Characterization of a plant mitochondrial active chromosome

Fey, Julien; Vermel, Matthieu; Grienenberger, Jean‐Michel; Maréchal-Drouard, Laurence; Gualberto, José M.

doi:10.1016/s0014-5793(99)01140-0

Cited by 19 publications

(21 citation statements)

References 16 publications

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“…Plant Material, cDNA Synthesis, and Polymerase Chain Reaction Amplification-Mitochondria were isolated from potato tubers (var Bintje) by differential centrifugations and purification on Percoll gradients as described previously (18). Mitochondrial RNAs (10 g) from potato tubers were incubated with 10 units of DNase I for 30 min at 37°C.…”

Section: Methodsmentioning

confidence: 99%

“…Mitochondrial RNAs (10 g) from potato tubers were incubated with 10 units of DNase I for 30 min at 37°C. After phenol-chloroform extraction and ethanol precipitation, RNAs were reverse-transcribed using an oligo(dT) 18 -adapter primer (Table I) and Moloney-murine leukemia virus reverse transcriptase (Stratagene). Aliquots of cDNA reactions were subjected to PCR 1 amplification using the adapter primer in combination with an atp9 gene-specific primer (P1, P2, or P3, Table I) and Taq DNA polymerase (Life Technologies, Inc.).…”

Section: Methodsmentioning

confidence: 99%

“…The polyadenylation site 3Ј to the stem-loop (site c) is the only site that is detected in a relatively A-rich region (4 A nucleotides out of 5). Therefore, site c is the only polyadenylation site in the 3Ј-UTR of atp9 mRNAs for which we cannot exclude an artifactual priming of the oligo(dT) 18 -adapter primer during cDNA synthesis.…”

Section: Characterization Of Polyadenylated Atp9 Mrnas In Potato-mentioning

confidence: 99%

“…First-strand cDNA was synthesized from potato mitochondrial RNAs using an oligo(dT) 18 -adapter primer. PCR amplification experiments were then conducted using an atp9 gene-specific primer (P1, P2, or P3) and an adapter primer.…”

Section: Characterization Of Polyadenylated Atp9 Mrnas In Potato-mentioning

confidence: 99%

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Plant Mitochondrial Polyadenylated mRNAs Are Degraded by a 3′- to 5′-Exoribonuclease Activity, Which Proceeds Unimpeded by Stable Secondary Structures

Gagliardi¹,

Perrin²,

Maréchal-Drouard³

et al. 2001

Journal of Biological Chemistry

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Recently, we and others have reported that mRNAs may be polyadenylated in plant mitochondria, and that polyadenylation accelerates the degradation rate of mRNAs. To further characterize the molecular mechanisms involved in plant mitochondrial mRNA degradation, we have analyzed the polyadenylation and degradation processes of potato atp9 mRNAs. The overall majority of polyadenylation sites of potato atp9 mRNAs is located at or in the vicinity of their mature 3-extremities. We show that a 3-to 5-exoribonuclease activity is responsible for the preferential degradation of polyadenylated mRNAs as compared with non-polyadenylated mRNAs, and that 20 -30 adenosine residues constitute the optimal poly(A) tail size for inducing degradation of RNA substrates in vitro. The addition of as few as seven non-adenosine nucleotides 3 to the poly(A) tail is sufficient to almost completely inhibit the in vitro degradation of the RNA substrate. Interestingly, the exoribonuclease activity proceeds unimpeded by stable secondary structures present in RNA substrates. From these results, we propose that in plant mitochondria, poly(A) tails added at the 3 ends of mRNAs promote an efficient 3-to 5-degradation process.The control of mRNA stability constitutes an important aspect of the regulation of gene expression in all organisms. Polyadenylation of mRNAs is involved in the control of mRNA stability, however, with two significantly different roles depending on the organism or subcellular compartment concerned. Polyadenylation is required for stabilizing virtually all nuclear-encoded mRNAs in all eukaryotes. In contrast, polyadenylation targets mRNAs for degradation in eubacteria (1, 2), chloroplasts (3-6), plant mitochondria (7-9), and trypanosome mitochondria (10). In eubacteria and chloroplasts, degradation of mRNAs is initiated by endonucleolytic cleavages. The resulting fragments are then degraded by 3Ј-to 5Ј-exonuclease activities (1, 5). In both systems, polyadenylation targets endonucleolytic cleavage products for rapid degradation. In chloroplasts, structured mature 3Ј ends are poor substrates for polyadenylation as compared with the internal RNA fragments generated by endonuclease(s) (5, 6).In plant mitochondria, molecular mechanisms involved in mRNA stability or degradation are still poorly understood (11). For instance, no proteins involved in these processes have been formally identified, although several candidate genes have now been identified since the completion of the nuclear genome sequence of Arabidopsis thaliana. Stable secondary structures can be predicted at the 3Ј-extremities of some but not all plant mitochondrial mRNAs (12). When present, these structures appear to be involved in stabilizing the transcripts (13-15) and in the correct processing of 3Ј-extremities rather than being signals for transcription termination (15). Mature 3Ј termini of plant mitochondria mRNAs are generated by 3Ј-processing of longer pre-mRNA molecules (15), and stable mature mRNAs are not constitutively polyadenylated at their 3Ј-extremit...

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Characterization Of Polyadenylated Atp9 Mrnas In Potato-mentioning

confidence: 99%

Section: Characterization Of Polyadenylated Atp9 Mrnas In Potato-mentioning

confidence: 99%

See 2 more Smart Citations

Plant Mitochondrial Polyadenylated mRNAs Are Degraded by a 3′- to 5′-Exoribonuclease Activity, Which Proceeds Unimpeded by Stable Secondary Structures

Gagliardi¹,

Perrin²,

Maréchal-Drouard³

et al. 2001

Journal of Biological Chemistry

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“…Bintje) with a juice extractor as described (37). Proteins were synthesized from the corresponding cDNA clones in pBluescript vector by coupled transcription/translation in the presence of [ 35 S]methionine according the supplier's instruction (Promega).…”

mentioning

confidence: 99%

CCME, a Nuclear-encoded Heme-binding Protein Involved in Cytochrome c Maturation in Plant Mitochondria

Spielewoy

Schulz

Grienenberger

et al. 2001

Journal of Biological Chemistry

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The maturation of c-type cytochromes requires the covalent attachment of the heme cofactor to the apoprotein. For this process, plant mitochondria follow a pathway distinct from that of animal or yeast mitochondria, closer to that found in ␣-and ␥-proteobacteria. We report the first characterization of a nuclear-encoded component, namely AtCCME, the Arabidopsis thaliana orthologue of CcmE, a periplasmic heme chaperone in bacteria. AtCCME is targeted to mitochondria, and its N-terminal signal peptide is cleaved upon import. At-CCME is a peripheral protein of the mitochondrial inner membrane, and its major hydrophilic domain is oriented toward the intermembrane space. Although a At-CCME (Met 79 -Ser 256) is not fully able to complement an Escherichia coli CcmE mutant strain for bacterial holocytochrome c production, it is able to bind heme covalently through a conserved histidine, a feature previously shown for E. coli CcmE. Our results suggest that AtCCME is important for cytochrome c maturation in A. thaliana mitochondria and that its heme-binding function has been conserved evolutionary between land plant mitochondria and ␣-proteobacteria.

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