REST elevation-dependent chromatin remodeling and alternative Grk6 transcript synthesis hyperactivates Cxcr4-Sdf1...

Area of Science:

• Neuroscience
• Molecular Biology
• Developmental Biology

Background:

• RE1 Silencing Transcription Factor (REST) is a known repressor of genes crucial for neurogenesis.
• Cerebellar granule cell progenitors (CGNPs) migration is vital for cerebellar development and relies on pathways like C-X-C motif receptor 4 (Cxcr4) signaling.

Purpose of the Study:

• To investigate the role of REST in regulating CGNP migration and transcript diversity.
• To elucidate the molecular mechanisms by which REST influences Cxcr4 signaling and CGNP behavior.

Main Methods:

• Conditional REST elevation in REST^TG mice.
• Analysis of CGNP migration, foliation, and Cxcr4 signaling.
• RNA sequencing and multiomic analyses to identify transcriptomic changes and regulatory elements.
• Structural modeling of G-protein-coupled receptor kinase-6 (Grk6) isoforms.
• Pharmacological inhibition of enhancer of zeste (Ezh2).

Main Results:

• Conditional REST elevation in CGNPs perturbed cerebellar foliation and increased cell migration.
• REST controlled transcript diversity, including alternative splicing of the Cxcr4 regulator Grk6, leading to upregulation of an exon 10a-lacking isoform (Grk6-207).
• Grk6-207 expression hyperactivated Cxcr4 signaling and enhanced CGNP chemotaxis, suggesting impaired signaling desensitization.
• REST elevation increased chromatin accessibility at the Grk6 exon10a-10b junction, promoting exon 10a exclusion.
• Enhancer of zeste homolog 2 (Ezh2) was identified as a key mediator, showing increased occupancy at the Grk6 locus and regulating Grk6-207 expression and CGNP migration.

Conclusions:

• REST plays a novel role in regulating transcript diversity and exon skipping during neurogenesis.
• REST-mediated alternative splicing of Grk6 significantly impacts Cxcr4 signaling and CGNP migration.
• Ezh2 acts downstream of REST to control Grk6 alternative splicing and subsequent CGNP migration, highlighting a new regulatory axis in cerebellar development.