Specifically binds to the DNA sequence 5'-GGGACTTTCC-3' which is found in the enhancer elements of numerous viral promoters such as those of SV40, CMV, or HIV1. In addition, related sequences are found in the enhancer elements of a number of cellular promoters, including those of the class I MHC, interleukin-2 receptor, somatostatin receptor II, and interferon-beta genes. It may act in T-cell activation (By similarity). Interacts with TCF4. Expressed in heart, lung, skeletal muscle and liver. In the brain expressed in cerebral cortex, hippocampus, corpora amygdala and cerebellar cortex. At 13.5 dpc and 15.5 dpc expressed in anterior neural tube over primordial frontal cortex, spinal cord, dorsal root glanglia and developing skeletal muscle.