scholarly journals Faculty Opinions recommendation of Compressive force induces reversible chromatin condensation and cell geometry dependent transcriptional response.

2018 ◽  
Author(s):  
Martin A Schwartz
Keyword(s):  
Chromatin Condensation ◽  
Compressive Force ◽  
Transcriptional Response ◽  
Cell Geometry

scholarly journals Compressive force induces reversible chromatin condensation and cell geometry–dependent transcriptional response

2018 ◽  
Vol 29 (25) ◽  
pp. 3039-3051 ◽  
Author(s):  
Karthik Damodaran ◽  
Saradha Venkatachalapathy ◽  
Farid Alisafaei ◽  
A. V. Radhakrishnan ◽  
Doorgesh Sharma Jokhun ◽  
...  
Keyword(s):  
Transcriptome Analysis ◽  
Chromatin Condensation ◽  
Compressive Force ◽  
Transcriptional Response ◽  
Quantitative Model ◽  
Mouse Fibroblast ◽  
Cell Geometry ◽  
Connective Tissues ◽  
Actomyosin Contractility ◽  
The Impact

Fibroblasts exhibit heterogeneous cell geometries in tissues and integrate both mechanical and biochemical signals in their local microenvironment to regulate genomic programs via chromatin remodelling. While in connective tissues fibroblasts experience tensile and compressive forces (CFs), the role of compressive forces in regulating cell behavior and, in particular, the impact of cell geometry in modulating transcriptional response to such extrinsic mechanical forces is unclear. Here we show that CF on geometrically well-defined mouse fibroblast cells reduces actomyosin contractility and shuttles histone deacetylase 3 (HDAC3) into the nucleus. HDAC3 then triggers an increase in the heterochromatin content by initiating removal of acetylation marks on the histone tails. This suggests that, in response to CF, fibroblasts condense their chromatin and enter into a transcriptionally less active and quiescent states as also revealed by transcriptome analysis. On removal of CF, the alteration in chromatin condensation was reversed. We also present a quantitative model linking CF-dependent changes in actomyosin contractility leading to chromatin condensation. Further, transcriptome analysis also revealed that the transcriptional response of cells to CF was geometry dependent. Collectively, our results suggest that CFs induce chromatin condensation and geometry-dependent differential transcriptional response in fibroblasts that allows maintenance of tissue homeostasis.

scholarly journals Cell geometry, signal dampening, and a bimodal transcriptional response underlie the spatial precision of an ERK-mediated embryonic induction

2021 ◽  
Author(s):  
Géraldine Williaume ◽  
Sophie de Buyl ◽  
Cathy Sirour ◽  
Nicolas Haupaix ◽  
Rossana Bettoni ◽  
...  
Keyword(s):  
Transcriptional Response ◽  
Embryonic Induction ◽  
Cell Geometry ◽  
Signal Dampening

Detection and mapping of interactions between chromatin and the nuclear envelope in drosophila embryos

1995 ◽  
Vol 53 ◽  
pp. 764-765
Author(s):  
W.F. Marshall ◽  
A.F. Dernburg ◽  
B. Harmon ◽  
J.W. Sedat
Keyword(s):  
Nuclear Envelope ◽  
Chromatin Condensation ◽  
Three Dimensional ◽  
Physiological Role ◽  
Nuclear Surface ◽  
Intact Cells ◽  
Molecular Determinants ◽  
Surface Harmonic ◽  
Drosophila Embryos

Interactions between chromatin and nuclear envelope (NE) have been implicated in chromatin condensation, gene regulation, nuclear reassembly, and organization of chromosomes within the nucleus. To further investigate the physiological role played by such interactions, it will be necessary to determine which loci specifically interact with the nuclear envelope. This will not only facilitate identification of the molecular determinants of this interaction, but will also allow manipulation of the pattern of chromatin-NE interactions to probe possible functions. We have developed a microscopic approach to detect and map chromatin-NE interactions inside intact cells.Fluorescence in situ hybridization (FISH) is used to localize specific chromosomal regions within the nucleus of Drosophila embryos and anti-lamin immunofluorescence is used to detect the nuclear envelope. Widefield deconvolution microscopy is then used to obtain a three-dimensional image of the sample (Fig. 1). The nuclear surface is represented by a surface-harmonic expansion (Fig 2). A statistical test for association of the FISH spot with the surface is then performed.

