A unique mitochondrial transcription factor B protein in Dictyostelium discoideum.
Unlike their bacteriophage homologs, mitochondrial RNA polymerases require the assistance of transcription factors in order to transcribe mitochondrial DNA efficiently. The transcription factor A family has been shown to be important for transcription of the human mitochondrial DNA, with some of its regulatory activity located in its extended C-terminal tail. The mitochondrial transcription factor B family often has functions not only in transcription, but also in mitochondrial rRNA modification, a hallmark of its α-proteobacterial origin. We have identified and characterised a mitochondrial transcription factor B homolog in the soil dwelling cellular slime mould Dictyostelium discoideum, an organism widely established as a model for studying eukaryotic cell biology. Using in bacterio functional assays, we demonstrate that the mitochondrial transcription factor B homolog not only functions as a mitochondrial transcription factor, but that it also has a role in rRNA methylation. Additionally, we show that the transcriptional activation properties of the D. discoideum protein are located in its extended C-terminal tail, a feature not seen before in the mitochondrial transcription factor B family, but reminiscent of the human mitochondrial transcription factor A. This report contributes to our current understanding of the complexities of mitochondrial transcription, and its evolution in eukaryotes.
Department of Microbiology, La Trobe University, Melbourne, Victoria, Australia.
Sam
S
Manna
Phuong
P
Le
Christian
C
Barth
D000595:Amino Acid Sequence; D004268:DNA-Binding Proteins / Q000032:analysis / Q000378:metabolism*; D004023:Dictyostelium / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008745:Methylation; D008928:Mitochondria / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000032:analysis / Q000378:metabolism*; D008969:Molecular Sequence Data; D015800:Protozoan Proteins / Q000032:analysis / Q000378:metabolism*; D012335:RNA, Ribosomal / Q000378:metabolism; D016415:Sequence Alignment; D014157:Transcription Factors / Q000032:analysis / Q000378:metabolism*; D015533:Transcriptional Activation
D004268:DNA-Binding Proteins; D024101:Mitochondrial Proteins; D015800:Protozoan Proteins; D012335:RNA, Ribosomal; C499632:TFB1M protein, human; D014157:Transcription Factors