Figure 3.

Signal transducer and activator of transcription (Stat) binding to DNA. In this two-dimensional model, the heterodimerized or homodimerized Stat molecule binds to the appropriate DNA sequence via a 'C clamp' structure. Note that in addition to the specificity controlled by the DNA binding domain, other regions of the Stat molecule may also be important in DNA interactions. Tetramerization of the Stats may allow for an even greater degree of stability in DNA binding to adjacent imperfect Stat binding sites; this is mediated by the Stat amino-terminus (not shown). Also not shown in this illustration is the Stat transcriptional activation domain.