keyword
MENU ▼
Read by QxMD icon Read
search

Repressed memories

keyword
https://www.readbyqxmd.com/read/29212661/disruption-of-an-rna-binding-hinge-region-abolishes-lhp1-mediated-epigenetic-repression
#1
Scott Berry, Stefanie Rosa, Martin Howard, Marc Bühler, Caroline Dean
Epigenetic maintenance of gene repression is essential for development. Polycomb complexes are central to this memory, but many aspects of the underlying mechanism remain unclear. LIKE HETEROCHROMATIN PROTEIN 1 (LHP1) binds Polycomb-deposited H3K27me3 and is required for repression of many Polycomb target genes in Arabidopsis Here we show that LHP1 binds RNA in vitro through the intrinsically disordered hinge region. By independently perturbing the RNA-binding hinge region and H3K27me3 (trimethylation of histone H3 at Lys27) recognition, we found that both facilitate LHP1 localization and H3K27me3 maintenance...
December 6, 2017: Genes & Development
https://www.readbyqxmd.com/read/29190361/shaping-epigenetic-memory-via-genomic-bookmarking
#2
Davide Michieletto, Michael Chiang, Davide Colì, Argyris Papantonis, Enzo Orlandini, Peter R Cook, Davide Marenduzzo
Reconciling the stability of epigenetic patterns with the rapid turnover of histone modifications and their adaptability to external stimuli is an outstanding challenge. Here, we propose a new biophysical mechanism that can establish and maintain robust yet plastic epigenetic domains via genomic bookmarking (GBM). We model chromatin as a recolourable polymer whose segments bear non-permanent histone marks (or colours) which can be modified by 'writer' proteins. The three-dimensional chromatin organisation is mediated by protein bridges, or 'readers', such as Polycomb Repressive Complexes and Transcription Factors...
November 28, 2017: Nucleic Acids Research
https://www.readbyqxmd.com/read/29178433/triptolide-inhibits-donor-specific-antibody-production-and-attenuates-mixed-antibody-mediated-renal-allograft-injury
#3
Daqiang Zhao, Siwen Li, Tao Liao, Yuan Wei, Mingyu Liu, Fei Han, Zihuan Luo, Xiaonan Liu, Qiquan Sun
Donor specific antibodies (DSAs) are major mediators of renal allograft injury, and strategies to inhibit DSA are important in promoting long term graft survival. Triptolide exhibits a wide spectrum of anti-inflammatory and immuno- suppressive activities, and in autoimmune diseases it inhibits autoantibody levels. In this study, we investigated the suppressive role of triptolide in the generation of donor specific antibodies in transplant recipients. We found that triptolide treatment of skin allograft recipients in the mouse significantly suppressed the development of circulating anti-donor specific IgG and effectively alleviated DSAs-mediated renal allograft injury, which led to prolonged allograft survival...
November 27, 2017: American Journal of Transplantation
https://www.readbyqxmd.com/read/29155979/epigenetic-editing-of-the-dlg4-psd95-gene-improves-cognition-in-aged-and-alzheimer-s-disease-mice
#4
Fernando J Bustos, Estibaliz Ampuero, Nur Jury, Rodrigo Aguilar, Fahimeh Falahi, Jorge Toledo, Juan Ahumada, Jaclyn Lata, Paula Cubillos, Berta Henríquez, Miguel V Guerra, Jimmy Stehberg, Rachael L Neve, Nibaldo C Inestrosa, Ursula Wyneken, Marco Fuenzalida, Steffen Härtel, Miguel Sena-Esteves, Lorena Varela-Nallar, Marianne G Rots, Martin Montecino, Brigitte van Zundert
The Dlg4 gene encodes for post-synaptic density protein 95 (PSD95), a major synaptic protein that clusters glutamate receptors and is critical for plasticity. PSD95 levels are diminished in ageing and neurodegenerative disorders, including Alzheimer's disease and Huntington's disease. The epigenetic mechanisms that (dys)regulate transcription of Dlg4/PSD95, or other plasticity genes, are largely unknown, limiting the development of targeted epigenome therapy. We analysed the Dlg4/PSD95 epigenetic landscape in hippocampal tissue and designed a Dlg4/PSD95 gene-targeting strategy: a Dlg4/PSD95 zinc finger DNA-binding domain was engineered and fused to effector domains to either repress (G9a, Suvdel76, SKD) or activate (VP64) transcription, generating artificial transcription factors or epigenetic editors (methylating H3K9)...
