Preparation and characterization of Arabidopsis thaliana nucleosome core particles containing the histone variant H2A.Z

Abstract

Histones perform a fundamental role in constituting the genetic structure of organisms. Histone variants replace some of these canonical histones, altering the nucleosome structure, leading to varying interactions within the constituent biomolecules and specialization of functions across species. The presence of histone variants and the characteristic changes to them compared to canonical histones have been implicated in structural and functional modifications and stability of DNA and genome as a whole, regulation of transcription in various cells, distribution of nucleosome arrangement along the genetic code, and DNA repair. H2A.Z is a histone variant replacing H2A. Since its discovery decades ago, it has been discovered across a wide variety of living organisms, from simple protozoans and yeasts to highly advanced organisms like plants and even mammals like humans. This histone variant is the most evolutionarily conserved variant, showing a sequence similarity of ~90% across this aforementioned organism range. Despite having just close to 60% sequence similarity with its canonical counterpart, the occurrence of this histone variant being this widespread and conserved has great implications in functionality. H2A.Z has been implicated in functions such as transcriptional regulation, chromosome regulation, and nucleosome stability. Arabidopsis thaliana, despite being a well-documented plant, studies on this variant from the plant are scarce. The focus of this thesis is, hence, on the preparation and characterization of A. thaliana nucleosome core particles containing H2A.Z. This work is expected to open up further research on understanding nuances due to H2A.Z incorporation in the structure and functional attributes of plant nucleosomes.