Sox7, Sox17 and Sox18 all belong to the SoxF family of transcription factors and have identical DNA binding domains, so they bind to identical DNA motifs (Francois et al., 2010). However, by forming homodimers (such as Sox18-Sox18) or heterodimers (such as Sox7-RBPJ, Sox17-OCT4 or Sox18-MEF2C), they are able to bind to distinct regions of DNA because they need to recognize and bind to two consecutive DNA motifs. This allows the transcription factors to both co-operate and work on their own. Overman et al. show that a small molecule called Sm4 (not shown) can disrupt protein-protein interactions involving Sox18, while having little impact on those involving Sox7 and Sox17.
FIGURE CREDIT: Il-Kug Kim, Injune Kim, Gou Young Koh.