[Regulation of transcription of immunoglobulin kappa genes in Xenopus laevis oocytes].

Recombinant plasmids containing the immunoglobulin kappa gene with deletions in the 5' and 3' regions of the gene having different position and orientation of the enhancer element were constructed. The plasmids were incubated with cell-free extracts prepared from lymphoid and non-lymphoid cells, and then injected into the nuclei of Xenopus laevis oocytes. Tissue-specific transcription of the V kappa gene was shown to be under control of factor(s) existing in lymphoid cells. The data reported in this paper allow to suggest that, along with the positive transcription control regions located in the 5' region of the gene and in the J-C intron, there is also a negative control region situated in the J-C intron as well. Possible role of the tissue-specific factors from lymphoid cells is to abolish the negative control.