N6-methylated adenine (m6A) is the most frequent posttranscriptional modification in eukaryotic mRNA. Turnover of RNA generates N6-methylated AMP (N6-mAMP), which has an unclear metabolic fate. We show that Arabidopsis thaliana and human cells require an N6-mAMP deaminase (ADAL, renamed MAPDA) to catabolize N6-mAMP to inosine monophosphate (IMP) in vivo by hydrolytically removing the aminomethyl group. A phylogenetic, structural, and biochemical analysis revealed that many fungi partially or fully lack MAPDA, which coincides with a minor role of N6A-RNA methylation in these organisms. MAPDA likely protects RNA from m6A mis-incorporation. This is required because eukaryotic RNA polymerase can use N6-mATP as a substrate. Upon abrogation of MAPDA, root growth is slightly reduced, and the N6-methyladenosine, N6-mAMP, and N6-mATP concentrations are increased in Arabidopsis. Although this will potentially lead to m6A mis-incorporation into RNA, we show that the frequency is too low to be reliably detected in vivo. Since N6-mAMP was several fold more abundant than N6-mATP in MAPDA mutants, we speculate that additional molecular filters suppress the generation of N6-mATP. Enzyme kinetic data indicate that adenylate kinases represent such filters being highly selective for AMP versus N6-mAMP phosphorylation. We conclude that a multilayer molecular protection system is in place preventing N6-mAMP accumulation and salvage.
%0 Journal Article
%1 Chen2018
%A Chen, Mingjia
%A Urs, Mounashree J
%A Sánchez-González, Ismael
%A Olayioye, Monilola A
%A Herde, Marco
%A Witte, Claus-Peter
%D 2018
%I American Society of Plant Biologists
%J The Plant cell
%K 2018 izi olayioye
%P tpc.00236.2018
%R 10.1105/tpc.18.00236
%T m6A RNA Degradation Products are Catabolized by an Evolutionarily Conserved N6-methyl-AMP Deaminase in Plant and Mammalian Cells.
%U http://www.ncbi.nlm.nih.gov/pubmed/29884623
%X N6-methylated adenine (m6A) is the most frequent posttranscriptional modification in eukaryotic mRNA. Turnover of RNA generates N6-methylated AMP (N6-mAMP), which has an unclear metabolic fate. We show that Arabidopsis thaliana and human cells require an N6-mAMP deaminase (ADAL, renamed MAPDA) to catabolize N6-mAMP to inosine monophosphate (IMP) in vivo by hydrolytically removing the aminomethyl group. A phylogenetic, structural, and biochemical analysis revealed that many fungi partially or fully lack MAPDA, which coincides with a minor role of N6A-RNA methylation in these organisms. MAPDA likely protects RNA from m6A mis-incorporation. This is required because eukaryotic RNA polymerase can use N6-mATP as a substrate. Upon abrogation of MAPDA, root growth is slightly reduced, and the N6-methyladenosine, N6-mAMP, and N6-mATP concentrations are increased in Arabidopsis. Although this will potentially lead to m6A mis-incorporation into RNA, we show that the frequency is too low to be reliably detected in vivo. Since N6-mAMP was several fold more abundant than N6-mATP in MAPDA mutants, we speculate that additional molecular filters suppress the generation of N6-mATP. Enzyme kinetic data indicate that adenylate kinases represent such filters being highly selective for AMP versus N6-mAMP phosphorylation. We conclude that a multilayer molecular protection system is in place preventing N6-mAMP accumulation and salvage.
@article{Chen2018,
abstract = {N6-methylated adenine (m6A) is the most frequent posttranscriptional modification in eukaryotic mRNA. Turnover of RNA generates N6-methylated AMP (N6-mAMP), which has an unclear metabolic fate. We show that Arabidopsis thaliana and human cells require an N6-mAMP deaminase (ADAL, renamed MAPDA) to catabolize N6-mAMP to inosine monophosphate (IMP) in vivo by hydrolytically removing the aminomethyl group. A phylogenetic, structural, and biochemical analysis revealed that many fungi partially or fully lack MAPDA, which coincides with a minor role of N6A-RNA methylation in these organisms. MAPDA likely protects RNA from m6A mis-incorporation. This is required because eukaryotic RNA polymerase can use N6-mATP as a substrate. Upon abrogation of MAPDA, root growth is slightly reduced, and the N6-methyladenosine, N6-mAMP, and N6-mATP concentrations are increased in Arabidopsis. Although this will potentially lead to m6A mis-incorporation into RNA, we show that the frequency is too low to be reliably detected in vivo. Since N6-mAMP was several fold more abundant than N6-mATP in MAPDA mutants, we speculate that additional molecular filters suppress the generation of N6-mATP. Enzyme kinetic data indicate that adenylate kinases represent such filters being highly selective for AMP versus N6-mAMP phosphorylation. We conclude that a multilayer molecular protection system is in place preventing N6-mAMP accumulation and salvage.},
added-at = {2018-06-22T14:24:50.000+0200},
author = {Chen, Mingjia and Urs, Mounashree J and S{\'{a}}nchez-Gonz{\'{a}}lez, Ismael and Olayioye, Monilola A and Herde, Marco and Witte, Claus-Peter},
biburl = {https://puma.ub.uni-stuttgart.de/bibtex/2c9a6febd09320036938e64464f93610d/cristiano},
doi = {10.1105/tpc.18.00236},
interhash = {49183718986dd87c31d5021d95c627a4},
intrahash = {c9a6febd09320036938e64464f93610d},
issn = {1532-298X},
journal = {The Plant cell},
keywords = {2018 izi olayioye},
month = jun,
pages = {tpc.00236.2018},
pmid = {29884623},
publisher = {American Society of Plant Biologists},
timestamp = {2019-01-17T12:20:24.000+0100},
title = {{m6A RNA Degradation Products are Catabolized by an Evolutionarily Conserved N6-methyl-AMP Deaminase in Plant and Mammalian Cells.}},
url = {http://www.ncbi.nlm.nih.gov/pubmed/29884623},
year = 2018
}
