Heat and interchromosomal effects on recombination have been compared for 23 regions comprising the predominantly euchromatic portions of the five arms of the Drosophila genome. Patterns of response are strikingly similar, with both modifiers causing proximal and distal increases and minimal effects in the middle of the arms. Changes in interference for the same regions in the presence of the two modifiers reveal little similarity, except for the X chromosome. The question of independent control of interference and recombination, as well as alternatives for their temporal sequence, is discussed. Recombination response to the two modifiers in the centric heterochromatin of chromosoaime 2 is markedly different from that found in euchromatin. The interchromosomal effect is absent here, whereas heat induces an increase roughly an order of magnitude greater than that found in euchromatin and totally unlike the lack of response in the proximal heterochromatin of the X chromosome. It is proposed that the sequestering of DNA satellite I (thermal dissociation 9-20 degrees lower than that of the other major satellites) in the centromeric heterochromatin of chromosome 2 (but not in X or 3) may account for the increase.
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http://dx.doi.org/10.1093/genetics/89.1.65 | DOI Listing |
Dokl Biochem Biophys
August 2024
Engelhardt Institute of Molecular Biology Russian Academy of Sciences, Moscow, Russia.
Nucleoli form interchromosomal contacts with genes controlling differentiation and carcinogenesis. DUX4 genes specify transcription factor possessing two homeodomains. Previously, using Circular Chromosome Conformation Capture (4С) approach on population of cells, it was demonstrated that DUX4 gene clusters form frequent contacts with nucleoli.
View Article and Find Full Text PDFCells
December 2020
Department of Epigenetic Mechanisms of Gene Expression Regulation, Engelhardt Institute of Molecular Biology Russian Academy of Sciences, 119334 Moscow, Russia.
Chromosomes are organized into 3D structures that are important for the regulation of gene expression and differentiation. Important role in formation of inter-chromosome contacts play rDNA clusters that make up nucleoli. In the course of differentiation, heterochromatization of rDNA units in mouse cells is coupled with the repression or activation of different genes.
View Article and Find Full Text PDFDokl Biochem Biophys
January 2020
Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, Russia.
In order to study the effects of heat shock treatment on the distribution of rDNA contacts at the region possessing DUX genes inside chromosome 4 we used 4C approach. Our data indicate that the treatment removes the frequent rDNA contacts in this region. The recent data on involvement of superenhancers that are decorated by broad H3K27ac marks in the phase separation mechanisms and the previous data demonstrating that these broad marks are the favorite sites of rDNA contacts taken together with our data on sensitivity of the contacts to the heat shock treatment suggest that the phase separation mechanisms are involved in the reversible rDNA-mediated regulation of gene expression via the contacts.
View Article and Find Full Text PDFNat Commun
April 2020
State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, 100871, China.
In higher eukaryotes, heterochromatin is mainly composed of transposable elements (TEs) silenced by epigenetic mechanisms. But, the silencing of certain heterochromatin-associated TEs is disrupted by heat stress. By comparing genome-wide high-resolution chromatin packing patterns under normal or heat conditions obtained through Hi-C analysis, we show here that heat stress causes global rearrangement of the 3D genome in Arabidopsis thaliana.
View Article and Find Full Text PDFNucleus
September 2019
a Chromosome Biochemistry Laboratory, Center for Frontier Research , National Institute of Genetics, Mishima , Shizuoka , Japan.
Cohesin is a ring-shaped, multi-subunit ATPase assembly that is fundamental to the spatiotemporal organization of chromosomes. The ring establishes a variety of chromosomal structures including sister chromatid cohesion and chromatin loops. At the core of the ring is a pair of highly conserved SMC (Structural Maintenance of Chromosomes) proteins, which are closed by the flexible kleisin subunit.
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