Upstream regulatory sequences of immunoglobulin genes are recognized by nuclear proteins which also bind to other gene regions.

The decanucleotide sequence (dc) TNATTTGCAT is an upstream regulatory sequence of immunoglobulin genes and occurs also upstream of certain other eukaryotic and prokaryotic genes (compiled in the accompanying paper). We now investigated the binding of proteins from nuclear extracts of a number of cell types and organisms to the dc sequence using a sensitive gel electrophoretic DNA binding assay. Binding studies with specifically designed oligonucleotides led to the following conclusions: the central T of the dc sequence can be altered with only a slight decrease of protein binding activity: the sequences in the neighborhood of dc have a positive or negative effect on the efficiency of protein binding; C-rich sequences which occur in many K chain promoters have a protein binding activity independent of dc; the dc binding protein(s) of human lymphoid cells elute from a Sephadex column in the 30.000-60.000 molecular weight range; dc binding proteins were found in nuclear extracts of lymphoid as well as non-lymphoid human and murine cell lines, of Xenopus oocytes, and of yeast cells. The finding of dc binding proteins in a wide variety of different organisms and the occurrence of dc-related sequences in the regulatory regions of several gene families point to a general role in the transcriptional regulation of the respective genes.