Fig. 1.

Structures and DNA sequence preferences of USF1 and USF2 and proteins that interact with them. USF1 and USF2 contain nuclear localization sequences (NLS), as well as basic region (BR), HLH, and LZ domains in the CTD-specific region and a USR in the N-terminal domain. USF heterodimers preferentially associate with the E-box sequence CACGTGAC but also interact with pyrimidine-rich initiator elements in conjunction with transcription factor TFII-I. Proteins documented to interact with USF proteins are listed at the bottom (references are in brackets).