November 16, 2017: Brain: a Journal of Neurology
https://www.readbyqxmd.com/read/29153325/genetic-and-epigenetic-strategies-potentiate-gal4-activation-to-enhance-fitness-in-recently-diverged-yeast-species
#5
Varun Sood, Jason H Brickner
Certain genes show more rapid reactivation for several generations following repression, a conserved phenomenon called epigenetic transcriptional memory. Following previous growth in galactose, GAL gene transcriptional memory confers a strong fitness benefit in Saccharomyces cerevisiae adapting to growth in galactose for up to 8 generations. A genetic screen for mutants defective for GAL gene memory revealed new insights into the molecular mechanism, adaptive consequences, and evolutionary history of memory...
November 9, 2017: Current Biology: CB
https://www.readbyqxmd.com/read/29122005/memories-of-paternal-relations-are-associated-with-coping-and-defense-mechanisms-in-breast-cancer-patients-an-observational-study
#6
Chiara Renzi, Giada Perinel, Paola Arnaboldi, Sara Gandini, Valeria Vadilonga, Nicole Rotmensz, Angela Tagini, Florence Didier, Gabriella Pravettoni
BACKGROUND: Breast cancer diagnosis and treatment represent stressful events that demand emotional adjustment, thus recruiting coping strategies and defense mechanisms. As parental relations were shown to influence emotion regulation patterns and adaptive processes in adulthood, the present study investigated whether they are specifically associated to coping and defense mechanisms in patients with breast cancer. METHODS: One hundred and ten women hospitalized for breast cancer surgery were administered questionnaires assessing coping with cancer, defense mechanisms, and memories of parental bonding in childhood...
November 9, 2017: BMC Psychology
https://www.readbyqxmd.com/read/29114037/reducing-eif4e-eif4g-interactions-restores-the-balance-between-protein-synthesis-and-actin-dynamics-in-fragile-x-syndrome-model-mice
#7
Emanuela Santini, Thu N Huynh, Francesco Longo, So Yeon Koo, Edward Mojica, Laura D'Andrea, Claudia Bagni, Eric Klann
Fragile X syndrome (FXS) is the most common form of inherited intellectual disability and autism spectrum disorder. FXS is caused by silencing of the FMR1 gene, which encodes fragile X mental retardation protein (FMRP), an mRNA-binding protein that represses the translation of its target mRNAs. One mechanism by which FMRP represses translation is through its association with cytoplasmic FMRP-interacting protein 1 (CYFIP1), which subsequently sequesters and inhibits eukaryotic initiation factor 4E (eIF4E). CYFIP1 shuttles between the FMRP-eIF4E complex and the Rac1-Wave regulatory complex, thereby connecting translational regulation to actin dynamics and dendritic spine morphology, which are dysregulated in FXS model mice that lack FMRP...
November 7, 2017: Science Signaling
https://www.readbyqxmd.com/read/29101321/contribution-of-epigenetic-landscapes-and-transcription-factors-to-x-chromosome-reactivation-in-the-inner-cell-mass
#8
Maud Borensztein, Ikuhiro Okamoto, Laurène Syx, Guillaume Guilbaud, Christel Picard, Katia Ancelin, Rafael Galupa, Patricia Diabangouaya, Nicolas Servant, Emmanuel Barillot, Azim Surani, Mitinori Saitou, Chong-Jian Chen, Konstantinos Anastassiadis, Edith Heard
X-chromosome inactivation is established during early development. In mice, transcriptional repression of the paternal X-chromosome (Xp) and enrichment in epigenetic marks such as H3K27me3 is achieved by the early blastocyst stage. X-chromosome inactivation is then reversed in the inner cell mass. The mechanisms underlying Xp reactivation remain enigmatic. Using in vivo single-cell approaches (allele-specific RNAseq, nascent RNA-fluorescent in situ hybridization and immunofluorescence), we show here that different genes are reactivated at different stages, with more slowly reactivated genes tending to be enriched in H3meK27...
