Expression and Complementation Analyses of a Chloroplast-Localized Homolog of Bacterial RecA in the Moss<i>Physcomitrella patens</i>

Inouye, Takayuki; Odahara, Masaki; Fujita, Tomomichi; Hasebe, Mitsuyasu; Sekine, Yoshiaki

doi:10.1271/bbb.80014

Cited by 23 publications

(28 citation statements)

References 34 publications

(51 reference statements)

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“…Shedge et al (2007) suggested a role for RECA3 in maintaining mitochondrial genome stability; however, the functional relationship between the two RecA proteins and the contribution of RECA2 to recombination in the mitochondrial genome remain unclear. Our subcellular localization analyses of P. patens RecA proteins Inouye et al, 2008) and survey of the P. patens nuclear genome sequence (Rensing et al, 2008) show that P. patens has a single mitochondrial RecA. Thus, our analyses of RECA1 clearly show a role for RecA in plant mitochondria, and here we propose that one of the primary roles of plant mitochondrial RecA is to suppress recombination among the short repeats (<100 bp) scattered throughout the genome.…”

Section: Discussionsupporting

confidence: 52%

“…RecA-like strand transfer activity has been detected in a stromal extract from pea (Pisum sativum) chloroplasts (Cerutti and Jagendorf, 1993) and in soybean (Glycine max) mitochondria (Manchekar et al, 2006). In the moss Physcomitrella patens, two RecA homologs were identified, a mitochondrial-targeted RecA (RECA1) and a chloroplasttargeted RecA (RECA2) Inouye et al, 2008). The RECA1 gene disruptant exhibits a lower rate of recovery of the mitochondrial DNA (mtDNA) from methyl methanesulfonate (MMS)-induced damage , suggesting the involvement of RECA1 in the repair of mtDNA.…”

Section: Introductionmentioning

confidence: 99%

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Suppression of Repeat-Mediated Gross Mitochondrial Genome Rearrangements by RecA in the Moss Physcomitrella patens

Odahara

Kuroiwa

et al. 2009

The Plant Cell

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RecA and its ubiquitous homologs are crucial components in homologous recombination. Besides their eukaryotic nuclear counterparts, plants characteristically possess several bacterial-type RecA proteins localized to chloroplasts and/or mitochondria, but their roles are poorly understood. Here, we analyzed the role of the only mitochondrial RecA in the moss Physcomitrella patens. Disruption of the P. patens mitochondrial recA gene RECA1 caused serious defects in plant growth and development and abnormal mitochondrial morphology. Analyses of mitochondrial DNA in disruptants revealed that frequent DNA rearrangements occurred at multiple loci. Structural analysis suggests that the rearrangements, which in some cases were associated with partial deletions and amplifications of mitochondrial DNA, were due to aberrant recombination between short (<100 bp) direct and inverted repeats in which the sequences were not always identical. Such repeats are abundant in the mitochondrial genome, and interestingly many are located in group II introns. These results suggest that RECA1 does not promote but rather suppresses recombination among short repeats scattered throughout the mitochondrial genome, thereby maintaining mitochondrial genome stability. We propose that RecA-mediated homologous recombination plays a crucial role in suppression of short repeat-mediated genome rearrangements in plant mitochondria.

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Section: Discussionsupporting

confidence: 52%

Section: Introductionmentioning

confidence: 99%

Suppression of Repeat-Mediated Gross Mitochondrial Genome Rearrangements by RecA in the Moss Physcomitrella patens

Odahara

Kuroiwa

et al. 2009

The Plant Cell

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“…The most important factor for homologous recombination is the extent and degree of sequence similarity between the recombining fragments and is mediated by recombination/repair en- zymes. The RecA protein is mainly responsible for facilitating recombination, and its homolog has been identified in land plant plastids (Cerutti et al, 1992(Cerutti et al, , 1993Inouye et al, 2008). Studies demonstrate a loglinear relationship between recombination rate and the degree of sequence divergence, independent of the activity of the mismatch repair system (Shen and Huang, 1986;Majewski and Cohan, 1998).…”

Section: Discussionmentioning

confidence: 99%

The Role of Heterologous Chloroplast Sequence Elements in Transgene Integration and Expression

