Dissecting Tissue-Specific Super-Enhancers by Integrating Genome-Wide Analyses and CRISPR/Cas9 Genome Editing

AbstractRecent advances in genome-wide sequencing technologies have provided researchers with unprecedented opportunities to discover the genomic structures of gene regulatory units in living organisms. In particular, the integration of ChIP-seq, RNA-seq, and DNase-seq techniques has facilitated the mapping of a new class of regulatory elements. These elements, called super-enhancers, can regulate cell-type-specific gene sets and even fine-tune gene expression regulation in response to external stimuli, and have become a hot topic in genome biology. However, there is scant genetic evidence demonstrating their unique biological relevance and the mechanisms underlying these biological functions. In this review, we describe a robust genome-wide strategy for mapping cell-type-specific enhancers or super-enhancers in the mammary genome. In this strategy, genome-wide screening of active enhancer clusters that are co-occupied by mammary-enriched transcription factors, co-factors, and active enhancer marks is used to identify bona fide mammary tissue-specific super-enhancers. The in vivo function of these super-enhancers and their associated regulatory elements may then be investigated in various ways using the advanced CRISPR/Cas9 genome-editing technology. Based on our experience targeting various mammary genomic sites using CRISPR/Cas9 in mice, we comprehensively discuss the molecular consequences of the different targeting methods, such as the number of gRNAs and the dependence o...

Source: Journal of Mammary Gland Biology and Neoplasia - October 6, 2018 Category: Cancer & Oncology Source Type: research