Regulation of kappa immunoglobulin gene transcription in vitro.

An in vitro transcription system has been established with a whole-cell extract from the human Burkitt's lymphoma, Daudi, cell line. The B cell extract has been compared with a HeLa cell extract in an effort to study lymphocyte-specific regulatory factors of kappa light chain gene transcription. Both extracts were capable of transcribing Vk genes and other RNA polymerase II dependent genes. Alpha-amanitin at [0.1 micrograms/ml] completely inhibited the accumulation of transcripts in both systems. At low DNA template concentrations the kappa intronic enhancer stimulated Vk promoter transcription 3-7 fold in B cell extracts. The enhancer-dependent transcription was abolished by excising the enhancer from the test plasmid with Eco R1. Both Vk promoter and enhancer-dependent transcription in HeLa extracts was undetectable at low [DNA]. These results demonstrate that kappa enhancer stimulation of Vk transcription in vitro is observed in B cell extracts only under conditions of low DNA template concentration.