Schlagwort: Altern
Textile Innovationen für die ambulante Gesundheitsversorgung
Initiative für neues Gesundheitsverständnis
Forschungsprojekt der Universität Paderborn zeigt Effekte von Exergames auf Körper und Gehirn bei älteren Menschen
Wissenschaftler*innen der Universität Paderborn haben deren Einfluss, insbesondere auf die Leistungsfähigkeit älterer Menschen, nun auch wissenschaftlich bestätigt.
Wechsel von Fasten und Essen wichtig für gesundes Altern: Genetischer Kniff rettet alte Fische aus der Dauerfastenfalle
Kognitives Altern und Persönlichkeit: Kann Offenheit für neue Erfahrungen das Gedächtnis schützen?
DIfE-Jahresbericht 2021-2022 erschienen
Können wir unseren Zellen helfen gesund zu altern?
Studie: Einnahme von Taurin verzögert Alterung im Tierversuch
Blick ins Herz der zellulären Müllabfuhr
Kälte fördert gesundes Altern
Neuartige Methode ermöglicht Genstudien zur Funktion und zu Erkrankungen der Darmschleimhaut
Fitnessprogramm für Blutstammzellen – TAZ-Protein schützt vor alternsbedingtem Funktionsverlust
Dornröschen im Eiswürfel: Wie Bärtierchen Eiseskälte überdauern
Altern vorprogrammiert – Gen-gesteuertes Wachstum in der Jugend lässt Blutstammzellen altern
Glykierung im Körper – Auslöser für Proteinfehlfunktionen im Alter und bei altersassoziierten Erkrankungen
Medikamente gegen das Altern: Die Jungbrunnen-Formel
Schnelleres Altern durch Stress
Wie Zwillingsstudien neue Erkenntnisse über Einfluss von Long-COVID auf das Altern liefern – Vortrag von Claire Steves
A global assessment of cancer genomic alterations in epigenetic mechanisms
Muhammad A Shah, Emily L Denton, Cheryl H Arrowsmith, Mathieu Lupien and Matthieu Schapira
Abstract
Background
The notion that epigenetic mechanisms may be central to cancer initiation and progression is supported by recent next-generation sequencing efforts revealing that genes involved in chromatin-mediated signaling are recurrently mutated in cancer patients.
Results
Here, we analyze mutational and transcriptional profiles from TCGA and the ICGC across a collection 441 chromatin factors and histones. Chromatin factors essential for rapid replication are frequently overexpressed, and those that maintain genome stability frequently mutated. We identify novel mutation hotspots such as K36M in histone H3.1, and uncover a general trend in which transcriptional profiles and somatic mutations in tumor samples favor increased transcriptionally repressive histone methylation, and defective chromatin remodeling.
Conclusions
This unbiased approach confirms previously published data, uncovers novel cancer-associated aberrations targeting epigenetic mechanisms, and justifies continued monitoring of chromatin-related alterations as a class, as more cancer types and distinct cancer stages are represented in cancer genomics data repositories.
Continue reading „A global assessment of cancer genomic alterations in epigenetic mechanisms“ →
Three-dimensional super-resolution microscopy of the inactive X chromosome territory reveals a collapse of its active nuclear compartment harboring distinct Xist RNA foci
Daniel Smeets, Yolanda Markaki, Volker J Schmid, Felix Kraus, Anna Tattermusch, Andrea Cerase, Michael Sterr, Susanne Fiedler, Justin Demmerle, Jens Popken, Heinrich Leonhardt, Neil Brockdorff, Thomas Cremer1, Lothar Schermelleh and Marion Cremer
Abstract
Background
A Xist RNA decorated Barr body is the structural hallmark of the compacted inactive X territory in female mammals. Using super-resolution three-dimensional structured illumination microscopy (3D-SIM) and quantitative image analysis, we compared its ultrastructure with active chromosome territories (CTs) in human and mouse somatic cells, and explored the spatio-temporal process of Barr body formation at onset of inactivation in early differentiating mouse embryonic stem cells (ESCs).
Results
We demonstrate that all CTs are composed of structurally linked chromatin domain clusters (CDCs). In active CTs the periphery of CDCs harbors low-density chromatin enriched with transcriptionally competent markers, called the perichromatin region (PR). The PR borders on a contiguous channel system, the interchromatin compartment (IC), which starts at nuclear pores and pervades CTs. We propose that the PR and macromolecular complexes in IC channels together form the transcriptionally permissive active nuclear compartment (ANC). The Barr body differs from active CTs by a partially collapsed ANC with CDCs coming significantly closer together, although a rudimentary IC channel system connected to nuclear pores is maintained. Distinct Xist RNA foci, closely adjacent to the nuclear matrix scaffold attachment factor-A (SAF-A) localize throughout Xi along the rudimentary ANC. In early differentiating ESCs initial Xist RNA spreading precedes Barr body formation, which occurs concurrent with the subsequent exclusion of RNA polymerase II (RNAP II). Induction of a transgenic autosomal Xist RNA in a male ESC triggers the formation of an ‘autosomal Barr body’ with less compacted chromatin and incomplete RNAP II exclusion.
Conclusions
3D-SIM provides experimental evidence for profound differences between the functional architecture of transcriptionally active CTs and the Barr body. Basic structural features of CT organization such as CDCs and IC channels are however still recognized, arguing against a uniform compaction of the Barr body at the nucleosome level. The localization of distinct Xist RNA foci at boundaries of the rudimentary ANC may be considered as snap-shots of a dynamic interaction with silenced genes. Enrichment of SAF-A within Xi territories and its close spatial association with Xist RNA suggests their cooperative function for structural organization of Xi.
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