[Regulator sequences in the kappa-chain gene expressed in the hybridoma PTF.02]

Two kappa genes, one (5.7 kb) from parental myeloma cells that were used for fusion, and the other (7.5 kb) from lymphocytes have been detected in the genome of PTF.02 hybridoma. Functionally important regions of the second gene were sequenced. In the 5'-region, positions and nucleotide sequences of the L-fragment, TAATA- and CAAT-boxes were established. Deca (dc)- and pentadecanucleotide (pd) sequences, obligatory for effective transcription of Kappa genes, were localized at the distance of 91 and 118 bp from the ATG initiating codon of the leader sequence. Together with a true pd, a shadow pd sequence was localized. This sequence was overlapped with the first sequence and shifted by one helical twist. The structure of the region of the enhancer localization was established. Comparison of this sequence with known consensus of the papova virus enhancer allows us to suggest the following structure of the enhancer core for kappa chains: TGTGGCTAA... 10 bp... TGTGGTTA. In the kappa gene under study, the variable fragment is linked to the J5 segment. In the latter, a point mutation C----G was found, to which a conservative substitution Ala - Gly in a hypervariable region of the chi-chain should correspond. Somatic mutations were also observed within the intron region adjacent to the J5 segment.