High impact information on TFB1M

• Our results show that TFB1M is a nonredundant dimethyltransferase in mammalian mitochondria [1]
• Here we report that mitochondrial transcription factors B1 (TFB1M) and B2 (TFB2M) are necessary for basal transcription of mammalian mitochondrial DNA (mtDNA) [2].
• Remarkably, h-mtTFB and its fungal homologs are related in primary sequence to a superfamily of N6 adenine RNA methyltransferases [3].
• This observation, coupled with the ability of recombinant h-mtTFB to bind S-adenosylmethionine in vitro, suggests that a structural, and perhaps functional, relationship exists between this class of transcription factors and this family of RNA modification enzymes and that h-mtTFB may perform dual functions during mitochondrial gene expression [3].
• Finally, phylogenetic analyses of this family of proteins strongly suggest that the presence of two mtTFB homologues in metazoans is the result of a gene duplication event that occurred early in eukaryotic evolution prior to the divergence of fungi and metazoans [4].
• Linkage disequilibrium by the Transmission Disequilibrium Test at D6S1577, a microsatellite adjacent to TFB1M, showed preferential non-transmission of an allele to affected individuals with chi2 = 8.76; P = 0.003 [5].

Biological context of TFB1M

• Human mitochondrial transcription factor B1 (TFB1M) has been proposed as a candidate for being such a modifier, since it methylates adenine residues in the adjacent loop of the A1555G mutation in the 12S rRNA gene [5].
• These regions display conserved linkage synteny with human Chr 6 and Chr 1, where TFB1M and TFB2M map [6].

Other interactions of TFB1M

• The relative ease with which mtTFA can be purified (Fisher et al. 1991) suggests that, where present, it should be facile to detect. mtTFB may represent a eubacterial sigma factor adapted for interaction with the mitochondrial RNA polymerase.(ABSTRACT TRUNCATED AT 400 WORDS)[7]

References