Regulation of the Ig kappa-chain enhancer by the adenovirus E1A gene products. Repression in lymphoid cells, activation in fibroblasts.

Proteins encoded by early region 1A (E1A) regulate transcription of viral and cellular genes. The mechanism of this trans-activation is not understood, but is of considerable interest as an example of transcription regulation through a cellular intermediate. We have therefore studied the effect of E1A products on the activity of the kappa L chain gene promoter and enhancer. By using transient and stable transfections into lymphoid and nonlymphoid cells, we found that the E1A proteins have a pleiotropic effect on the regulation of the mouse kappa-chain gene enhancer. In lymphoid cells the E1A products repress kappa-chain enhancer, whereas in fibroblasts, the kappa-chain enhancer is activated by the E1A products whether the E1A gene is in an extrachromosomal location or stably integrated in the genome. Furthermore, a functional kappa-chain promoter, containing the octanucleotide and "TATA" sequences is needed in order to be transcribed in E1A-producing cells. This ability of E1A products to negatively and positively regulate kappa-chain transcription may reflect a more general phenomenon in which a given cellular protein could participate in a variety of different cellular controls.