3D enhancer architecture coordinated by CTCF determines immune-related gene expression patterns via RNA polymerase II...

Area of Science:

• Genomics
• Immunology
• Molecular Biology

Background:

• CCCTC-binding factor (CTCF) organizes mammalian genomes into structural domains and loops.
• The precise role of CTCF in enhancer-promoter interactions, especially in immune cells, is not fully understood.

Purpose of the Study:

• To investigate the impact of CTCF depletion on 3D enhancer architecture and gene expression in activated CD4+ T cells.
• To elucidate the mechanisms by which CTCF influences enhancer-promoter interactions and transcriptional regulation in response to stimuli like JAK inhibitors.

Main Methods:

• Depletion of CTCF in activated CD4+ T cells.
• Analysis of 3D genome architecture and enhancer-promoter interactions.
• Assessment of active transcription, RNA polymerase II (RNAPII) pausing, and gene expression patterns.
• Evaluation of transcriptional responses to JAK inhibitors.

Main Results:

• CTCF depletion significantly reorganizes 3D enhancer architecture in CD4+ T cells.
• STAT5-bound super-enhancers maintain enhancer loops independently of CTCF during active transcription.
• Enhancer-promoter interactions are linked to RNAPII pause-release and require CTCF-dependent genome organization for immune gene expression.
• CTCF depletion reprograms CD4+ T cell responses to JAK inhibitors by altering the STAT5 enhancer network.

Conclusions:

• CTCF-mediated 3D genome organization is crucial for shaping immune-related gene expression in CD4+ T cells.
• Active transcription and RNAPII pause-release are key mechanisms in maintaining enhancer function, even upon CTCF loss.
• CTCF plays a significant role in regulating cellular responses to targeted therapies like JAK inhibitors by modulating enhancer networks.