ac4C modification of mRNA is required for plant development

Wang et al. reveal the wide occurrence and biological function of N4-acetylcytidine in plant mRNA.

Huijie Liu and Mingjia Chen

College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, P.R. China

Background: Eukaryotic mRNA harbors more than 10 different chemical modifications, most of which are involved in many cellular activities such as RNA processing, RNA degradation, and translation. These chemical modifications are installed by “writer” proteins on pre-mRNA. N4-acetylcytidine (ac4C), the only known type of RNA acetylation modification, has recently been reported in mammalian mRNA. This modification is introduced by a single-copy acetyltransferase NAT10 and promotes translation efficiency.

Question: Does ac4C modification widely exist in plant mRNA and what are the biological functions of this chemical modification?

Findings: Our data demonstrate the wide occurrence of ac4C modification on RNAs from several vascular plants. Employing acRIP-seq, we mapped the distribution of ac4C modifications in Arabidopsis thaliana. We also show that Arabidopsis RNAs are acetylated by N-ACETYLTRANSFERASEs FOR CYTIDINE IN RNA 1 (ACYR1) and ACYR2, which are homologs of human NAT10. A double null mutation is embryo lethal, while abolishing three of the four ACYR alleles leads to defects in vegetative development. This phenotypic alteration is caused by the accelerated degradation of TOUGH transcript, a component of miRNA biogenesis, when its ac4C levels are reduced.

Next steps: The identification and characterization of ac4C in plant RNA give rise to the field of RNA modification and open up many research questions. Are any other proteins involved in ac4C formation and/or removal? Does ac4C modification participate in other developmental processes and/or environmental stimuli? What are the molecular mechanisms of ac4C modification regulating the target transcripts?

Wenlei Wang, Huijie Liu, Feifei Wang, Xiaoye Liu, Yu Sun, Jie Zhao, Changhua Zhu, Lijun Gan, Jinping Yu, Claus-Peter Witte, Mingjia Chen. (2023). N4-acetylation of cytidine in (m)RNA plays essential roles in plants.