DIVERSE TRANSCRIPTION FACTORS ARE INVOLVED IN THE QUANTITATIVE REGULATION OF TRANSCRIPTIONAL ACTIVATION OF KAPPA-PROMOTERS

Immunoglobulin chi promoters show sequence divergence but conserved fu nction between different subgroups. Here we show that three separate 5 ' elements are required for synergistic stimulation of transcription w ith the decamer in a chi promoter. These sites are a 5' E-box, a 3' AT -rich region in the pentadecamer (pd) element, and the chi-Y element. Elf-1 is a novel chi-Y element ligand induced upon mitogenic stimulati on of resting B lymphocytes. Furthermore, the 5' E2A-like E-box in the pd element could be substituted by an upstream stimulatory factor mot if with conservation of function. Thus, the synergistic activation req uirements of chi transcription is strictly dependent on the quantitati ve presence of transcription factor-binding motifs 5' of the decamer, but these differ qualitatively in that they may bind an array of prote ins with conserved function.