Homologs of mitochondrial transcription factor B, sparsely distributed within the eukaryotic radiation, are likely derived from the dimethyladenosine methyltransferase of the mitochondrial endosymbiont.
Mitochondrial transcription factor B (mtTFB), an essential component in regulating the expression of mitochondrial DNA-encoded genes in both yeast and humans, is a dimethyladenosine methyltransferase (DMT) that has acquired a secondary role in mitochondrial transcription. So far, mtTFB has only been well studied in Opisthokonta (metazoan animals and fungi). Here we investigate the phylogenetic distribution of mtTFB homologs throughout the domain Eucarya, documenting the first examples of this protein outside of the opisthokonts. Surprisingly, we identified putative mtTFB homologs only in amoebozoan protists and trypanosomatids. Phylogenetic analysis together with conservation of intron positions in amoebozoan and human genes supports the grouping of the putative mtTFB homologs as a distinct clade. Phylogenetic analysis further demonstrates that the mtTFB is most likely derived from the DMT of the mitochondrial endosymbiont.
Program in Evolutionary Biology, Canadian Institute for Advanced Research, Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Canada.
Timothy E
TE
Shutt
Michael W
MW
Gray
D048248:Acanthamoeba castellanii / Q000235:genetics; D020561:Alphaproteobacteria / Q000235:genetics; D000595:Amino Acid Sequence; D000818:Animals; D004268:DNA-Binding Proteins / Q000235:genetics; D004023:Dictyostelium / Q000235:genetics; D056890:Eukaryota / Q000235:genetics*; D005057:Eukaryotic Cells; D019143:Evolution, Molecular; D006249:Hartmannella / Q000235:genetics; D006801:Humans; D007438:Introns; D008928:Mitochondria / Q000235:genetics*; D024101:Mitochondrial Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D010802:Phylogeny; D012689:Sequence Homology, Nucleic Acid; D013559:Symbiosis; D014157:Transcription Factors / Q000235:genetics*
D004268:DNA-Binding Proteins; D024101:Mitochondrial Proteins; C499632:TFB1M protein, human; D014157:Transcription Factors