No Neocentric Activity on &lt;i&gt;Aegilops markgrafii&lt;/i&gt; Chromosome E

Schubert, Veit

doi:10.1159/000318996

Cited by 4 publications

(4 citation statements)

References 81 publications

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“…In Bromus marginatus and B. pseudolaevipes hybrids ( Walters, 1952 ), Aegilops markgrafii ( Schubert, 2011 ), and wheat chromosomes in the progeny from Triticale × tritordeum hybrids ( Carvalho et al, 2008 ) a stretched constriction during meiosis, similar to the one found in rye 5RL, was described. In A. markgrafii this constriction is not related to neocentromeric activity since cenH3 and microtubules are exclusively found at the endogenous centromere ( Schubert, 2011 ). Whether constrictions in Bromus or wheat acquire kinetic activity is not documented.…”

Section: Other Types Of Neocentromeresmentioning

confidence: 88%

Atypical centromeres in plants—what they can tell us

2015

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The centromere, visible as the primary constriction of condensed metaphase chromosomes, is a defined chromosomal locus essential for genome stability. It mediates transient assembly of a multi-protein complex, the kinetochore, which enables interaction with spindle fibers and thus faithful segregation of the genetic information during nuclear divisions. Centromeric DNA varies in extent and sequence composition among organisms, but a common feature of almost all active eukaryotic centromeres is the presence of the centromeric histone H3 variant cenH3 (a.k.a. CENP-A). These typical centromere features apply to most studied species. However, a number of species display “atypical” centromeres, such as holocentromeres (centromere extension along almost the entire chromatid length) or neocentromeres (ectopic centromere activity). In this review, we provide an overview of different atypical centromere types found in plants including holocentromeres, de novo formed centromeres and terminal neocentromeres as well as di-, tri- and metapolycentromeres (more than one centromere per chromosomes). We discuss their specific and common features and compare them to centromere types found in other eukaryotic species. We also highlight new insights into centromere biology gained in plants with atypical centromeres such as distinct mechanisms to define a holocentromere, specific adaptations in species with holocentromeres during meiosis or various scenarios leading to neocentromere formation.

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Section: Other Types Of Neocentromeresmentioning

confidence: 88%

Atypical centromeres in plants—what they can tell us

2015

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“…We found frequent decondensation of a chromatin segment at the subtelomere of bottom arm of A. thaliana chromosome 3. Similarly, a single chromosome of Aegilops markgrafii (Greuter) Hammer contains such a stretched domain visible at an interstitial position during meiosis (Schubert 2011). In both cases it is not yet clear whether chromatin relaxation is related to transcriptional activity.…”

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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“…Dependent on the epitope used for the generation of the antibody, some of the CENH3 antibodies cross-react with CENH3 of related species (e.g. anti rice-CENH3 recognizes Aegilops markgrafii [Schubert, 2010], Coix lacrymajobi [Han et al, 2010], maize [Jin et al, 2004], sugarcane , wheat [Liu et al, 2008;Zhang et al, 2010], barley [Nasuda et al, 2005;Houben et al, 2007;Zhang and Dawe, 2012], and rye or only the species used for the generation of the antibody e.g. A. thaliana [Talbert et al, 2002] and barley [Sanei et al, 2011]).…”

Section: Anti-phosphorylatedmentioning

confidence: 99%

Anti-Phosphorylated Histone H2AThr120: A Universal Microscopic Marker for Centromeric Chromatin of Mono- and Holocentric Plant Species

Demidov

Schubert

Kumke

et al. 2014

Cytogenet Genome Res

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Based on the analysis of 20 different monocot and eudicot species, we propose that the centromeric distribution of the phosphorylated histone H2AThr120 is evolutionary highly conserved across species with mono- and holocentric chromosomes. Therefore, antibodies recognizing the phosphorylated threonine 120 of the histone H2A can serve as a universal marker for the cytological detection of centromeres of mono- and holokinetic plant species. In addition, super resolution microscopy of signals specific to the centromere-specific histone H3 variant CENH3 and to H2AThr120ph revealed that these histone variants are incorporated into different nucleosomes, which form distinct, partly intermingled chromatin domains. This specific arrangement of both histone variants suggests different centromeric functions during the cell cycle.

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No Neocentric Activity on <i>Aegilops markgrafii</i> Chromosome E

Cited by 4 publications

References 81 publications

Atypical centromeres in plants—what they can tell us

Atypical centromeres in plants—what they can tell us

Interphase chromatin organisation in Arabidopsis nuclei: constraints versus randomness

Anti-Phosphorylated Histone H2AThr120: A Universal Microscopic Marker for Centromeric Chromatin of Mono- and Holocentric Plant Species

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