Global Run-on Sequencing (GRO-Seq)

Area of Science:

• Molecular Biology
• Genomics
• Transcriptional Regulation

Background:

• Mature RNA levels (e.g., mRNAs) often do not accurately reflect active gene transcription due to post-transcriptional processing.
• Understanding nascent RNA is crucial for studying gene expression regulation at the transcriptional level.

Purpose of the Study:

• To describe a robust protocol for detecting low-abundance nascent RNA in mammalian cells using Global Run-on Sequencing (GRO-Seq).
• To enable genome-wide annotation of transcriptionally engaged RNA Polymerase II (RNAPII) positions, levels, and orientation.
• To provide mechanistic insights into transcriptional regulation, including promoter-proximal pausing, bidirectional transcription, and enhancer activity.

Main Methods:

• Global Run-on Sequencing (GRO-Seq) combines nuclear run-on assays with next-generation sequencing.
• The protocol is optimized for mammalian cells to detect nascent RNA from both coding and noncoding genomic regions.
• High sensitivity allows for the measurement of dynamic transcriptional responses.

Main Results:

• The described GRO-Seq protocol reliably detects low-abundant nascent RNA.
• It accurately maps RNAPII positions, levels, and orientation across the genome.
• The method facilitates the identification of transcriptionally active genomic regions.

Conclusions:

• GRO-Seq is a powerful tool for studying transcriptional regulation and dynamics in mammalian systems.
• The protocol is adaptable for various mammalian cell types and sensitive to external stimuli.
• This method enhances the understanding of genome-wide transcription and regulatory mechanisms.