The macrophage and B cell-specific transcription factor PU.1 is related to the ets oncogene.

We have isolated a cDNA clone, PU.1, that codes for a new tissue-specific DNA binding protein. Analysis of the binding site by methylation interference and DNAase 1 protection revealed that the PU.1 protein recognized a purine-rich sequence, 5'-GAGGAA-3' (PU box). The PU.1 protein was shown to be a transcriptional activator that is expressed in macrophages and B cells. cDNA constructions used to generate proteins lacking portions of either the amino- or carboxy-terminal ends of the PU.1 protein placed the DNA binding domain in the highly basic carboxy-terminal domain of the protein. The amino acid sequence in the binding domain of PU.1 has considerable identity with proteins belonging to the ets oncogene family.