The retroviral oncogene qin codes for a protein that belongs to the winged helix family of transcriptional regulators. The Qin protein is localized in the nucleus and binds to the same DNA consensus sequence as rat brain factor 1 (BF-1). Cellular Qin shows greater affinity to DNA than does viral Qin. Alone or fused to the DNA-binding domain of the yeast GAL4 protein, both Qin proteins act as transcriptional repressors. The major transcriptional repression domain maps to the region of amino acids 252-395 of viral Qin.