The mitochondrial transcription termination factor mTERF modulates replication pausing in human mitochondrial DNA.

TitleThe mitochondrial transcription termination factor mTERF modulates replication pausing in human mitochondrial DNA.
Publication TypeJournal Article
Year of Publication2007
AuthorsHyvärinen, AK, Pohjoismäki, JLO, Reyes, A, Wanrooij, S, Yasukawa, T, Karhunen, PJ, Spelbrink, JN, Holt, IJ, Jacobs, HT
JournalNucleic Acids Res
Volume35
Issue19
Pagination6458-74
Date Published2007
ISSN1362-4962
KeywordsBasic-Leucine Zipper Transcription Factors, Binding Sites, Cell Line, DNA Replication, DNA, Mitochondrial, Genome, Mitochondrial, Humans, Mitochondrial Proteins, NADH Dehydrogenase, RNA Interference, RNA, Transfer, Leu
Abstract

The mammalian mitochondrial transcription termination factor mTERF binds with high affinity to a site within the tRNA(Leu(UUR)) gene and regulates the amount of read through transcription from the ribosomal DNA into the remaining genes of the major coding strand of mitochondrial DNA (mtDNA). Electrophoretic mobility shift assays (EMSA) and SELEX, using mitochondrial protein extracts from cells induced to overexpress mTERF, revealed novel, weaker mTERF-binding sites, clustered in several regions of mtDNA, notably in the major non-coding region (NCR). Such binding in vivo was supported by mtDNA immunoprecipitation. Two-dimensional neutral agarose gel electrophoresis (2DNAGE) and 5' end mapping by ligation-mediated PCR (LM-PCR) identified the region of the canonical mTERF-binding site as a replication pause site. The strength of pausing was modulated by the expression level of mTERF. mTERF overexpression also affected replication pausing in other regions of the genome in which mTERF binding was found. These results indicate a role for TERF in mtDNA replication, in addition to its role in transcription. We suggest that mTERF could provide a system for coordinating the passage of replication and transcription complexes, analogous with replication pause-region binding proteins in other systems, whose main role is to safeguard the integrity of the genome whilst facilitating its efficient expression.

DOI10.1093/nar/gkm676
Alternate JournalNucleic Acids Res.
Citation Key10.1093/nar/gkm676
PubMed ID17884915
PubMed Central IDPMC2095818
Grant ListMC_U105663140 / / Medical Research Council / United Kingdom