FIG. 9.

Model for SATB1-CDP interaction in different mouse tissues. The large cylinders represent CDP protein, whereas the smaller, dark cylinders represent SATB1. CDP may be inactivated for DNA binding by association with a single molecule of SATB1. Alternatively, binding of SATB1 to one of three possible sites within CR1, CR2, or the homeodomain may alter the specificity of CDP binding to different promoters. The large box represents the MMTV LTR that is divided into U3, R, and U5 domains. Transcription is initiated at the U3-R border of the 5′ LTR within the MMTV provirus. Upstream of the transcription initiation site are two regions termed the promoter-proximal and promoter-distal NREs (pNRE and dNRE, respectively). For simplicity, the binding of a single SATB1 or CDP molecule to the pNRE or dNRE is shown, although at least two binding sites each for SATB1 and CDP are located within the pNRE (59).