THE ROLE OF C-MYB OR A RELATED FACTOR IN REGULATING THE T-CELL RECEPTOR-GAMMA GENE ENHANCER

An enhancer has been localized 3 kb downstream of the C gamma 1 gene s egment of the murine TCR-gamma locus. One element, the gamma 3 site, h as been shown to be critical for its functional activity. Here we have determined that Myb-related transcription factors bind to the gamma 3 site and appear to be critical for the full activity of the TCR-gamma enhancer, c-myb products can transactivate the gamma 3 site in cell l ines that do not ordinarily support enhancer activity of the gamma 3 s ite. Mutations in the myb site or an adjacent site for core-binding fa ctor(s) prevent transactivation. c-myb expression in various cell line s is consistent with their Capacity to activate the gamma 3 enhancer e lement using transient transfection assays. Therefore, c-Myb or a rela ted factor appears to play an important role in regulating the murine TCR-gamma enhancer.