Líffræðifélag Íslands - biologia.is
Líffræðiráðstefnan 2023
Höfundar / Authors: Kinga Demény, Sveinn Bjarnason, Pétur Orri Heiðarsson
Starfsvettvangur / Affiliations: 1. Háskóli Íslands
Kynnir / Presenter: Kinga Demény
Cellular differentiation requires the selective activation and silencing of genes. Pioneer transcription factors (pTFs) play a key role by binding and accessing previously inaccessible genomic regions. Despite the conserved DNA binding domain (DBD) within the Sox family, only Sox2 alters the chromatin landscape to the extent of affecting cell identity. This suggests that the differences in the intrinsically disordered regions (IDRs) flanking the DBD play a key role in chromatin remodelling.
As these regions are highly mobile, most classical methods are inherently incapable of detecting or capturing IDRs. Single-molecule Förster Resonance Energy Transfer (sm-FRET) is a powerful method to study IDRs by probing intra- and inter-molecular interactions at the nanoscale by mapping distances between specific dye pairs.
To study pTF-chromatin interactions, a defined in vitro chromatin system is vital. Strong nucleosome positioning sequences, like W601, yield stable nucleosomes but may obscure subtle dynamic interactions influencing pTF binding dynamics and kinetics. Using naturally occurring DNA sequences instead of engineered ones is therefore preferable. Still, their lower stability hinders single-molecule studies where low concentrations are to be used.
Our study demonstrates the effects of Sox2 binding to nucleosomes and the stabilisation of native-like nucleosome structures, marking the initial crucial steps toward developing a more physiologically relevant experimental system