N4-acetylation of cytidine in mRNA plays essential roles in plants

Area of Science:

• Molecular Biology
• Plant Science
• Epigenetics

Background:

• RNA base modifications play a critical role in regulating gene expression and biological functions.
• Cytidine acetylation is a newly discovered RNA modification with potential implications for cellular processes.

Purpose of the Study:

• To investigate the occurrence and function of N4-acetylation of cytidine in plant RNA.
• To identify the enzymes responsible for RNA acetylation in plants and elucidate their role in development.

Main Methods:

• Liquid chromatography-tandem mass spectrometry (LC-MS/MS) to detect acetylated RNA.
• Acetylation-related immunoprecipitation sequencing (acRIP-seq) to identify acetylated transcripts.
• Analysis of Arabidopsis thaliana mutants lacking key acetyltransferase genes.

Main Results:

• Identified N4-acetylation of cytidine in various plant RNAs, including mRNA.
• Discovered two partially redundant enzymes, N-ACETYLTRANSFERASEs FOR CYTIDINE IN RNA (ACYR1 and ACYR2), responsible for RNA acetylation in vivo.
• Demonstrated that ACYR genes are essential for plant development, with mutations leading to embryo lethality and leaf development defects.
• Linked reduced RNA acetylation to the destabilization of the TOUGH transcript, impacting microRNA processing.

Conclusions:

• N4-acetylation of cytidine is a significant RNA modification in plants, influencing RNA function and stability.
• ACYR1 and ACYR2 are critical for RNA acetylation and play vital roles in plant development.
• This RNA modification pathway is essential for microRNA processing and likely affects numerous other biological processes in plants.