Nucleic acid and protein sequences of phosphocholine-binding light chains.

An 18-kilobase DNA fragment containing the sequence coding for both the variable and constant regions of the S107 mouse immunoglobulin light chain was cloned from total cellular DNA. The complete nucleotide sequence of the kappa-chain variable-region gene is reported. Determination of the amino acid sequence encoded by the DNA is found to be identical to the protein sequence of the T15 light chain through residue 88. Direct sequence analysis confirmed that the J1 joining segment is used in the recombination event producing the active kappa light chain gene.