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Discovery of the rpl10 gene in diverse plant mitochondrial genomes and its probable replacement by the nuclear gene for chloroplast RPL10 in two lineages of angiosperms.

Kubo N, Arimura S - DNA Res. (2009)

Bottom Line: In two of them (Brassicaceae and monocots), no nuclear copy of mitochondrial rpl10 is identifiably present, and instead a second copy of nuclear-encoded chloroplast rpl10 is present.Transient assays using green fluorescent protein indicate that this duplicate gene is dual targeted to mitochondria and chloroplasts.We infer that mitochondrial rpl10 has been functionally replaced by duplicated chloroplast counterparts in Brassicaceae and monocots.

View Article: PubMed Central - PubMed

Affiliation: Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Seika, Kyoto, Japan. nk0103@kab.seika.kyoto.jp

ABSTRACT
Mitochondrial genomes of plants are much larger than those of mammals and often contain conserved open reading frames (ORFs) of unknown function. Here, we show that one of these conserved ORFs is actually the gene for ribosomal protein L10 (rpl10) in plant. No rpl10 gene has heretofore been reported in any mitochondrial genome other than the exceptionally gene-rich genome of the protist Reclinomonas americana. Conserved ORFs corresponding to rpl10 are present in a wide diversity of land plant and green algal mitochondrial genomes. The mitochondrial rpl10 genes are transcribed in all nine land plants examined, with five seed plant genes subject to RNA editing. In addition, mitochondrial-rpl10-like cDNAs were identified in EST libraries from numerous land plants. In three lineages of angiosperms, rpl10 is either lost from the mitochondrial genome or a pseudogene. In two of them (Brassicaceae and monocots), no nuclear copy of mitochondrial rpl10 is identifiably present, and instead a second copy of nuclear-encoded chloroplast rpl10 is present. Transient assays using green fluorescent protein indicate that this duplicate gene is dual targeted to mitochondria and chloroplasts. We infer that mitochondrial rpl10 has been functionally replaced by duplicated chloroplast counterparts in Brassicaceae and monocots.

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Mitochondrial genome organization in the vicinity of ORFs that are homologous to orf168 of Marchantia polymorpha mitochondrial DNA. Exons of previously characterized genes, the ORFs potentially encoding the ribosomal protein L10 (RPL10), and other putative ORFs are indicated with hatched, filled, and open boxes, respectively. Group II introns are represented by bent lines. Positions of tRNA gene are marked by filled circles. Genes encoded in sense and antisense strands are placed above and below the horizontal lines, respectively.
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DSP024F1: Mitochondrial genome organization in the vicinity of ORFs that are homologous to orf168 of Marchantia polymorpha mitochondrial DNA. Exons of previously characterized genes, the ORFs potentially encoding the ribosomal protein L10 (RPL10), and other putative ORFs are indicated with hatched, filled, and open boxes, respectively. Group II introns are represented by bent lines. Positions of tRNA gene are marked by filled circles. Genes encoded in sense and antisense strands are placed above and below the horizontal lines, respectively.

Mentions: The locations of the orf168-homologues in mitochondrial genomes relative to flanking genes are conserved among green algae and bryophytes to a substantial (but variable) degree (Fig. 1), whereas there is no linkage conservation of the orf168-homologue to these genes in seed plants (data not shown). This suggests that an ancestral, green-plant gene cluster including the orf168-homologue was destroyed, and each gene within the cluster was dispersed throughout the genome during the evolution of seed plants, as reported by Li et al.7 and as found for many other mitochondrial genes in angiosperm.


Discovery of the rpl10 gene in diverse plant mitochondrial genomes and its probable replacement by the nuclear gene for chloroplast RPL10 in two lineages of angiosperms.

Kubo N, Arimura S - DNA Res. (2009)

Mitochondrial genome organization in the vicinity of ORFs that are homologous to orf168 of Marchantia polymorpha mitochondrial DNA. Exons of previously characterized genes, the ORFs potentially encoding the ribosomal protein L10 (RPL10), and other putative ORFs are indicated with hatched, filled, and open boxes, respectively. Group II introns are represented by bent lines. Positions of tRNA gene are marked by filled circles. Genes encoded in sense and antisense strands are placed above and below the horizontal lines, respectively.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC2818186&req=5

DSP024F1: Mitochondrial genome organization in the vicinity of ORFs that are homologous to orf168 of Marchantia polymorpha mitochondrial DNA. Exons of previously characterized genes, the ORFs potentially encoding the ribosomal protein L10 (RPL10), and other putative ORFs are indicated with hatched, filled, and open boxes, respectively. Group II introns are represented by bent lines. Positions of tRNA gene are marked by filled circles. Genes encoded in sense and antisense strands are placed above and below the horizontal lines, respectively.
Mentions: The locations of the orf168-homologues in mitochondrial genomes relative to flanking genes are conserved among green algae and bryophytes to a substantial (but variable) degree (Fig. 1), whereas there is no linkage conservation of the orf168-homologue to these genes in seed plants (data not shown). This suggests that an ancestral, green-plant gene cluster including the orf168-homologue was destroyed, and each gene within the cluster was dispersed throughout the genome during the evolution of seed plants, as reported by Li et al.7 and as found for many other mitochondrial genes in angiosperm.

Bottom Line: In two of them (Brassicaceae and monocots), no nuclear copy of mitochondrial rpl10 is identifiably present, and instead a second copy of nuclear-encoded chloroplast rpl10 is present.Transient assays using green fluorescent protein indicate that this duplicate gene is dual targeted to mitochondria and chloroplasts.We infer that mitochondrial rpl10 has been functionally replaced by duplicated chloroplast counterparts in Brassicaceae and monocots.

View Article: PubMed Central - PubMed

Affiliation: Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Seika, Kyoto, Japan. nk0103@kab.seika.kyoto.jp

ABSTRACT
Mitochondrial genomes of plants are much larger than those of mammals and often contain conserved open reading frames (ORFs) of unknown function. Here, we show that one of these conserved ORFs is actually the gene for ribosomal protein L10 (rpl10) in plant. No rpl10 gene has heretofore been reported in any mitochondrial genome other than the exceptionally gene-rich genome of the protist Reclinomonas americana. Conserved ORFs corresponding to rpl10 are present in a wide diversity of land plant and green algal mitochondrial genomes. The mitochondrial rpl10 genes are transcribed in all nine land plants examined, with five seed plant genes subject to RNA editing. In addition, mitochondrial-rpl10-like cDNAs were identified in EST libraries from numerous land plants. In three lineages of angiosperms, rpl10 is either lost from the mitochondrial genome or a pseudogene. In two of them (Brassicaceae and monocots), no nuclear copy of mitochondrial rpl10 is identifiably present, and instead a second copy of nuclear-encoded chloroplast rpl10 is present. Transient assays using green fluorescent protein indicate that this duplicate gene is dual targeted to mitochondria and chloroplasts. We infer that mitochondrial rpl10 has been functionally replaced by duplicated chloroplast counterparts in Brassicaceae and monocots.

Show MeSH
Related in: MedlinePlus