November 3, 2017: Nature Communications
https://www.readbyqxmd.com/read/29089052/epigenetic-control-of-epilepsy-target-genes-contributes-to-a-cellular-memory-of-epileptogenesis-in-cultured-rat-hippocampal-neurons
#9
K Kiese, J Jablonski, J Hackenbracht, J K Wrosch, T W Groemer, J Kornhuber, I Blümcke, K Kobow
Hypersynchronous neuronal excitation manifests clinically as seizure (ictogenesis), and may recur spontaneously and repetitively after a variable latency period (epileptogenesis). Despite tremendous research efforts to describe molecular pathways and signatures of epileptogenesis, molecular pathomechanisms leading to chronic epilepsy remain to be clarified. We hypothesized that epigenetic modifications may form the basis for a cellular memory of epileptogenesis, and used a primary neuronal cell culture model of the rat hippocampus to study the translation of massive neuronal excitation into persisting changes of epigenetic signatures and pro-epileptogenic target gene expression...
October 31, 2017: Acta Neuropathologica Communications
https://www.readbyqxmd.com/read/29081819/cognitive-function-of-artemisia-argyi-h-fermented-by-monascus-purpureus-under-tmt-induced-learning-and-memory-deficits-in-icr-mice
#10
Jin Yong Kang, Du Sang Lee, Seon Kyeong Park, Jeong Su Ha, Jong Min Kim, Gi Jeong Ha, Weon Taek Seo, Ho Jin Heo
The cognitive effect of Artemisia argyi H. under liquid-state fermentation by Monascus purpureus (AAFM), which has cellular antioxidant activity and neuronal cell viability, on trimethyltin- (TMT-) induced learning and memory impairment in Institute of Cancer Research (ICR) mice was confirmed. Tests were conducted to determine the neuroprotective effects against H2O2-induced oxidative stress, and the results showed that AAFM has protective effects through the repression of mitochondrial injury and cellular membrane damage against H2O2-induced neurotoxicity...
2017: Evidence-based Complementary and Alternative Medicine: ECAM
https://www.readbyqxmd.com/read/29034500/how-communication-between-nucleosomes-enables-spreading-and-epigenetic-memory-of-histone-modifications
#11
REVIEW
Fabian Erdel
Nucleosomes "talk" to each other about their modification state to form extended domains of modified histones independently of the underlying DNA sequence. At the same time, DNA elements promote modification of nucleosomes in their vicinity. How do these site-specific and histone-based activities act together to regulate spreading of histone modifications along the genome? How do they enable epigenetic memory to preserve cell identity? Many models for the dynamics of repressive histone modifications emphasize the role of strong positive feedback loops, which reinforce histone modifications by recruiting histone modifiers to preexisting modifications...
October 16, 2017: BioEssays: News and Reviews in Molecular, Cellular and Developmental Biology
https://www.readbyqxmd.com/read/28970783/the-histone-h3k27-demethylase-utx-regulates-synaptic-plasticity-and-cognitive-behaviors-in-mice
#12
Gang-Bin Tang, Yu-Qiang Zeng, Pei-Pei Liu, Ting-Wei Mi, Shuang-Feng Zhang, Shang-Kun Dai, Qing-Yuan Tang, Lin Yang, Ya-Jie Xu, Hai-Liang Yan, Hong-Zhen Du, Zhao-Qian Teng, Feng-Quan Zhou, Chang-Mei Liu
Histone demethylase UTX mediates removal of repressive trimethylation of histone H3 lysine 27 (H3K27me3) to establish a mechanistic switch to activate large sets of genes. Mutation of Utx has recently been shown to be associated with Kabuki syndrome, a rare congenital anomaly syndrome with dementia. However, its biological function in the brain is largely unknown. Here, we observe that deletion of Utx results in increased anxiety-like behaviors and impaired spatial learning and memory in mice. Loss of Utx in the hippocampus leads to reduced long-term potentiation and amplitude of miniature excitatory postsynaptic current, aberrant dendrite development and defective synapse formation...
2017: Frontiers in Molecular Neuroscience
https://www.readbyqxmd.com/read/28959219/investigating-behavioral-and-psychophysiological-reactions-to-conflict-related-and-individualized-stimuli-as-potential-correlates-of-repression
#13
Henrik Kessler, Anna Christine Schmidt, Oliver Hildenbrand, Daniela Scharf, Aram Kehyayan, Nikolai Axmacher
Background: Repression is considered as a central defense mechanism in psychodynamic theory. It refers to the process by which "unbearable" mental contents (e.g., those related to internal conflicts) are kept out of consciousness. The process of repression is probably closely related to concepts of emotion regulation derived from a different theoretical background. This relationship is particularly relevant because it relates repression to current research in the affective neurosciences as well as to experimental studies on emotion regulation...
