GRID-seq for comprehensive analysis of global RNA-chromatin interactions

Area of Science:

• Molecular Biology
• Genomics
• Epigenetics

Background:

• Chromatin in eukaryotic nuclei interacts extensively with various RNA species.
• Understanding these RNA-DNA interactions is crucial for deciphering gene regulation.
• Existing methods have limitations in controlling for nonspecific interactions.

Purpose of the Study:

• To present a detailed protocol for Global RNA Interactions with DNA by deep sequencing (GRID-seq).
• To enable unbiased identification of the entire repertoire of chromatin-associated RNAs.
• To provide a computational pipeline (GridTools) for accurate data analysis and interpretation.

Main Methods:

• GRID-seq utilizes in situ capture of RNA-DNA interactions in fixed nuclei.
• A bivalent linker ligates proximity-based RNA and DNA molecules.
• The protocol includes nuclei preparation, chromatin fragmentation, ligation, PCR amplification, and sequencing.

Main Results:

• GRID-seq identifies both coding and non-coding RNAs (ncRNAs) interacting with genomic elements.
• Interactions are frequently observed at tissue-specific promoters and enhancers, particularly super-enhancers.
• A global promoter-enhancer connectivity map can be deduced from the identified interactions.

Conclusions:

• GRID-seq offers an unbiased approach to map chromatin-associated RNAs and their genomic interactions.
• The method provides a robust way to study RNA's role in organizing chromatin.
• GRID-seq, with its integrated computational tools, facilitates the study of RNA-genome interactions for researchers with varying bioinformatics expertise.