Catalytic subunit of a heterodimer with TRMT112, which specifically methylates the 6th position of adenine in position 1832 of 18S rRNA (PubMed:32783360, PubMed:35033535). N6-methylation of adenine(1832) in 18S rRNA resides in the decoding center of 18S rRNA and is required for translation and embryonic stem cells (ESCs) pluripotency and differentiation (PubMed:32783360, PubMed:32217665). adenosine(1832) in 18S rRNA + S-adenosyl-L-methionine = H(+) + N(6)-methyladenosine(1832) in 18S rRNA + S-adenosyl-L-homocysteine rRNA N6-adenosine-methyltransferase activity is inhibited by zinc. Heterodimer; heterodimerizes with TRMT112. Ubiquitously expressed in brain. Mice were born at non-Mendelian rates and develop morphological, such as craniofacial abnormalities, snout deviation due to altered nasal bone development and incomplete fusion of the frontal bone suture (PubMed:32217665). Mice display reduced body size and evidence of metabolic defects (PubMed:35033535). Mice also show behavioral abnormalities (PubMed:32217665). Deletion in embryonic stem cells (ESCs) results in a decrease in global translation rate, spontaneous loss of pluripotency and compromised differentiation potential (PubMed:32783360, PubMed:32217665). Cells show abolished level of N6-methylation of adenine(1832) in 18S rRNA (PubMed:35033535). Belongs to the methyltransferase superfamily. PrmA family.