NAT10 and N⁴-acetylcytidine restrain R-loop levels and related inflammatory responses

Area of Science:

• Molecular Biology
• Epigenetics
• RNA Modification

Background:

• N4-acetylcytidine (ac4C) is an RNA modification deposited by N-acetyltransferase 10 (NAT10).
• NAT10 is implicated in aging and cancer, highlighting its biological significance.
• R-loops, implicated in mutagenesis, are a focus of recent research.

Purpose of the Study:

• To comprehensively survey ac4C modification across diverse RNA types.
• To investigate the role of NAT10 in R-loop regulation and its impact on cellular processes.
• To explore the link between ac4C, R-loops, and inflammatory responses.

Main Methods:

• Metabolic labeling and next-generation sequencing (NGS) for ac4C profiling.
• ac4C antibody-based techniques for cellular and molecular analysis.
• Analysis of NAT10 knockout (KO) cells to assess NAT10-dependent modifications and R-loops.

Main Results:

• NAT10-dependent ac4C modification is abundant in rRNA and specific tRNAs, but low in mRNA.
• NAT10-KO cells exhibit an inflammatory signature and mutagenesis at transcriptionally active sites.
• R-loops are ac4C-acetylated in a NAT10-dependent manner, and NAT10 restrains R-loop levels.
• ac4C-unmodified RNAs, potentially from R-loops, accumulate in endosomal structures, inducing inflammation.

Conclusions:

• NAT10 plays a critical role in ac4C modification across various RNA types.
• NAT10 regulates R-loop homeostasis, influencing gene expression and genomic stability.
• Dysregulation of ac4C and R-loops by NAT10 may contribute to inflammatory responses, aging, and cancer.