DNA-protein interactions in the<i>Drosophila virilis</i>mitochondrial chromosome

Pardue, Mary Lou; Fostel, Jennifer; Cech, Thomas R.

doi:10.1093/nar/12.4.1991

Cited by 14 publications

(5 citation statements)

References 22 publications

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“…Precise mapping of both the 59 and 39 ends of RNA may provide important clues for understanding the function of the T-stretch and the replication initiation process. Although studies examining the protein-DNA interaction in the A 1 T-rich region are essential for understanding the replication initiation process of Drosophila mtDNA, only a few studies have been performed (Potter et al 1980;Pardue et al 1984). The identification of potentially functional sequences, such as the T-stretch, may provide useful information for analyzing the DNA-protein interaction of the Drosophila A 1 T-rich region in future studies.…”

Section: Discussionmentioning

confidence: 99%

Replication Origin of Mitochondrial DNA in Insects

2005

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The precise position of the replication origin (O R ) of mtDNA was determined for insect species belonging to four different orders (four species of Drosophila, Bombyx mori, Triborium castaneum, and Locusta migratoria, which belong to Diptera, Lepidoptera, Coleoptera, and Orthoptera, respectively). Since the free 59 ends of the DNA strands of mtDNA are interpreted as the O R , their positions were mapped at 1-nucleotide resolution within the A 1 T-rich region by using the ligation-mediated PCR method. In all species examined, the free 59 ends were found within a very narrow range of several nucleotides in the A 1 T-rich region. For four species of Drosophila, B. mori, and T. castaneum, which belong to holometabolous insects, although the O R 's were located at different positions, they were located immediately downstream of a series of thymine nucleotides, the so-called T-stretch. These results strongly indicate that the T-stretch is involved in the recognition of the O R of mtDNA at least among holometabolous insects. For L. migratoria (hemimetabolous insect), on the other hand, none of the long stretches of T's was found in the upstream portion of the O R , suggesting that the regulatory sequences involved in the replication initiation process have changed through insect evolution.

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Section: Discussionmentioning

confidence: 99%

Replication Origin of Mitochondrial DNA in Insects

2005

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“…Different groups, working mainly on animal mitochondria, have confirmed this observation, but no evidence has been produced concerning the functional nature of these mitochondrial nucleoids. Psoralen cross-linked protein-DNA complexes in HeLa and Drosophila mitochondria [ 10,25] suggest that animal mtDNA association with the membrane involves a region associated with the replication origin (the D-loop region for HeLa cells). Specific proteins having strong affinity for single-stranded mtDNA, and hence the D-loop region, have been purified from Xenopus laevis ovary and rat liver [21,31] but their functions remain unknown.…”

Section: Discussionmentioning

confidence: 99%

“…This system places the enzyme activities that we have characterized previously in the solubilized extract in a more physiological context and emphasizes the importance of the mitochondrial membrane as an element of the DNA replication machinery, as shown for the bacterial membrane [15,32]. Finally, we attempted to determine whether wheat mtDNA is anchored to the mitochondrial membrane through specific DNA regions, which could be related to wheat mtDNA replication origin(s), as in bacteria [15,32], and as has been suggested for animal mtDNA [10,25]. A preliminary account of this work has been presented before [13].…”

Section: Introductionmentioning

confidence: 91%

Isolation from wheat mitochondria of a membrane-associated high molecular weight complex involved in DNA synthesis

et al. 1991

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A high molecular weight mitochondrial DNA (mtDNA) replication complex, associated with the mitochondrial membrane, was isolated by sucrose gradient centrifugation from purified wheat embryo mitochondria. This complex comprised the mtDNA as well as enzyme activities involved in the replication and transcription of the organelle genome, such as DNA polymerase, RNA polymerase and topoisomerase type I. The isolated complex is active in mtDNA and mtRNA synthesis in vitro. Electron microscopy and lipid analysis confirmed the membrane origin of this complex. Enzyme activities are resistant to physiological ionic strengths, 0.1-0.2 M KC1, while the membrane-mtDNA association is resistant up to 1 M KC1. DNase treatment of the complex released the DNA polymerase activity while protease treatment solubilized mtDNA, suggesting the direct interaction of mtDNA with membrane protein(s). The use of a novel approach to detect mtDNA fragments specifically retained by the mitochondrial membranes after Sal I digestion of the complex suggests that specific mtDNA sequences anchor mtDNA to mitochondrial membranes.

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“…There are several reports that mtDNA in higher eukaryotes is somewhat naked except for the D-loop region (2,7,29,31), while the mtDNA of Xenopus laevis is reported to be packaged into regular beaded structures (3). These conflicting results on whether animal mtDNA takes on a higher nucleosome-or chromatin-like structure (mitochondrial nucleoid or mitochromatin/mitochondrial chromosome) are not fully resolved.…”

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confidence: 99%

Architectural Role of Mitochondrial Transcription Factor A in Maintenance of Human Mitochondrial DNA

Kanki

Ohgaki

Gaspari

et al. 2004

Molecular and Cellular Biology

273

224

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Mitochondrial transcription factor A (TFAM), a transcription factor for mitochondrial DNA (mtDNA) that also possesses the property of nonspecific DNA binding, is essential for maintenance of mtDNA. To clarify the role of TFAM, we repressed the expression of endogenous TFAM in HeLa cells by RNA interference. The amount of TFAM decreased maximally to about 15% of the normal level at day 3 after RNA interference and then recovered gradually. The amount of mtDNA changed closely in parallel with the daily change in TFAM while in organello transcription of mtDNA at day 3 was maintained at about 50% of the normal level. TFAM lacking its C-terminal 25 amino acids (TFAM-⌬C) marginally activated transcription in vitro. When TFAM-⌬C was expressed at levels comparable to those of endogenous TFAM in HeLa cells, mtDNA increased twofold, suggesting that TFAM-⌬C is as competent in maintaining mtDNA as endogenous TFAM under these conditions. The in organello transcription of TFAM-⌬C-expressing cells was no more than that in the control. Thus, the mtDNA amount is finely correlated with the amount of TFAM but not with the transcription level. We discuss an architectural role for TFAM in the maintenance of mtDNA in addition to its role in transcription activation.

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DNA-protein interactions in theDrosophila virilismitochondrial chromosome

Cited by 14 publications

References 22 publications

Replication Origin of Mitochondrial DNA in Insects

Replication Origin of Mitochondrial DNA in Insects

Isolation from wheat mitochondria of a membrane-associated high molecular weight complex involved in DNA synthesis

Architectural Role of Mitochondrial Transcription Factor A in Maintenance of Human Mitochondrial DNA

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