Poster Presentation 50th Lorne Proteins Conference 2025

How do chromatin readers modulate the activity of chromatin remodellers? (#309)

Clement Luong 1 , Susav Pradhan 1 , Joel Mackay 1
  1. School of Life and Environmental Science, University of Sydney, Sydney, NSW, Australia

Eukaryotic life has evolved diverse methods to manipulate their genetic information. Many of these methods involve recognition and modulation of the DNA that transcends the genetic code itself. Chromatin remodelling enzymes are a prominent class of proteins that manipulate genetic material by sliding DNA against histone octamers to alter gene accessibility.

Chromodomain helicase DNA binding protein 4 (CHD4) is an essential ATP-dependent chromatin remodeller that operates broadly in complex animals. Despite its significance, the mechanisms that regulate CHD4 activity remain unclear. It is known, however, that CHD4 can interact directly with members of the highly conserved bromodomain and extra-terminal domain (BET) family of proteins. BET proteins ‘read’ acetyl-lysine on histones and other proteins and disruption of their normal function is a hallmark of several cancers.

We present work that begins to illuminate the mechanistic and functional connection between CHD4 and BET-family proteins. Our FRET-based assays show that the three ubiquitous BET proteins play functionally distinct roles in regulating CHD4 activity in lieu of their strong homology. In conjunction with these established workflows, we also combine single molecule fluorescence microscopy and live-cell imaging to investigate the effects of these biochemical interactions at a chromatin and cellular level, building on our fundamental understanding of protein behaviour. The combination of these techniques allows us to make headway into understanding the mechanisms that govern transcriptional regulation.