[Immunoglobulin kappa-genes. Cloning, hybridization and structural analysis].

The principal problems in molecular and genetic immunology to be resolved are the structure of Ig-genes and the regulation of their expression. The isolation of mRNA for light and heavy Ig-chains would be a first step along this line. A combination of two approaches may be the best strategy in mRNA preparation. Affinity purification allows one to obtain pure mRNA in a one-step procedure whereas immunoprecipitation makes it possible to prepare mRNAs for both heavy and light immunoglobulin chains in considerable amounts. In the series of experiments, conditions for synthesis of long and short cDNA chains were elaborated and the clone containing the fragment of kappa-chain gene was isolated and characterized. This clone was used as a probe for hybridization with genomic DNA from myeloma and hybridoma cells. It was shown that both allelic genes on homologous chromosomes were rearranged in myeloma MOPC21 cells. The original cell line of hybridoma PTF02 contains the embryonic gene as well as the differentiated genes. However, only differentiated genes can be detected in a similar experiment conducted with the same hybridoma after passage on mice. In conclusion, the coordination of homologous and heterologous chromosome expression in B cells in discussed in terms of the feed-back control.