| Abstract: |
The mammalian MTERF family of proteins has four members, named MTERF1 to MTERF4, which were identified in homology searches using the mitochondrial transcription termination factor, mTERF (here denoted MTERF1) as query. MTERF1 and MTERF3 are known to participate in the control of mitochondrial DNA transcription, but the function of the other two proteins is not known. We here investigate the structure and function of MTERF2. Protein import experiments using isolated organelles confirm that MTERF2 is a mitochondrial protein. Edman degradation of MTERF2 isolated from stably transfected HeLa cells demonstrates that mature MTERF2 lacks a targeting peptide (amino acids 1-35) present in the precursor form of the protein. MTERF2 is a monomer in isolation and displays a non sequence-specific DNA-binding activity. In vivo quantification experiments demonstrate that MTERF2 is relatively abundant, with one monomer present per ∼ 265 bp of mtDNA. In comparison, the mtDNA packaging factor TFAM is present at a ratio of one molecule per ∼ 10-12 bp of mtDNA. Using formaldehyde cross-linking we demonstrate that MTERF2 is present in nucleoids, and therefore must be located in close proximity to mtDNA. Taken together, our work provides a basic biochemical characterization of MTERF2, paving the way for future functional studies. © 2009 Elsevier B.V. All rights reserved. |
| Keywords: |
controlled study; unclassified drug; human cell; dna replication; protein localization; protein analysis; mammalia; animals; mice; transcription factor; in vivo study; hela cell; structure activity relation; cloning, molecular; amino acid sequence; molecular sequence data; quantitative analysis; nucleotide sequence; transcription; dna primers; sequence homology; protein family; mammals; mitochondrial membrane; basic-leucine zipper transcription factors; dna, mitochondrial; mitochondria; mitochondrion; protein cross linking; complementary dna; chromatography, gel; mterf; nucleoid; termination; mitochondrial dna; mitochondrial transcription termination factor; mterf1 protein; mterf2 protein; protein isolation; dna, complementary; mitochondria, liver
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