Interphase Chromosome Organization in the Brassicaceae
| Authors | |
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| Year of publication | 2020 |
| Type | Conference abstract |
| MU Faculty or unit | |
| Citation | |
| Description | During interphase, chromosomes assume a largely decondensed state. However, chromatin is still nonrandomly arranged within the nuclear space. Each chromosome occupies a limited, exclusive nuclear subdomain, known as chromosome territory (CTs). In many plant species with relatively large genomes, chromosomes during interphase adopt Rabl configuration, with telomeres and centromeres located at opposite poles of the nucleus. However, this model is not universal as showed for grass species with small genome sizes. In the small Arabidopsis genome, the non-Rabl interphase organization has been described as the chromocenter (CC)-loop model or rosette-like organization. This pattern is characterized by heterochromatic CCs located at the nuclear periphery with emanating euchromatic loops comprising the ten chromosome arms, and telomeres usually clustered around the nucleolus. Nevertheless, the small Arabidopsis genome is not necessarily representative of more than 3,600 crucifer species displaying a 50-fold genome size variation. Apart the Arabidopsis genus, surprisingly little is known about the side-by-side arrangement of hetero- and homologous interphase CTs in other crucifer or eudicot species. We aimed to verify the hypothesis that crucifers exhibit at least two different patterns of interphase organization and identify the determining (phylo)genomic features (e.g. genome size, phylogenetic position). We used the method of fluorescence in situ hybridization to analyze telomere/centromere positioning in interphase nuclei in selected Brassicaceae species with constrasting genome sizes and evolutionary history. Our preliminary data suggest that Brassicaceae species with (very) small genome sizes have the rosette-like interphase organization in somatic cells isolated from different tissues (flower, leaf, stem and root), and that telomeres do not cluster around the nucleolus in interphase nuclei in crucifers with large genomes. Interestingly, interphase organization seems to be tissue-specific in the species with intermediate genome size, both rosette-like organization and random telomere/centromere positioning was observed. |
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