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Heat stress enhances the accumulation of polyadenylated mitochondrial transcripts in Arabidopsis thaliana.

Adamo A, Pinney JW, Kunova A, Westhead DR, Meyer P - PLoS ONE (2008)

Bottom Line: We followed up a surprising observation that a large number of mitochondrial transcripts are detectable in microarray experiments that used poly(A)-specific RNA probes, and that these transcript levels are significantly enhanced after heat treatment.We found that the affected transcripts were uncapped transcripts of mitochondrial origin, which were polyadenylated at multiple sites within their 3'region.As many microarrays contain mitochondrial probes, due to the frequent transfer of mitochondrial genes into the genome, these effects need to be considered when interpreting microarray data.

View Article: PubMed Central - PubMed

Affiliation: Center for Plant Sciences, University of Leeds, Leeds, United Kingdom.

ABSTRACT

Background: Polyadenylation of RNA has a decisive influence on RNA stability. Depending on the organisms or subcellular compartment, it either enhances transcript stability or targets RNAs for degradation. In plant mitochondria, polyadenylation promotes RNA degradation, and polyadenylated mitochondrial transcripts are therefore widely considered to be rare and unstable. We followed up a surprising observation that a large number of mitochondrial transcripts are detectable in microarray experiments that used poly(A)-specific RNA probes, and that these transcript levels are significantly enhanced after heat treatment.

Methodology/principal findings: As the Columbia genome contains a complete set of mitochondrial genes, we had to identify polymorphisms to differentiate between nuclear and mitochondrial copies of a mitochondrial transcript. We found that the affected transcripts were uncapped transcripts of mitochondrial origin, which were polyadenylated at multiple sites within their 3'region. Heat-induced enhancement of these transcripts was quickly restored during a short recovery period.

Conclusions/significance: Our results show that polyadenylated transcripts of mitochondrial origin are more stable than previously suggested, and that their steady-state levels can even be significantly enhanced under certain conditions. As many microarrays contain mitochondrial probes, due to the frequent transfer of mitochondrial genes into the genome, these effects need to be considered when interpreting microarray data.

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Related in: MedlinePlus

Profile of polyadenylated and total rpl2 transcripts levels in total RNA extracts from 10-day-old seedlings.Samples were maintained at 24°C or kept at 40°C for two hours. Rpl2 specific values were normalised to Actin2 transcript levels. Especially in the polyadenylated total RNA fraction, rpl2 transcripts are strongly increased after heat treatment.
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pone-0002889-g003: Profile of polyadenylated and total rpl2 transcripts levels in total RNA extracts from 10-day-old seedlings.Samples were maintained at 24°C or kept at 40°C for two hours. Rpl2 specific values were normalised to Actin2 transcript levels. Especially in the polyadenylated total RNA fraction, rpl2 transcripts are strongly increased after heat treatment.

Mentions: To differentiate between total and polyadenylated transcripts, we used random primers or oligo dT primers, respectively, to compare rpl2 transcript levels with and without heat treatment (Fig. 3). In randomly primed RNA pools, rpl2 transcript levels increased about 2-fold after heat treatment in total RNA preparations. A similar tendency was observed, although at a more pronounced level, for polyadenylated RNA pools where heat treatment resulted in a 30-fold increase of rpl2 transcripts in total RNA preparation. This suggests that the heat-specific enhancement of rpl2 transcripts predominantly affects polyadenylated transcripts.


Heat stress enhances the accumulation of polyadenylated mitochondrial transcripts in Arabidopsis thaliana.

Adamo A, Pinney JW, Kunova A, Westhead DR, Meyer P - PLoS ONE (2008)

Profile of polyadenylated and total rpl2 transcripts levels in total RNA extracts from 10-day-old seedlings.Samples were maintained at 24°C or kept at 40°C for two hours. Rpl2 specific values were normalised to Actin2 transcript levels. Especially in the polyadenylated total RNA fraction, rpl2 transcripts are strongly increased after heat treatment.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2483354&req=5

pone-0002889-g003: Profile of polyadenylated and total rpl2 transcripts levels in total RNA extracts from 10-day-old seedlings.Samples were maintained at 24°C or kept at 40°C for two hours. Rpl2 specific values were normalised to Actin2 transcript levels. Especially in the polyadenylated total RNA fraction, rpl2 transcripts are strongly increased after heat treatment.
Mentions: To differentiate between total and polyadenylated transcripts, we used random primers or oligo dT primers, respectively, to compare rpl2 transcript levels with and without heat treatment (Fig. 3). In randomly primed RNA pools, rpl2 transcript levels increased about 2-fold after heat treatment in total RNA preparations. A similar tendency was observed, although at a more pronounced level, for polyadenylated RNA pools where heat treatment resulted in a 30-fold increase of rpl2 transcripts in total RNA preparation. This suggests that the heat-specific enhancement of rpl2 transcripts predominantly affects polyadenylated transcripts.

Bottom Line: We followed up a surprising observation that a large number of mitochondrial transcripts are detectable in microarray experiments that used poly(A)-specific RNA probes, and that these transcript levels are significantly enhanced after heat treatment.We found that the affected transcripts were uncapped transcripts of mitochondrial origin, which were polyadenylated at multiple sites within their 3'region.As many microarrays contain mitochondrial probes, due to the frequent transfer of mitochondrial genes into the genome, these effects need to be considered when interpreting microarray data.

View Article: PubMed Central - PubMed

Affiliation: Center for Plant Sciences, University of Leeds, Leeds, United Kingdom.

ABSTRACT

Background: Polyadenylation of RNA has a decisive influence on RNA stability. Depending on the organisms or subcellular compartment, it either enhances transcript stability or targets RNAs for degradation. In plant mitochondria, polyadenylation promotes RNA degradation, and polyadenylated mitochondrial transcripts are therefore widely considered to be rare and unstable. We followed up a surprising observation that a large number of mitochondrial transcripts are detectable in microarray experiments that used poly(A)-specific RNA probes, and that these transcript levels are significantly enhanced after heat treatment.

Methodology/principal findings: As the Columbia genome contains a complete set of mitochondrial genes, we had to identify polymorphisms to differentiate between nuclear and mitochondrial copies of a mitochondrial transcript. We found that the affected transcripts were uncapped transcripts of mitochondrial origin, which were polyadenylated at multiple sites within their 3'region. Heat-induced enhancement of these transcripts was quickly restored during a short recovery period.

Conclusions/significance: Our results show that polyadenylated transcripts of mitochondrial origin are more stable than previously suggested, and that their steady-state levels can even be significantly enhanced under certain conditions. As many microarrays contain mitochondrial probes, due to the frequent transfer of mitochondrial genes into the genome, these effects need to be considered when interpreting microarray data.

Show MeSH
Related in: MedlinePlus