Common bean (Phaseolus vulgaris) subtelomeres are highly enriched for khipu, the main satellite DNA identified so far in this genome. Here, we comparatively investigate khipu genomic organization in Phaseolus species from different clades. Additionally, we identified and characterized another satellite repeat, named jumper, associated to khipu. A mixture of P. vulgaris khipu clones hybridized in situ confirmed the presence of khipu-like sequences on subterminal chromosome regions in all Phaseolus species, with differences in the number and intensity of signals between species and when species-specific clones were used. Khipu is present as multimers of ∼500 bp and sequence analyses of cloned fragments revealed close relationship among khipu repeats. The new repeat, named jumper, is a 170-bp satellite sequence present in all Phaseolus species and inserted into the nontranscribed spacer (NTS) of the 5S rDNA in the P. vulgaris genome. Nevertheless, jumper was found as a high-copy repeat at subtelomeres and/or pericentromeres in the Phaseolus microcarpus lineage only. Our data argue for khipu as an important subtelomeric satellite DNA in the genus and for a complex satellite repeat composition of P. microcarpus subtelomeres, which also contain jumper. Furthermore, the differential amplification of these repeats in subtelomeres or pericentromeres reinforces the presence of a dynamic satellite DNA library in Phaseolus.
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http://dx.doi.org/10.1007/s00709-016-0993-8 | DOI Listing |
The eukaryotic genome is packaged into chromatin, which is composed of a nucleosomal filament that coils up to form more compact structures. Chromatin exists in two main forms: euchromatin, which is relatively decondensed and enriched in transcriptionally active genes, and heterochromatin, which is condensed and transcriptionally repressed . It is widely accepted that chromatin architecture modulates DNA accessibility, restricting the access of sequence-specific, gene-regulatory, transcription factors to the genome.
View Article and Find Full Text PDFUnlabelled: is one of the three most frequently mutated genes in age-related clonal hematopoiesis (CH), alongside and . CH can progress to myeloid malignancies including chronic monomyelocytic leukemia (CMML), and is also strongly associated with inflammatory cardiovascular disease and all-cause mortality in humans. DNMT3A and TET2 regulate DNA methylation and demethylation pathways respectively, and loss-of-function mutations in these genes reduce DNA methylation in heterochromatin, allowing de-repression of silenced elements in heterochromatin.
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January 2025
Naturalis Biodiversity Center, Darwinweg 2, 2333 CR Leiden, the Netherlands; IBED, University of Amsterdam, Sciencepark 904, 1098 XH Amsterdam, the Netherlands.
Commun Biol
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Faculty of Life and Environmental Sciences, University of Yamanashi, Yamanashi, Japan.
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View Article and Find Full Text PDFNat Commun
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Laboratory of Structural Biochemistry, Institute of Chemistry and Biochemistry, Freie Universität Berlin, Berlin, Germany.
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