Transcription factor that activates the LYN and BLK promoters. Appears to be required for the T-cell-receptor-mediated trans activation of HIV-2 gene expression. Binds specifically to two purine-rich motifs in the HIV-2 enhancer. Binds to the underphosphorylated form of RB. May interact with other transcription factors in order to regulate specific genes. Interacts with RUNX1. In fetal tissues, it is highly expressed in heart, lung liver and kidney, and weakly expressed in brain. In adult, it is highly expressed in pancreas, spleen, thymus and peripheral blood leukocytes, expressed at moderate levels in heart, placenta, lung, liver, skeletal muscle, kidney, prostate, ovary, small intestine and colon, and weakly expressed in brain and testis. Belongs to the ETS family.