et al. 2010

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Heterologous regulatory elements and flanking sequences have been used in chloroplast transformation of several crop species, but their roles and mechanisms have not yet been investigated. Nucleotide sequence identity in the photosystem II protein D1 (psbA) upstream region is 59% across all taxa; similar variation was consistent across all genes and taxa examined. Secondary structure and predicted Gibbs free energy values of the psbA 5# untranslated region (UTR) among different families reflected this variation. Therefore, chloroplast transformation vectors were made for tobacco (Nicotiana tabacum) and lettuce (Lactuca sativa), with endogenous (Nt-Nt, Ls-Ls) or heterologous (Nt-Ls, Ls-Nt) psbA promoter, 5# UTR and 3# UTR, regulating expression of the anthrax protective antigen (PA) or human proinsulin (Pins) fused with the cholera toxin B-subunit (CTB). Unique lettuce flanking sequences were completely eliminated during homologous recombination in the transplastomic tobacco genomes but not unique tobacco sequences. Nt-Ls or Ls-Nt transplastomic lines showed reduction of 80% PA and 97% CTB-Pins expression when compared with endogenous psbA regulatory elements, which accumulated up to 29.6% total soluble protein PA and 72.0% total leaf protein CTB-Pins, 2-fold higher than Rubisco. Transgene transcripts were reduced by 84% in Ls-Nt-CTB-Pins and by 72% in Nt-Ls-PA lines. Transcripts containing endogenous 5# UTR were stabilized in nonpolysomal fractions. Stromal RNA-binding proteins were preferentially associated with endogenous psbA 5# UTR. A rapid and reproducible regeneration system was developed for lettuce commercial cultivars by optimizing plant growth regulators. These findings underscore the need for sequencing complete crop chloroplast genomes, utilization of endogenous regulatory elements and flanking sequences, as well as optimization of plant growth regulators for efficient chloroplast transformation.Over the expanse of time since the endosymbiotic events that led to the establishment of plant organelles, plant cells have evolved elaborate mechanisms to coordinate the expression of plastid genes with the changing developmental and functional requirements of the cell. In addition to the nucleus-encoded, plastidlocalized RNA polymerase, the nucleus controls the expression of a suite of s-factors required for the active transcription of photosynthetic genes by the plastidencoded RNA polymerase (PEP), with PEP itself being transcribed by nucleus-encoded, plastid-localized RNA polymerase (Allison et al., 1996;Hess and Borner, 1999). Nuclear control over translation of plastid mRNA is exerted through the activities of numerous plastid-localized RNA-binding proteins (RBPs). RBPs appear to have a tight affinity for their cognate sequences in plastid mRNAs, and studies have demonstrated that their interactions are specific for particular genes (Nakamura et al., 1999(Nakamura et al., , 2001Shen et al., 2001;Meierhoff et al., 2003;Schmitz-Linneweber et al., 2005.Plastid mRNAs, expressed as monocistrons or polycistro...

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“…In contrast, both mitochondrial and plastidial RecAs are present in land plants. Two RECA genes have been retained in the moss Physcomitrella patens (one for each organellar compartment [Odahara et al, 2007;Inouye et al, 2008]), and three RECA genes are present in Arabidopsis, named RECA1, RECA2, and RECA3 (Shedge et al, 2007). Protein-GFP fusions showed that RECA1 and RECA3 are targeted to plastids and mitochondria, respectively, whereas RECA2 is dual targeted to both organelles.…”

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confidence: 99%

RecA-Dependent DNA Repair Results in Increased Heteroplasmy of the Arabidopsis Mitochondrial Genome

et al. 2012

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Plant mitochondria have very active DNA recombination activities that are responsible for its plastic structures and that should be involved in the repair of double-strand breaks in the mitochondrial genome. Little is still known on plant mitochondrial DNA repair, but repair by recombination is believed to be a major determinant in the rapid evolution of plant mitochondrial genomes. In flowering plants, mitochondria possess at least two eubacteria-type RecA proteins that should be core components of the mitochondrial repair mechanisms. We have performed functional analyses of the two Arabidopsis (Arabidopsis thaliana) mitochondrial RecAs (RECA2 and RECA3) to assess their potential roles in recombination-dependent repair. Heterologous expression in Escherichia coli revealed that RECA2 and RECA3 have overlapping as well as specific activities that allow them to partially complement bacterial repair pathways. RECA2 and RECA3 have similar patterns of expression, and mutants of either display the same molecular phenotypes of increased recombination between intermediate-size repeats, thus suggesting that they act in the same recombination pathways. However, RECA2 is essential past the seedling stage and should have additional important functions. Treatment of plants with several DNA-damaging drugs further showed that RECA3 is required for different recombination-dependent repair pathways that significantly contribute to plant fitness under stress. Replication repair of double-strand breaks results in the accumulation of crossovers that increase the heteroplasmic state of the mitochondrial DNA. It was shown that these are transmitted to the plant progeny, enhancing the potential for mitochondrial genome evolution.

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Expression and Complementation Analyses of a Chloroplast-Localized Homolog of Bacterial RecA in the MossPhyscomitrella patens

Cited by 23 publications

References 34 publications

Suppression of Repeat-Mediated Gross Mitochondrial Genome Rearrangements by RecA in the Moss Physcomitrella patens

Suppression of Repeat-Mediated Gross Mitochondrial Genome Rearrangements by RecA in the Moss Physcomitrella patens

The Role of Heterologous Chloroplast Sequence Elements in Transgene Integration and Expression

RecA-Dependent DNA Repair Results in Increased Heteroplasmy of the Arabidopsis Mitochondrial Genome

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