The Triploid Endosperm Genome of<i>Arabidopsis</i>Adopts a Peculiar, Parental-Dosage-Dependent Chromatin Organization

Baroux, Célia; Pečinka, Aleš; Fuchs, Jörg; Schubert, Ingo; Grossniklaus, Ueli

doi:10.1105/tpc.106.046235

Cited by 87 publications

(83 citation statements)

References 48 publications

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“…The 4C, 6C, and 12C fractions correspond to nuclei with a replicated genome either in the course of a regular cell cycle or, most likely, as a result of endoreduplication (Larkins et al 2001). Measurements of nuclear volume normalized for the ploidy confirmed that endosperm nuclei harbor a less condensed chromatin compared to somatic seed nuclei (Online Resource 1), similar to what was previously reported in whole-mount seed tissues (Baroux et al 2007). This finding indicates that the isolation procedure preserves global nuclear architecture.…”

Section: Geometrical Characteristics Of Flow-sorted Seed Nucleisupporting

confidence: 67%

“…As in somatic tissues (Fransz et al 2002), endosperm nuclei of Arabidopsis harbor heterochromatic CCs, comprising CENs and the 45S ribosomal DNA (rDNA) repeats of the nucleolus organizer regions (NORs) as shown by FISH (Baroux et al 2007). Arabidopsis possess a haploid complement of five chromosomes with two NORs located on chromosomes 2 and 4 (Fransz et al 2002).…”

Section: Centromeres Frequently Associate In Endosperm Nucleimentioning

confidence: 99%

“…To compare chromosome organization in endosperm nuclei with that in nuclei from the surrounding tissues, we flowsorted seed nuclei according to their DNA content as described (Baroux et al 2007). We isolated 2C and 4C fractions as well as endosperm-specific 3C and 6C fractions from diploid plants and 6C and 12C endosperm nuclei from tetraploid plants of the same accession.…”

Section: Geometrical Characteristics Of Flow-sorted Seed Nucleimentioning

confidence: 99%

“…Hence, the endosperm genome consists of two maternal and one paternal chromosome complement. This triploid genome has a peculiar chromatin organization, characterized by a specific heterochromatin fraction that is interspersed within euchromatin and modulated by the dosage of parental genomes (Baroux et al 2007). We used FISH to study the organization of endosperm nuclei in more detail.…”

Section: Introductionmentioning

confidence: 99%

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Non-random chromosome arrangement in triploid endosperm nuclei

et al. 2016

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The endosperm is at the center of successful seed formation in flowering plants. Being itself a product of fertilization, it is devoted to nourish the developing embryo and typically possesses a triploid genome consisting of two maternal and one paternal genome complement. Interestingly, endosperm development is controlled by epigenetic mechanisms conferring parent-of-origin-dependent effects that influence seed development. In the model plant Arabidopsis thaliana, we have previously described an endosperm-specific heterochromatin fraction, which increases with higher maternal, but not paternal, genome dosage. Here, we report a detailed analysis of chromosomal arrangement and association frequency in endosperm nuclei. We found that centromeric FISH signals in isolated nuclei show a planar alignment that may results from a semi-rigid, connective structure between chromosomes. Importantly, we found frequent pairwise association of centromeres, chromosomal segments, and entire arms of chromosomes in 3C endosperm nuclei. These associations deviate from random expectations predicted by numerical simulations. Therefore, we suggest a non-random chromosomal organization in the triploid nuclei of Arabidopsis endosperm. This contrasts with the prevailing random arrangement of chromosome territories in somatic nuclei. Based on observations on a series of nuclei with varying parental genome ratios, we propose a model where chromosomes associate pairwise involving one maternal and one paternal complement. The functional implications of this predicted chromosomal arrangement are discussed.

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Section: Geometrical Characteristics Of Flow-sorted Seed Nucleisupporting

confidence: 67%

Section: Centromeres Frequently Associate In Endosperm Nucleimentioning

confidence: 99%

Section: Geometrical Characteristics Of Flow-sorted Seed Nucleimentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Non-random chromosome arrangement in triploid endosperm nuclei

et al. 2016

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“…33 Carrying on the characterization of endosperm nuclei, Celia Baroux (Z€ urich, Switzerland) presented evidence for frequent associations of the centromeres and chromosomal segments in endosperm nuclei fitting a non-random, pair-wise association model. The analysis of nuclei with imbalanced parental genome contributions led the authors to propose a hypothetical model whereby association of parental homologs together with the formerly reported heterochromatinization of excessive maternal genomic regions may play a role in regulating dosage compensation in the endosperm.…”

Section: Organized Genome In An Organized Nucleusmentioning

confidence: 99%

The many faces of plant chromatin: Meeting summary of the 4th European workshop onplantchromatin 2015, Uppsala, Sweden

Mozgová¹,

Köhler²,

Gaudin³

et al. 2015

Epigenetics

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In June 2015, the fourth European Workshop on Plant Chromatin took place in Uppsala, Sweden, bringing together 80 researchers studying various aspects of plant chromatin and epigenetics. The intricate relationships between plant chromatin dynamics and gene expression change, chromatin organization within the plant cell nucleus, and the impact of chromatin structure on plant development were discussed. Among the main highlights of the meeting were an evergrowing list of newly identified players in chromatin structure establishment and the development of novel tools and approaches to foster our understanding of chromatinmediated gene regulation, taking into account the context of the plant cell nucleus and its architecture. In this report, we summarize some of the main advances and prospects of plant chromatin research presented at this meeting.

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