A 20 × 10<sup>3</sup>‐base mosaic gene identified on the mitochondrial chromosome of <i>Podospora anserina</i>

Jamet‐Vierny, Còrinne; Begel, Odile; Belcour, Léon

doi:10.1111/j.1432-1033.1984.tb08385.x

Cited by 26 publications

(3 citation statements)

References 31 publications

(34 reference statements)

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“…(i) Out of 15 mutants escaping senescence, 11 were found to be mitochondrial mutants and five of them to carry a deletion in region a. This region, the most frequently and accurately amplified in senescent cultures, corresponds to the first intron of the 20-kb gene coding for subunit one of cytochrome oxidase (Osiewacz and Esser, 1984;Jamet-Vierny et al, 1984;Cummings et al, 1985).…”

Section: Discussionmentioning

confidence: 99%

“…A few non-overlapping regions (a, 3, -y, E) of the mitochondrial chromosome can generate SEN-DNA molecules as the mycelium becomes senescent (Belcour et al, 1981;Wright et al, 1982a;Koll et al, 1985;Cummings et al, 1985). Among them, the a region seems to have a special status since: (i) it is the most frequently amplified in senescent cultures; (ii) it always gives rise to the same unit of repetition (2539 bp long), in contrast to the other regions (Belcour et al, 1981;Koll et al, 1985); (iii) it corresponds exactly to an intron (Osiewacz and Esser, 1984) of the cytochrome oxidase subunit 1 gene (Jamet-Vierny et al, 1984;Kuck et al, 1985;Cummings et al, 1985).…”

Section: Introductionmentioning

confidence: 99%

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Variable DNA splicing sites of a mitochondrial intron: relationship to the senescence process in Podospora

Belcour

Vierny

1986

The EMBO Journal

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The unavoidable phenomenon of senescence in Podospora was previously shown to be correlated with the presence of a senescence‐specific DNA originating from amplification of some regions of the mitochondrial chromosome. The most frequently amplified region (α) corresponds to the first intron of the gene coding for subunit one of cytochrome oxidase. Eleven long‐lived mitochondrial mutants were isolated. Here we report sequencing experiments that show that three of them are deleted for most of intron α and for a few base pairs belonging to the upstream adjacent exon. We also report an analysis of the residual mitochondrial DNA associated with amplification of senescence‐specific DNA α which allows us to identify, in senescent cultures, mitochondrial chromosomes lacking sequence α. These results taken together suggest that excision of intron α from the mitochondrial DNA occurs systematically during the aging process in Podospora. They furthermore provide the first example of inaccurate intron excision at the DNA level.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Variable DNA splicing sites of a mitochondrial intron: relationship to the senescence process in Podospora

Belcour

Vierny

1986

The EMBO Journal

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“…Localization of genes was carried out by cross hybridization at reduced stringency with probes from coding regions of S. cerevisiae mtDNA. This strategy has proven successful based on DNA sequencing in a number of other organisms (Lang et al 1983;Dujon 1983;Scazzochio et al 1983), although exceptions have been reported (Johnson et al 1982;Benne et al 1983;Wright et al 1982;Jamet-Vierny et al 1984). In the present case, the approach is rationalized by the finding of a single hybridizing region on each mtDNA with eight of the nine probes employed.…”

Section: Discussionmentioning

confidence: 91%

Analysis of the mitochondrial and nuclear genomes of two basidiomycetes, Coprinus cinereus and Coprinus stercorarius

et al. 1986

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The mitochondrial and nuclear genomes of Coprinus stercorarius and C. cinereus were compared to assess their evolutionary relatedness and to characterize at the molecular level changes that have occurred since they diverged from a common ancestor. The mitochondrial genome of C. stercorarius (91.1 kb) is approximately twice as large as that of C. cinereus (43.3 kb). The pattern of restriction enzyme recognition sites shows both genomes to be circular, but reveals no clear homologies; furthermore, the order of structural genes is different in each species. The C. stercorarius mitochondrial genome contains a region homologous to a probe derived from the yeast mitochondrial var1 gene, whereas its nuclear genome does not. By contrast, the C. cinereus nuclear, but not mitochondrial, genome contains a region homologous to the var1 probe. Only a small fraction of either the nuclear or mitochondrial genomes, perhaps corresponding to the coding sequences, is capable of forming duplexes in interspecies solution reassociations, as measured by binding to hydroxylapatite. Those sequences capable of reassociating were found to have approximately 15% divergence for the mitochondrial genomes and 7%-15% divergence for the nuclear genomes, depending on the conditions of reassociation.

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Reverse transcriptase activity of an intron encoded polypeptide.

et al. 1994

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A number of group II introns from eukaryotic organelies and prokaryotes contain open reading frames for polypeptides with homology to retroviral reverse transcriptases (RTs). We have used the yeast transposon (Ty) system to express ORFs for RTs from eukaryotic organelies. This includes the mitochondrial coxI intron il from the fungus Podospora anserina, the plastid petD intron from the alga Scenedesmus obliquus and the mitochondrial RTh gene from the alga Chlamydomonas reinhardtii. The ORFs were fused with the TYA ORF from the yeast retrotransposon Ty to produce virus-like particles in the recipient strains with detectable amounts of the RT-like polypeptides. Analysis of the heterologous gene products revealed biochemical evidence that the P.anserina intron encodes an RNA-directed DNA polymerase with properties typically found for RTs of viral or retrotransposable origin. In vitro assays showed that the intron encoded RT is sensitive to RT inhibitors such as N-ethylmaleimide and dideoxythymidine triphosphate but is insensitive against the DNA polymerase inhibitor aphidicolin. The direct biochemical evidence provided here supports the idea that intron encoded RTs are involved in intron transposition events.

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A 20 × 10³‐base mosaic gene identified on the mitochondrial chromosome of Podospora anserina

Cited by 26 publications

References 31 publications

Variable DNA splicing sites of a mitochondrial intron: relationship to the senescence process in Podospora

Variable DNA splicing sites of a mitochondrial intron: relationship to the senescence process in Podospora

Analysis of the mitochondrial and nuclear genomes of two basidiomycetes, Coprinus cinereus and Coprinus stercorarius

Reverse transcriptase activity of an intron encoded polypeptide.

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A 20 × 103‐base mosaic gene identified on the mitochondrial chromosome of Podospora anserina

Cited by 26 publications

References 31 publications

Variable DNA splicing sites of a mitochondrial intron: relationship to the senescence process in Podospora

Variable DNA splicing sites of a mitochondrial intron: relationship to the senescence process in Podospora

Analysis of the mitochondrial and nuclear genomes of two basidiomycetes, Coprinus cinereus and Coprinus stercorarius

Reverse transcriptase activity of an intron encoded polypeptide.

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A 20 × 10³‐base mosaic gene identified on the mitochondrial chromosome of Podospora anserina