Super-enhancers include classical enhancers and facilitators to fully activate gene expression

Area of Science:

• Molecular Biology
• Genetics
• Epigenetics

Background:

• Super-enhancers are critical regulatory elements controlling cell identity genes.
• They recruit transcription factors and co-activators like the Mediator complex.
• The distinct roles of multiple elements within a single super-enhancer are not fully understood.

Purpose of the Study:

• To investigate the functional roles of different regulatory elements within a multipartite super-enhancer.
• To determine if classical enhancers and facilitator elements have distinct contributions to gene activation.

Main Methods:

• Rebuilding the endogenous multipartite α-globin super-enhancer.
• Functional characterization of classical enhancers and facilitator elements.
• Assessment of Mediator recruitment, enhancer RNA transcription, and enhancer-promoter interactions.

Main Results:

• Super-enhancers contain functionally distinct classical enhancers and facilitator elements.
• Facilitator elements lack intrinsic enhancer activity but are essential for classical enhancer function.
• Absence of facilitators reduces Mediator recruitment, enhancer RNA transcription, and enhancer-promoter interactions.

Conclusions:

• Facilitator elements potentiate classical enhancer activity, ensuring robust target gene upregulation.
• These elements play a crucial role in maintaining cell identity through precise gene regulation.
• Facilitators exhibit functional hierarchy based on their position within the super-enhancer.