m1A Post‐Transcriptional Modification in tRNAs

Abstract

To date, about 90 post-transcriptional modifications have been reported in tRNA expanding their chemical and functional diversity. Methylation is the most frequent post-transcriptional tRNA modification that can occur on almost all nitrogen sites of the nucleobases, on the C5 atom of pyrimidines, on the C2 and C8 atoms of adenosine and, additionally, on the oxygen of the ribose 2′-OH. The methylation on the N1 atom of adenosine to form 1-methyladenosine (m1A) has been identified at nucleotide position 9, 14, 22, 57, and 58 in different tRNAs. In some cases, these modifications have been shown to increase tRNA structural stability and induce correct tRNA folding. This review provides an overview of the currently known m1A modifications, the different m1A modification sites, the biological role of each modification, and the enzyme responsible for each methylation in different species. The review further describes, in detail, two enzyme families responsible for formation of m1A at nucleotide position 9 and 58 in tRNA with a focus on the tRNA binding, m1A mechanism, protein domain organisation and overall structures.

The stress specific impact of ALKBH1 on tRNA cleavage and tiRNA generation

“…1-methyladenosine (m 1 A) modifications in tRNA occur at positions 9, 14, 22, 57 and 58 in cytosolic tRNA species and at 9 and 58 positions in mitochondrial tRNA species 12 . While they are common in tRNA, m 1 A modifications are comparatively rare in mRNA 13,14 .…”

Active role of free RNA during the early phase of proteostasis stress

“…Next, we analyzed the TRMT6/61A complex, one of the top enrichments among the RNA interactors (Table S2, Figure 4C and Figure S4D). TRMT6/61A has been known as a tRNA methyltransferase able to methylate adenine 58 at N1 in tRNAs 18 . Recently, m 1 A was identified also in eukaryotic mRNAs which implicated the modification in posttranscriptional regulation of gene expression 19,20 .…”

Antibody cross-reactivity accounts for widespread appearance of m1A in 5’ UTRs

“…Notably, this modified adenosine is found at a position corresponding to position 58 in the Tloop of tRNAs ( Fig. 1d), a conserved position of m 1 A in tRNAs 15 . This site may be a m 1 A formed by T-loop-specific m 1 A-synthesizing enzymes 15 .…”

“…1d), a conserved position of m 1 A in tRNAs 15 . This site may be a m 1 A formed by T-loop-specific m 1 A-synthesizing enzymes 15 .…”