RNA helicase-dependent gene looping impacts messenger RNA processing

Area of Science:

• Molecular Biology
• Gene Regulation
• Chromatin Dynamics

Background:

• DDX5 and DDX17 are DEAD-box RNA helicases involved in gene expression.
• Their precise roles in transcription and splicing are not fully understood.
• These helicases are crucial for regulating RNA processing events.

Purpose of the Study:

• To investigate the function of DDX5 and DDX17 in human cells.
• To elucidate the mechanisms by which these helicases control gene expression.
• To explore the interplay between RNA helicases, CTCF, and chromatin structure.

Main Methods:

• Transcriptome analysis of DDX5/DDX17-depleted human cells.
• In silico analyses and experimental validation in cultured cells.
• Chromatin immunoprecipitation and gene looping assays.

Main Results:

• DDX5/DDX17 depletion caused widespread deregulation of splicing and 3' end processing.
• CTCF binds to DDX5/DDX17-dependent exons, particularly those with high GC content and RNA Polymerase II density.
• DDX5/DDX17-dependent chromatin loops connect regulated exons to promoters, influencing alternative splicing and polyadenylation.

Conclusions:

• DDX5 and DDX17, in conjunction with CTCF, regulate gene expression through RNA helicase-dependent chromatin looping.
• Chromatin folding mediated by DDX5/DDX17 impacts pre-messenger RNA processing.
• These findings reveal a novel mechanism linking RNA helicases, chromatin organization, and RNA processing.