Epigenome Editing

Abstract

The regulation of chromatin structure and gene expression depends substantially on a dynamic and intricate layer of biological and chemical information that constitutes the epigenome. This epigenetic layer of information holds fundamental clues to the molecular mechanisms, not yet fully understood, by which a genotype can influence and configure a specific phenotype. A profound understanding of the molecular underpinnings of epigenetic processes is, thus, essential to wield deliberate spatiotemporal control of gene activation and repression. However, only recently has the technology required to adequately probe the functional significance of specific epigenetic mechanisms become available. This chapter provides an overview of modern epigenome editing systems, including zinc finger proteins, TAL effectors, and CRISPR-Cas systems. It highlights the use of biotechnological tools to investigate the role of DNA and histone post-translational modifications as well as regulatory RNAs to manipulate specific patterns of gene expression. This chapter further discusses the technological limitations that have limited our ability to elucidate epigenetic mechanisms in local and genome-wide contexts.

Epigenetic Modulators as Therapeutic Agents in Cancer

“…Precision is one of the main issues. For example, a study's focus of acetylation of histone H3 at lysine 27 through the p300 enzyme shows the potential error in the system, raising concerns about potential off-target effects and antibody specificity [84].…”

Improving CRISPR Genome Editing by Engineering Guide RNAs

“…To improve CRISPR as a genetic modifier, this technology can be engineered in two ways: protein engineering of the effector nucleases, Cas9 or Cas12a (formerly Cpf1); and gRNA engineering. Engineering the catalytically inactive dCas [7] has made it feasible for the dead nucleases to be fused to a variety of functional enzymes for base editing [8][9][10][11], epigenetic regulations [12,13], transcriptional inhibition (CRISPRi)/activation (CRISPRa) [14,15], and library screening [16]. Moreover, Cas9 variants created by rational design or directed evolution have enabled highfidelity gene targeting [17][18][19][20]; as such, systematic review articles covering the adopted engineering methods, applications, and prospects for Cas engineering are available [6,21,22].…”