RNA Pol II-dependent transcription efficiency fine-tunes A-to-I editing levels

Area of Science:

• Epitranscriptomics
• Molecular Biology
• RNA Biology

Background:

• A-to-I RNA editing converts adenosine to inosine, altering RNA function and potentially causing disease.
• This editing is crucial in protein-coding regions and primarily occurs during transcription.

Purpose of the Study:

• To investigate the regulation of A-to-I RNA editing in the context of transcription and pre-mRNA processing.
• To understand how transcription factor MYC and pre-mRNA levels influence editing extent.

Main Methods:

• Studied A-to-I editing in relation to transcription rates and MYC activation.
• Compared editing levels between pre-mRNA and mRNA in cellular systems and mouse tissues.
• Utilized actinomycin D treatment in neuronal cells to assess transcription-dependent regulation.

Main Results:

• Transcription stimulation impacts A-to-I editing levels; MYC activation up-regulates editing, especially in suppressed transcripts.
• Low pre-mRNA synthesis and expression levels correlate with high editing rates.
• Significant differences in editing levels between pre-mRNA and mRNA were observed across targets and tissues, suggesting regulation during pre-mRNA splicing.

Conclusions:

• Pre-mRNA processing, particularly splicing, represents a key regulatory layer for A-to-I editing.
• Transcription rates and factors like MYC dynamically control A-to-I editing extent.
• Regulation of RNA editing is complex and influenced by both transcriptional and post-transcriptional events.