<i>In planta</i> quantification of endoreduplication using fluorescent <i>in situ</i> hybridization (FISH)

Bourdon, Matthieu; Coriton, Olivier; Pirrello, Julien; Chéniclet, Catherine; Brown, Spencer; Poujol, Christel; Chevalier, Christian; Renaudin, Jean-Pierre; Frangne, Nathalie

doi:10.1111/j.1365-313x.2011.04568.x

Cited by 44 publications

(44 citation statements)

References 38 publications

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“…Applying~100-kb BAC probes for FISH, Bourdon et al (2011) describe an almost complete separation of sister chromatids in endopolyploid pericarp nuclei of up to 128C of tomato fruits. Concordantly, we demonstrate a high degree of positional sister chromatid separation in endopolyploid nuclei along chromosome arms of A. thaliana.…”

Section: Discussionmentioning

confidence: 99%

Interphase chromatin organisation in Arabidopsis nuclei: constraints versus randomness

2012

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The spatial chromatin organisation and molecular interactions within and between chromatin domains and chromosome territories (CTs) are essential for fundamental processes such as replication, transcription and DNA repair via homologous recombination. To analyse the distribution and interaction of whole CTs, centromeres, (sub)telomeres and ~100-kb interstitial chromatin segments in endopolyploid nuclei, specific FISH probes from Arabidopsis thaliana were applied to 2-64C differentiated leaf nuclei. Whereas CTs occupy a distinct and defined volume of the nucleus and do not obviously intermingle with each other in 2-64C nuclei, ~100-kb sister chromatin segments within these CTs become more non-cohesive with increasing endopolyploidy. Centromeres, preferentially located at the nuclear periphery, may show ring- or half-moon like shapes in 2C and 4C nuclei. Sister centromeres tend to associate up to the 8C level. From 16C nuclei on, they become progressively separated. The higher the polyploidy level gets, the more separate chromatids are present. Due to sister chromatid separation in highly endopolyploid nuclei, the centromeric histone variant CENH3, the 180-bp centromeric repeats and pericentromeric heterochromatin form distinct subdomains at adjacent but not intermingling positions. The (sub)telomeres are frequently associated with each other and with the nucleolus and less often with centromeres. The extent of chromatid separation and of chromatin decondensation at subtelomeric chromatin segments varies between chromosome arms. A mainly random distribution and similar shapes of CTs even at higher ploidy levels indicate that in general no substantial CT reorganisation occurs during endopolyploidisation. Non-cohesive sister chromatid regions at chromosome arms and at the (peri)centromere are accompanied by a less dense chromatin conformation in highly endopolyploid nuclei. We discuss the possible function of this conformation in comparison to transcriptionally active regions at insect polytene chromosomes.

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Section: Discussionmentioning

confidence: 99%

Interphase chromatin organisation in Arabidopsis nuclei: constraints versus randomness

2012

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“…the presence of two homogeneous large signals for 45S rDNA as compared with two 'clouds' of clustered hybridisation dots for BAC sequences . This difference can be explained by the fact that the 45S rDNA repeats encompass a much larger chromosomal sequence than any BAC probe (respectively, ~20 Mb versus 0.1 Mb on average) (Chang et al, 2008;Bourdon et al, 2011). In addition, untranscribed copies of 45S rDNA are often condensed and located just outside the nucleolus and may contribute to this large hybridisation signal (Heslop-Harrison and Schwarzacher, 2011).…”

Section: Discussionmentioning

confidence: 99%

Evidence for karyoplasmic homeostasis during endoreduplication and a ploidy-dependent increase in gene transcription during tomato fruit growth

et al. 2012

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SUMMARYEndopolyploidy is a widespread process that corresponds to the amplification of the genome in the absence of mitosis. In tomato, very high ploidy levels (up to 256C) are reached during fruit development, concomitant with very large cell sizes. Using cellular approaches (fluorescence and electron microscopy) we provide a structural analysis of endoreduplicated nuclei at the level of chromatin and nucleolar organisation, nuclear shape and relationship with other cellular organelles such as mitochondria. We demonstrate that endopolyploidy in pericarp leads to the formation of polytene chromosomes and markedly affects nuclear structure. Nuclei manifest a complex shape, with numerous deep grooves that are filled with mitochondria, affording a fairly constant ratio between nuclear surface and nuclear volume. We provide the first direct evidence that endopolyploidy plays a role in increased transcription of rRNA and mRNA on a per-nucleus basis. Overall, our results provide quantitative evidence in favour of the karyoplasmic theory and show that endoreduplication is associated with complex cellular organisation during tomato fruit development.

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“…S8). As DNA size is reflected in nuclear size (Bourdon et al, 2011;Iwata et al, 2011), we next estimated the DNA size of the enlarged nuclei by quantifying the size of DAPI-labeled nuclei. In WT, the size of the enlarged nuclei was more than 8-fold larger compared with those of root cap cells (2C control) (supplementary material Fig.…”

Section: Vag1-mediated Endoreduplication Is Crucial To the Initiationmentioning

confidence: 99%

Endoreduplication-mediated initiation of symbiotic organ development in Lotus japonicus

et al. 2014

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Many leguminous plants have a unique ability to reset and alter the fate of differentiated root cortical cells to form new organs of nitrogenfixing root nodules during legume-Rhizobium symbiosis. Recent genetic studies on the role of cytokinin signaling reveal that activation of cytokinin signaling is crucial to the nodule organogenesis process. However, the genetic mechanism underlying the initiation of nodule organogenesis is poorly understood due to the low number of genes that have been identified. Here, we have identified a novel nodulation-deficient mutant named vagrant infection thread 1 (vag1) after suppressor mutant screening of spontaneous nodule formation 2, a cytokinin receptor gain-of-function mutant in Lotus japonicus. The VAG1 gene encodes a protein that is putatively orthologous to Arabidopsis ROOT HAIRLESS 1/HYPOCOTYL 7, a component of the plant DNA topoisomerase VI that is involved in the control of endoreduplication. Nodule phenotype of the vag1 mutant shows that VAG1 is required for the ploidy-dependent cell growth of rhizobial-infected cells. Furthermore, VAG1 mediates the onset of endoreduplication in cortical cells during early nodule development, which may be essential for the initiation of cortical cell proliferation that leads to nodule primordium formation. In addition, cortical infection is severely impaired in the vag1 mutants, whereas the epidermal infection threads formation is normal. This suggests that the VAG1-mediated endoreduplication of cortical cells may be required for the guidance of symbiotic bacteria to host meristematic cells.

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In planta quantification of endoreduplication using fluorescent in situ hybridization (FISH)

Cited by 44 publications

References 38 publications

Interphase chromatin organisation in Arabidopsis nuclei: constraints versus randomness

Interphase chromatin organisation in Arabidopsis nuclei: constraints versus randomness

Evidence for karyoplasmic homeostasis during endoreduplication and a ploidy-dependent increase in gene transcription during tomato fruit growth

Endoreduplication-mediated initiation of symbiotic organ development in Lotus japonicus

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