Dioxygenase that acts as on nucleic acids, such as DNA and tRNA. Requires molecular oxygen, alpha-ketoglutarate and iron. Mainly acts as a tRNA demethylase by removing N1-methyladenine from various tRNAs, with a preference for N1-methyladenine at position 58 present on a stem loop structure of tRNAs. Acts as a regulator of translation initiation and elongation in response to glucose deprivation: regulates both translation initiation, by mediating demethylation of tRNA (Met), and translation elongation, N1-methyladenine-containing tRNAs being preferentially recruited to polysomes to promote translation elongation. In mitochondrion, specifically interacts with mt-tRNA (Met) and mediates oxidation of mt-tRNA (Met) methylated at cytosine to form 5-formylcytosine (f5c) at this position. mt-tRNA (Met) containing the f5c modification at the wobble position enables recognition of the AUA codon in addition to the AUG codon, expanding codon recognition in mitochondrial translation. N6-methyladenosine (m6A) DNA is present at some L1 elements in embryonic stem cells and probably promotes their silencing . Demethylates mRNAs containing N3-methylcytidine modification. Also able to repair alkylated single-stranded DNA by oxidative demethylation, but with low activity. Also has DNA lyase activity and introduces double-stranded breaks at abasic sites: cleaves both single-stranded DNA and double-stranded DNA at abasic sites, with the greatest activity towards double-stranded DNA with two abasic sites. DNA lyase activity is not required during base excision repair and class switch recombination of the immunoglobulin heavy chain during B lymphocyte activation. May play a role in placental trophoblast lineage differentiation.