The three Rs of transcription: recruit, retain, and recycle

Abstract

The dynamic protein interactions required for transcription are functionally important yet poorly understood; in this issue of Molecular Cell, Zobeck et al. (2010) resolve the sequential recruitment and selective recycling of transcription factors at an actively transcribing locus in Drosophila.

Figure 1. Sequential recruitment and selective retention of transcription factors at the Hsp70 locus after heat shock

(A) Heat shock induces sequential recruitment of TFs to Hsp70, beginning with HSF. Additional TFs are recruited in synchronous waves across independent nuclei and to stoichiometric excess over chromatin binding sites. (B) FRAP data demonstrate that TFs are selectively retained at the Hsp70 loci throughout HS. PARP activity is required for TF retention in this “transcription compartment,” possibly through the formation of a matrix of polymerized ADP-ribose. This matrix could participate in TF retention and recycling by affinity-based retention of TFs for the ADP-ribose polymers, formation of a porous barrier, or some combination of both models.