Transcription Factor B1, Mitochondrial (TFB1M)

The transcription of genes from mitochondrial DNA requires a mitochondrial RNA polymerase and a DNA-binding transcription factor. TFB1M is a part of this transcription complex.The primary function of TFB2M is mtDNA transcription and maintenance, which is independent of its rRNA methyltransferase activity, while that of TFB1M is mitochondrial 12S rRNA methylation needed for normal mitochondrial translation, metabolism, and cell growth. Overexpression of TFB1M caused 12S rRNA hypermethylation, aberrant mitochondrial biogenesis, and increased sorbitol-induced cell death. These phenotypes were recapitulated in cells harboring the pathogenic 1555A-G mtDNA mutation, implicating a deleterious rRNA methylation-dependent retrograde signal in maternally inherited deafness pathology.