Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark.
Copenhagen Plant Science Centre, University of Copenhagen, Frederiksberg, Denmark.
PLoS Genet. 2022 Sep 27;18(9):e1010386. doi: 10.1371/journal.pgen.1010386. eCollection 2022 Sep.
Adenosine bases of RNA can be transiently modified by the deposition of a methyl-group to form N6-methyladenosine (m6A). This adenosine-methylation is an ancient process and the enzymes involved are evolutionary highly conserved. A genetic screen designed to identify suppressors of late flowering transgenic Arabidopsis plants overexpressing the miP1a microProtein yielded a new allele of the FIONA1 (FIO1) m6A-methyltransferase. To characterize the early flowering phenotype of fio1 mutant plants we employed an integrative approach of mRNA-seq, Nanopore direct RNA-sequencing and meRIP-seq to identify differentially expressed transcripts as well as differentially methylated RNAs. We provide evidence that FIO1 is the elusive methyltransferase responsible for the 3'-end methylation of the FLOWERING LOCUS C (FLC) transcript. Furthermore, our genetic and biochemical data suggest that 3'-methylation stabilizes FLC mRNAs and non-methylated FLC is a target for rapid degradation.
RNA 的腺苷碱基可以通过沉积一个甲基基团而暂时被修饰，形成 N6-甲基腺苷（m6A）。这种腺苷甲基化是一种古老的过程，涉及的酶在进化上高度保守。一个旨在鉴定过表达 miP1a 微蛋白的转基因拟南芥晚花植物的抑制子的遗传筛选，产生了 FIONA1（FIO1）m6A-甲基转移酶的一个新等位基因。为了研究 fio1 突变体植物的早花表型，我们采用了 mRNA-seq、Nanopore 直接 RNA-seq 和 meRIP-seq 的综合方法，以鉴定差异表达的转录本和差异甲基化的 RNA。我们提供的证据表明，FIO1 是负责 FLOWERING LOCUS C（FLC）转录物 3'-末端甲基化的难以捉摸的甲基转移酶。此外，我们的遗传和生化数据表明，3'-甲基化稳定了 FLC mRNA，而非甲基化的 FLC 是快速降解的靶标。
