text: mRNA methylation is important throughout the entire life-cycle of the mRNA, starting with the alternative polyadenylation (APA) of some transcripts. mA sites are often located in the last exon, mostly in the 3’ untranslated region (3-UTR). The presence of mA in the 3’-UTR promotes the use of the proximal APA site, resulting in a shorter 3’-UTR. Splicing of the pre-mRNA transcripts may be influenced by mA, although this effect can vary across different biological systems. Furthermore, nuclear export of mature mRNAs depends on mA; when the mA "writers" are inhibited, there is a delay in the export of the mature mRNAs. However, normal nuclear export does not solely depend on mA, other mRNA marks such as 5-methylcytosine (mC) are also involved.
  The mA mark has a notable effect on translational dynamics. There are various ways in which mA is involved in translational efficiency. For instance, this modification modulates multiple steps in the process of tRNA incorporation. On the one hand, it slows down GTP hydrolysis by EF-Tu by 12-fold and the peptidyl transfer reaction by two-fold. It also causes a 1.5-fold increase in the amount of GTP hydrolyzed per peptidyl transfer, which indicates that a lot of proofreading is required. Moreover, because it is just a modified adenosine base, mA base-pairs with uridine during decoding. However, the adenosine's methylation hinders tRNA accommodation and translation elongation. When a mA-modified codon interacts with its cognate tRNA (the tRNA with the anticodon that is complementary to a particular codon), it acts more like a near-cognate codon interaction instead of the cognate codon interaction. This can be seen in the delay in the tRNA accommodation, which is dependent upon both the position of the mA in the mRNA codons and on how accurate the translation is. Overall, this mA modification leads to a kinetic loss of a factor of 18. To summarize, translation-elongation dynamics are slower for codons with mA and different locations of these modified nucleotides in the mRNA codons affect decoding dynamics in different ways.
  However, this mark can also increase translational efficiency. The mA "reader" YTHDF1 induces the association of the modified mRNA with the ribosome. Furthermore, it also recruits the translation initiation factor eIF3 to the mRNA independently of METTL3. Additionally, eIF3 also acts as a "reader" of a mA located in the 5’-UTR of the mRNA, which results in recruitment of the 40S translational preinitiation complex. This interaction is involved in cap-independent translation, which happens during the cellular response to heat shock stress.
  mA methylation also modulates mRNA stability.  The "reader" YTHDF2 binds to mA-containing mRNAs and decreases their stability by recruiting them to P-bodies, in a process called methylation-dependent mRNA decay. This process is needed to rapidly degrade pluripotency transcription factor transcripts, to enable the commitment of a pluripotent stem cell to a specific cell lineage. Reduced levels of mA in mice embryos lead to embryonic lethality during the early stages of development.