Long-range enhancer-controlled genes are hypersensitive to regulatory factor perturbations.

Area of Science:

• Genomics
• Molecular Biology
• Gene Regulation

Background:

• Enhancers regulate cell-type-specific gene activation, often located far from gene promoters.
• The specific factors orchestrating long-range enhancer-gene communication remain largely unknown.

Purpose of the Study:

• To identify factors essential for distal enhancer function.
• To understand how enhancer distance influences gene regulation and cellular specificity.

Main Methods:

• Utilized enhancer distance-controlled reporter screens to identify candidate regulatory factors.
• Employed activity-by-contact predictions for genome-wide gene classification based on enhancer distance.
• Performed gene depletion and perturbation experiments, including BET inhibitor JQ1 treatment.

Main Results:

• Cohesin and mediator complexes are specifically required for long-range enhancer-mediated gene activation.
• Cohesin actively represses short-range gene activation and prioritizes distal over proximal gene targets when enhancers are shared.
• Genes regulated by long-range enhancers exhibit distinct features making them sensitive to regulatory protein perturbations and BET inhibitors.
• Distal enhancers predominantly control tissue-restricted genes and function as strong enhancers.

Conclusions:

• Cohesin and mediator are key regulators of long-range gene activation, with cohesin playing a dual role in repressing short-range activation.
• The distinct features of distal enhancers, rather than just their distance, dictate gene regulation sensitivity.
• Increasing intervening sequence length can restrict gene expression to specific cell types by optimizing trans-factor environments.