THE INTRONIC IMMUNOGLOBULIN CHI GENE ENHANCER ACTS INDEPENDENTLY ON REARRANGEMENT AND ON TRANSCRIPTION

It is not known which cis-acting elements regulate kappa gene rearrang ement. However, the onset of rearrangement coincides with the onset of transcription suggesting that common regulatory elements are used.We have investigated the role of the intronic enhancer on rearrangement u sing mice transgenic for kappa minigenes. The rabbit kappa enhancer, w hich is defective in activation of transcription in mouse cells, allow s a high level of rearrangement. However, transgenes which possess no enhancer region at all are rearranged a hundred times less compared to transgenes which possess the rabbit enhancer. Our results suggest tha t while the enhancer region can activate rearrangement as well as tran scription, its action on both phenomena can be uncoupled.