During interphase, the chromosomes of eukaryotes decondense and they occupy distinct regions of the nucleus, called chromosome domains or chromosome territories (CTs). In plants, the Rabl's configuration, with telomeres at one pole of nucleus and centromeres at the other, appears to be common, at least in plants with large genomes. It is unclear whether individual chromosomes of plants adopt defined, genetically determined addresses within the nucleus, as is the case in mammals. In this study, the nuclear disposition of alien rye and barley chromosomes and chromosome arm introgressions into wheat while using 3D-FISH in various somatic tissues was analyzed. All of the introgressed chromosomes showed Rabl's orientation, but their relative positions in the nuclei were less clear. While in most cases pairs of introgressed chromosomes occupied discrete positions, their association (proximity) along their entire lengths was rare, and partial association only marginally more frequent. This arrangement is relatively stable in various tissues and during various stages of the cell cycle. On the other hand, the length of a chromosome arm appears to play a role in its positioning in a nucleus: shorter chromosomes or chromosome arms tend to be located closer to the centre of the nucleus, while longer arms are more often positioned at the nuclear periphery.

• Klíčová slova
• 3D-FISH, barley, chromatin, hybrid, introgression, nucleus, rye, wheat,
• MeSH
• buněčné jádro MeSH
• chromatin genetika   MeSH
• chromozomy rostlin * MeSH
• hybridizace in situ fluorescenční * metody   MeSH
• interfáze * genetika   MeSH
• ječmen (rod) genetika   MeSH
• počítačové zpracování obrazu MeSH
• průtoková cytometrie MeSH
• pšenice genetika   MeSH
• žito genetika   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• chromatin MeSH

Despite a long history, the production of useful alien introgression lines in wheat remains difficult mainly due to linkage drag and incomplete genetic compensation. In addition, little is known about the molecular mechanisms underlying the impact of foreign chromatin on plant phenotype. Here, a comparison of the transcriptomes of barley, wheat and a wheat-barley 7HL addition line allowed the transcriptional impact both on 7HL genes of a non-native genetic background and on the wheat gene complement as a result of the presence of 7HL to be assessed. Some 42% (389/923) of the 7HL genes assayed were differentially transcribed, which was the case for only 3% (960/35 301) of the wheat gene complement. The absence of any transcript in the addition line of a suite of chromosome 7A genes implied the presence of a 36 Mbp deletion at the distal end of the 7AL arm; this deletion was found to be in common across the full set of Chinese Spring/Betzes barley addition lines. The remaining differentially transcribed wheat genes were distributed across the whole genome. The up-regulated barley genes were mostly located in the proximal part of the 7HL arm, while the down-regulated ones were concentrated in the distal part; as a result, genes encoding basal cellular functions tended to be transcribed, while those encoding specific functions were suppressed. An insight has been gained into gene transcription in an alien introgression line, thereby providing a basis for understanding the interactions between wheat and exotic genes in introgression materials.

• Klíčová slova
• RNA-seq, alien introgression, chromosomal rearrangement, deletion, gene transcription, transcriptome modification,
• MeSH
• genom rostlinný * MeSH
• ječmen (rod) genetika   metabolismus   MeSH
• pšenice genetika   metabolismus   MeSH
• sekvenční delece MeSH
• transkriptom * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH

The nucleolus is the site of rRNA gene transcription, rRNA processing, and ribosome biogenesis. However, the nucleolus also plays additional roles in the cell. We isolated nucleoli using fluorescence-activated cell sorting (FACS) and identified nucleolus-associated chromatin domains (NADs) by deep sequencing, comparing wild-type plants and null mutants for the nucleolar protein NUCLEOLIN 1 (NUC1). NADs are primarily genomic regions with heterochromatic signatures and include transposable elements (TEs), sub-telomeric regions, and mostly inactive protein-coding genes. However, NADs also include active rRNA genes and the entire short arm of chromosome 4 adjacent to them. In nuc1 null mutants, which alter rRNA gene expression and overall nucleolar structure, NADs are altered, telomere association with the nucleolus is decreased, and telomeres become shorter. Collectively, our studies reveal roles for NUC1 and the nucleolus in the spatial organization of chromosomes as well as telomere maintenance.

• Klíčová slova
• heterochromatin, nuclear architecture, nucleolus, nucleolus-associated chromatin domains, telomere,
• MeSH
• Arabidopsis MeSH
• buněčné jadérko metabolismus   MeSH
• exprese genu * MeSH
• fosfoproteiny metabolismus   MeSH
• genetická transkripce genetika   MeSH
• genom rostlinný * MeSH
• heterochromatin genetika   metabolismus   MeSH
• nukleolin MeSH
• proteiny vázající RNA metabolismus   MeSH
• ribozomální DNA genetika   MeSH
• RNA ribozomální metabolismus   MeSH
• telomery metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• fosfoproteiny MeSH
• heterochromatin MeSH
• proteiny vázající RNA MeSH
• ribozomální DNA MeSH
• RNA ribozomální MeSH