000378:metabolism*; D005796:Genes; D007147:Immunoglobulin Light Chains / Q000096:biosynthesis*; D007135:Immunoglobulin Variable Region; D007146:Immunoglobulin lambda-Chains / Q000096:biosynthesis*; D051379:Mice; D008854:Microscopy, Electron; D009693:Nucleic Acid Hybridization; D014162:Transfection
chemical_list: D004274:DNA, Recombinant; D007147:Immunoglobulin Light Chains; D007135:Immunoglobulin Variable Region; D007146:Immunoglobulin lambda-Chains; D011088:DNA Ligases