Dimethyladenosine transferase 1, mitochondrial is an enzyme that in humans is encoded by the TFB1M gene.

The protein encoded by this gene is a dimethyltransferase that methylates the conserved stem loop of mitochondrial 12S rRNA. The encoded protein also is part of the basal mitochondrial transcription complex and is necessary for mitochondrial gene expression. The methylation and transcriptional activities of this protein are independent of one another. Variations in this gene may influence the severity of aminoglycoside-induced deafness (AID).[provided by RefSeq, Aug 2010]. Sequence Note: This RefSeq record was created from transcript and genomic sequence data to make the sequence consistent with the reference genome assembly. The genomic coordinates used for the transcript record were based on transcript alignments. Publication Note: This RefSeq record includes a subset of the publications that are available for this gene. Please see the Gene record to access additional publications.
Function: 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.