S-adenosyl-L-methionine-dependent methyltransferase which specifically dimethylates mitochondrial 12S rRNA at the conserved stem loop. Also required for basal transcription of mitochondrial DNA, probably via its interaction with POLRMT and TFAM. Stimulates transcription independently of the methyltransferase activity.
Note=Variations in TFB1M may influence the clinical expression of aminoglycoside-induced deafness caused by the A1555G mutation in the mitochondrial 12S rRNA.
Belongs to the methyltransferase superfamily. rRNA adenine N(6)-methyltransferase family. KsgA subfamily.