Effects of Mg2+ on Chromatic Structure in Isolated Chicken Liver Nuclei

1990 ◽  
Vol 48 (3) ◽  
pp. 130-131
Author(s):  
Soichiro Arai ◽  
Yuh H. Nakanishi
Keyword(s):  
Chromatin Structure ◽  
Room Temperature ◽  
Osmium Tetroxide ◽  
Divalent Cations ◽  
Chromatin Condensation ◽  
Chicken Liver ◽  
Electron Microscopic ◽  
Razor Blade ◽  
Microscopic Studies ◽  
Liver Nuclei

Although many electron microscopic studies on extracted chromatin have provided considerable information on chromatin condensation induced by divalent cations, there is only a little literature available on the effects of divalent cations on chromatin structure in intact nuclei. In the present study, the effects of Mg2+ on chromatin structure in isolated chicken liver nuclei were examined over a wide concentration range of Mg2+ by scanning electron microscopy.Nuclei were prepared from chicken liver by the method of Chauveau et al. with some modifications. The nuclei were suspended in 25 mM triethanolamine chloride buffer (pH7.4) with 1 mM EDTA or in the buffer with concentrations of MgCl2 varying from 1 to 50 mM. After incubation for 1 min at 0°C, glutaraldehyde was added to 1.8% and the nuclei were fixed for 1 h at 4°C. The fixed nuclei were mixed with 15% gelatin solution warmed at about 40°C, and kept at room temperature until the mixture set. The gelatin containing the nuclei was fixed with 2% glutaraldehyde for 2-4 h, and cut into small blocks. The gelatin blocks were conductive-stained with 2% tannic acid and 2% osmium tetroxide, dehydrated in a graded series of ethanol, and freeze-cracked with a razor blade in liquid nitrogen.

Absence of temporal ordering of apoptotic features in heat-shock treated leukemia and lymphoma cell lines

1996 ◽  
Vol 54 ◽  
pp. 758-759
Author(s):  
D. W. Fairbain ◽  
M.D. Standing ◽  
K.L. O'Neill
Keyword(s):  
Heat Shock ◽  
Cell Lines ◽  
Chromatin Condensation ◽  
Membrane Integrity ◽  
Resistant Cell ◽  
Membrane Blebbing ◽  
Late Loss ◽  
Induced Apoptosis ◽  
Dying Cells ◽  
In Cells

Apoptosis is a genetically defined response to physiological stimuli that results in cellular suicide. Features common to apoptotic cells include chromatin condensation, oligonucleosomal DNA fragmentation, membrane blebbing, nuclear destruction, and late loss of ability to exclude vital dyes. These characteristics contrast markedly from pathological necrosis, in which membrane integrity loss is demonstrated early, and other features of apoptosis, which allow a non-inflammatory removal of dead and dying cells, are absent. Using heat shock-induced apoptosis as a model for examining stress response in cells, we undertook to categorize a variety of human leukemias and lymphomas with regard to their response to heat shock. We were also interested in determining whether a common temporal order was followed in cells dying by apoptosis. In addition, based on our previous results, we investigated whether increasing heat load resulted in increased apoptosis, with particular interest in relatively resistant cell lines, or whether the mode of death changed from apoptosis to necrosis.

Registered Report: Transcriptional Analysis of Savings Memory Suggests Forgetting Is Due to Retrieval Failure

2020 ◽  
Author(s):  
Robert Calin-Jageman ◽  
Irina Calin-Jageman ◽  
Tania Rosiles ◽  
Melissa Nguyen ◽  
Annette Garcia ◽  
...  
Keyword(s):  
Memory Trace ◽  
Aplysia Californica ◽  
Transcriptional Response ◽  
Transcriptional Analysis ◽  
Retrieval Failure ◽  
Initial Learning ◽  
Rigorous Test ◽  
Stage 1 ◽  
Induced Changes

[[This is a Stage 2 Registered Report manuscript now accepted for publication at eNeuro. The accepted Stage 1 manuscript is posted here: https://psyarxiv.com/s7dft, and the pre-registration for the project is available here (https://osf.io/fqh8j, 9/11/2019). A link to the final Stage 2 manuscript will be posted after peer review and publication.]] There is fundamental debate about the nature of forgetting: some have argued that it represents the decay of the memory trace, others that the memory trace persists but becomes inaccessible due to retrieval failure. These different accounts of forgetting lead to different predictions about savings memory, the rapid re-learning of seemingly forgotten information. If forgetting is due to decay, then savings requires re-encoding and should thus involve the same mechanisms as initial learning. If forgetting is due to retrieval failure, then savings should be mechanistically distinct from encoding. In this registered report we conducted a pre-registered and rigorous test between these accounts of forgetting. Specifically, we used microarray to characterize the transcriptional correlates of a new memory (1 day after training), a forgotten memory (8 days after training), and a savings memory (8 days after training but with a reminder on day 7 to evoke a long-term savings memory) for sensitization in Aplysia californica (n = 8 samples/group). We found that the re-activation of sensitization during savings does not involve a substantial transcriptional response. Thus, savings is transcriptionally distinct relative to a newer (1-day old) memory, with no co-regulated transcripts, negligible similarity in regulation-ranked ordering of transcripts, and a negligible correlation in training-induced changes in gene expression (r = .04 95% CI [-.12, .20]). Overall, our results suggest that forgetting of sensitization memory represents retrieval failure.

Sign in / Sign up

Export Citation Format

Share Document