An ACCC-containing protein-binding sequence in the neighbourhood of the decanucleotide recognition site of the immunoglobulin gene promoter.

The decanucleotide (dc) box TNATTTGCAT is an important functional element in the K light chain gene promoter and was shown to bind nuclear proteins. We now describe the binding of nuclear factor III to dc containing oligonucleotides and define a second protein binding site in the neighbourhood of dc which turned out to be recognized by a partially purified NFIII preparation but not by highly purified NFIII (abbreviations ref. 1). This site comprises an ACCC-containing sequence element. It was further characterized by the hydroxyl radical footprinting method which is applicable to 40 bp long oligonucleotides. The significance of the ACCC-containing sequence and of the previously described 15mer sequence pd is discussed.