Cell-Type-Specific Splicing of Transcription Regulators and Ptbp1 by Rbfox1/2/3 in the Developing Neocortex

Area of Science:

• Neuroscience
• Molecular Biology
• Genetics

Background:

• The intricate mechanisms of alternative splicing in the developing brain, particularly how splicing regulators interact and affect transcription factors, remain largely unknown.
• Understanding cell-type-specific gene expression is crucial for deciphering developmental processes in the neocortex.

Purpose of the Study:

• To investigate the cross-talk between splicing regulators and transcription factors during neocortical development.
• To determine the extent of differential splicing in transcription regulators and its functional consequences.

Main Methods:

• Cell-type-specific RNA sequencing (RNA-Seq) was performed on the developing neocortex.
• Expression patterns of Rbfox genes (Rbfox1/2/3) and their impact on alternative splicing of transcription regulators were analyzed.
• Functional consequences of Rbfox ablation and specific splicing events were assessed through gene manipulation and migration studies.

Main Results:

• Variable expression of Rbfox1/2/3 genes was observed, correlating with enriched alternative splicing in transcription regulators.
• Rbfox proteins were found to induce neuronal splicing events in transcription regulators like Meis2 and Tead1, and affect Ptbp1 splicing.
• Simultaneous ablation of Rbfox1/2/3 disrupted neuronal isoform expression, impaired radial neuronal migration, and revealed cell-type-specific functions of Meis2 isoforms.

Conclusions:

• Transcription regulators undergo differential splicing between cell types in the developing neocortex, orchestrated by splicing factors like Rbfox.
• Splicing regulation of transcription factors plays a critical role in neuronal differentiation and migration during brain development.
• The study highlights a novel layer of gene regulation impacting neocortical development through alternative splicing of transcription factors.