Engineered Chromatin Remodeling Proteins for Precise Nucleosome Positioning

Abstract

Summary: Regulation of chromatin structure is essential for controlling access of DNA to factors that require association with specific DNA sequences. Here we describe the development and validation of engineered chromatin remodeling proteins (E-ChRPs) for inducing programmable changes in nucleosome positioning by design. We demonstrate that E-ChRPs function both in vitro and in vivo to specifically reposition target nucleosomes and entire nucleosomal arrays. We show that induced, systematic positioning of nucleosomes over yeast Ume6 binding sites leads to Ume6 exclusion, hyperacetylation, and transcriptional induction at target genes. We also show that programmed global loss of nucleosome-free regions at Reb1 targets is generally inhibitory with mildly repressive transcriptional effects. E-ChRPs are compatible with multiple targeting modalities, including the SpyCatcher and dCas9 moieties, resulting in high versatility and enabling diverse future applications. Thus, engineered chromatin remodeling proteins represent a simple and robust means to probe and disrupt DNA-dependent processes in different chromatin contexts. : Donovan et al. develop a versatile approach to alter local or genome-wide nucleosome positions in vivo through engineered chromatin remodeling proteins (E-ChRPs). These alterations in chromatin structure affect downstream processes including histone modification and transcription. E-ChRPs represent a powerful method of investigating the causes and consequences of chromatin states. Keywords: chromatin remodeling, transcription factors, dCas9, targeted nucleosome positioning, nucleosome, chromatin binding, chromatin engineering