86,870 research outputs found
How Polycomb-Mediated Cell Memory Deals With a Changing Environment
No full textCells and tissues are continuously exposed to a changing microenvironment, hence the necessity of a flexible modulation of gene expression that in complex organism have been achieved through specialized chromatin mechanisms. Chromatin-based cell memory enables cells to maintain their identity by fixing lineage specific transcriptional programs, ensuring their faithful transmission through cell division; in particular PcG-based memory system evolved to maintain the silenced state of developmental and cell cycle genes. In evolution the complexity of this system have increased, particularly in vertebrates, indicating combinatorial and dynamic properties of Polycomb proteins, in some cases even overflowing outside the cell nucleus. Therefore, their function may not be limited to the imposition of rigid states of genetic programs, but on the ability to recognize signals and allow plastic transcriptional changes in response to different stimuli. Here, we discuss the most novel PcG mediated memory functions in facing and responding to the challenges posed by a fluctuating environment
Lo sviluppo di risorse immateriali per l'internazionalizzazione: il ruolo dei consorzi export nei paesi in via di sviluppo
No full textIl paper analizza le problematiche associate allo sviluppo di risorse immateriali tramite consorzi export nelle PMI provenienti da paesi in via di sviluppo e orientate all’internazionalizzazione. La letteratura di riferimento è molto vasta, in quanto si colloca al crocevia degli studi su: i consorzi e, più in generale, le reti di imprese;i processi di sviluppo e d’internazionalizzazione delle PMI;i problemi connessi alla competitività e al management delle imprese localizzate nei paesi più poveri del mondo;le scelte strategiche, gli assetti, le strutture e i processi che favoriscono lo sviluppo di risorse immateriali (in particolare, capitale relazionale, competenze e conoscenze connesse all’internazionalizzazione, reputazione e immagine presso i clienti esteri).
Obiettivo del lavoro è analizzare se e in che misura i consorzi export contribuiscano ad accrescere la dotazione di risorse immateriali delle imprese partner, con riferimento soprattutto alle risorse maggiormente rilevanti ai fini dei processi d’internazionalizzazione. Oltre a valutare l’importanza dei consorzi a tale scopo, l’intento è anche quello d’indagare il processo di generazione, sviluppo e rafforzamento di tali risorse all’interno dei consorzi stessi
Small vessel vasculitis related to varicella-zoster virus after Pfizer-BioNTech COVID-19 vaccine
No full textChromosome Conformation Capture Followed by Genome-Wide Sequencing (Hi-C) in Drosophila Embryos
No full textThis protocol provides specific details on how to perform Hi-C, the genome-wide version of Chromosome Conformation Capture (3C) followed by high-throughput sequencing, in Drosophila embryos. Hi-C provides a genome-wide population-averaged snapshot of the 3D genome organization within nuclei. In Hi-C, formaldehyde-cross-linked chromatin is enzymatically digested using restriction enzymes; digested fragments are biotinylated and subjected to proximity ligation; ligated fragments are purified using streptavidin followed by paired-end sequencing. Hi-C allows the detection of higher order folding structures such as topologically associated domains (TADs) and active/inactive compartments (A/B compartments, respectively). Performing this assay in developing embryos gives the unique opportunity to investigate dynamic chromatin changes when 3D chromatin structure is established in embryogenesis
3d combo chrrna–dna–immunofish
No full textEpigenetic mechanisms govern the quality, the stability, and the responsiveness of transcriptional programs to the environment. This regulation is ensured via the concerted action of different players (transcription factors, “reader” and “writer” enzymes, histone marks, structural proteins, noncoding regulatory RNAs) that flow in the 3D organization of the genome. Indeed, nuclear architecture participates in the punctual and cell-type-specific regulation of transcription. Hence, the fine dissection of these mechanisms will allow a deeper understanding of the gene expression machinery. In this chapter, we propose a challenging imaging-based method to study the reciprocal interactions between chromatin-associated RNAs, genomic loci, and chromatin compartment with a procedure of 3D COMBO chrRNA–DNA–ImmunoFISH, specifically developed to preserve the nuclear integrity and topology of human primary T cells. We believe that our protocol will contribute to the improvement of epigenetic studies on the 3D nuclear structure of T cell subsets, possibly shedding light on the still hidden epigenetic players responsible for the great plasticity and functional diversification exerted by T cells
Can COVID-19 cause atypical forms of pityriasis rosea refractory to conventional therapies?
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