A tighter grip on gene expression.

Cells rely on precise gene regulation to produce specific proteins exactly when needed. Central to this are enhancers and promoters, DNA sequences that dictate the location, timing, and intensity of gene expression. According to the established model, these sequences are interpreted by transcription factors bearing domains that bind to specific sites within enhancers and promoters. Once bound, transcription factors recruit cofactors that transmit regulatory signals to the machinery responsible for RNA synthesis. These cofactors remodel chromatin, mediate protein interactions, or perform other tasks that regulate gene expression (1). However, this model seems to have missed an important and conceptually distinct function. On page 43 of this issue, Bianchi et al. (2) report a previously unidentified regulator that acts as a molecular "grip" to stabilize transcription factors at DNA binding sites across the human genome. [ABSTRACT FROM AUTHOR]