Table 2 |.
Enzymes that regulate adenine methylation
| Enzymes | Substrates | Prevalence | Refs. |
|---|---|---|---|
| Methyltransferases | |||
| METTL3–METTL14 | m6A mRNAs | 25% of mRNAs3,4 | 6,169 |
| IME4 | m6A mRNAs | NA | 170 |
| METTL16 | m6A snRNA, mRNAs, and other ncRNAs | NA | 65,66,171 |
| PCIF1 | m6Am mRNA cap | 30% of mRNAs | 172–175 |
| CMTR1 | Am mRNA | NA | 176 |
| FBL | Am rRNA | 40–100%56 | 177–180 |
| TRMT61A | m1A58 tRNA | Most tRNAs181 | 182 |
| TRMT61B | m1A nuclear encoded tRNA | NA | 183 |
| TRMT10B | m1A nuclear encoded tRNA | NA | 184 |
| TRMT10C | m1A mitochondrial mRNA | NA | 185 |
| DIM1 | m6,2A 18S rRNA A1850, 1851 | NA | 186–188 |
| METTL4 | m6Am snRNA | NA | 189,190 |
| Demethylases | |||
| FTO | m6A, m6Am RNA | NA | 10,126 |
| ALKBH5 | m6A RNA | NA | 9 |
| ALKBH1 | m1A, m5C and hm5C tRNA | NA | 191,192 |
| ALKBH3 | m1A RNA and DNA | NA | 193 |
| Binding proteins | |||
| YTHDC1 | m6A mRNAs | NA | 194,195 |
| YTHDC2 | m6A mRNAs | NA | 100,101 |
| YTHDF1 | m6A mRNAs | NA | 38,196 |
| YTHDF2 | m6A mRNAs | NA | 4,41 |
| YTHDF3 | m6A mRNAs | NA | 4 |
| ELAVL1 | m6A mRNAs | NA | 4 |
| eIF3 | m6A mRNAs | NA | 37 |
| HNRNPC/G | m6A mRNAs | NA | 26,197 |
| HNRNPA2B1 | m6A mRNAs | NA | 44 |
| IGF2BP1–3 | m6A mRNAs | NA | 33 |
| FMRP | m6A mRNAs | NA | 34 |
Am, 2′-O-methyladenosine; eIF3, eukaryotic translation initiation factor 3; FMRP, fragile X mental retardation protein; hm5C, 5-hydroxymethylcytosine; HNRNP, heterogeneous nuclear ribonucleoprotein; IGF2BP, insulin-like growth factor 2 binding protein; m1A, N1-methyladenosine; m5C, C5-cytosine methylation; m6A, N6-methyladenosine; m6,2A, N6,N6-dimethyladenosine; m6Am, N 6,2′-O-dimethyladenosine; NA, not available; ncRNA, non-coding RNA; rRNA, ribosomal RNA; snRNA, small nuclear RNA.