2017: Frontiers in Psychology
https://www.readbyqxmd.com/read/28950098/no-winter-lasts-forever-polycomb-complexes-convert-epigenetic-memory-of-cold-into-flowering
#14
Jafar Sharif, Haruhiko Koseki
Two recent papers in Science (Jiang and Berger, 2017 and Yang et al., 2017) reveal that an epigenetic mechanism, mediated by polycomb repressor complex 2 (PRC2), induces flowering after prolonged cold. This repression is biphasic, requiring nucleation and propagation; and, strikingly, appears to be intrinsically linked with DNA replication.
September 25, 2017: Developmental Cell
https://www.readbyqxmd.com/read/28939403/piperine-restores-streptozotocin-induced-cognitive-impairments-insights-into-oxidative-balance-in-cerebrospinal-fluid-and-hippocampus
#15
Mohsen Khalili-Fomeshi, Mohammad Golparvar Azizi, Mohammad Reza Esmaeili, Mohammad Gol, Sohrab Kazemi, Manouchehr Ashrafpour, Ali Akbar Moghadamnia, Soheila Hosseinzadeh
Piperine has been shown to have antioxidant activity and a cognitive-enhancing effect following long-term oral administration. In a comparative study of memantine, the current investigation threw light on the cognitive benefits of piperine. Lipid peroxidation and the ferric reducing antioxidant power (FRAP) of cerebrospinal fluid (CSF) and hippocampus in streptozotocin (STZ)-induced experimental dementia of the Alzheimer's type was measured. After reaching a criterion in a memory test, STZ-induced rats received piperine [2...
September 20, 2017: Behavioural Brain Research
https://www.readbyqxmd.com/read/28938122/genome-regulation-by-polycomb-and-trithorax-70-years-and-counting
#16
REVIEW
Bernd Schuettengruber, Henri-Marc Bourbon, Luciano Di Croce, Giacomo Cavalli
Polycomb (PcG) and Trithorax (TrxG) group proteins are evolutionarily conserved chromatin-modifying factors originally identified as part of an epigenetic cellular memory system that maintains repressed or active gene expression states. Recently, they have been shown to globally control a plethora of cellular processes. This functional diversity is achieved by their ability to regulate chromatin at multiple levels, ranging from modifying local chromatin structure to orchestrating the three-dimensional organization of the genome...
September 21, 2017: Cell
https://www.readbyqxmd.com/read/28910569/hierarchical-recruitment-of-polycomb-complexes-revisited
#17
Eshagh Dorafshan, Tatyana G Kahn, Yuri B Schwartz
Polycomb Group (PcG) proteins epigenetically repress key developmental genes and thereby control alternative cell fates. PcG proteins act as complexes that can modify histones and these histone modifications play a role in transmitting the "memory" of the repressed state as cells divide. Here we consider mainstream models that link histone modifications to hierarchical recruitment of PcG complexes and compare them to results of a direct test of interdependence between PcG complexes for recruitment to Drosophila genes...
September 14, 2017: Nucleus
https://www.readbyqxmd.com/read/28904110/the-chromatin-accessibility-signature-of-human-immune-aging-stems-from-cd8-t-cells
#18
Duygu Ucar, Eladio J Márquez, Cheng-Han Chung, Radu Marches, Robert J Rossi, Asli Uyar, Te-Chia Wu, Joshy George, Michael L Stitzel, A Karolina Palucka, George A Kuchel, Jacques Banchereau
Aging is linked to deficiencies in immune responses and increased systemic inflammation. To unravel the regulatory programs behind these changes, we applied systems immunology approaches and profiled chromatin accessibility and the transcriptome in PBMCs and purified monocytes, B cells, and T cells. Analysis of samples from 77 young and elderly donors revealed a novel and robust aging signature in PBMCs, with simultaneous systematic chromatin closing at promoters and enhancers associated with T cell signaling and a potentially stochastic chromatin opening mostly found at quiescent and repressed sites...
October 2, 2017: Journal of Experimental Medicine
https://www.readbyqxmd.com/read/28903040/mir-150-regulates-memory-cd8%C3%A2-t-cell-differentiation-via-c-myb
#19
Zeyu Chen, Erietta Stelekati, Makoto Kurachi, Sixiang Yu, Zhangying Cai, Sasikanth Manne, Omar Khan, Xiaolu Yang, E John Wherry
MicroRNAs play an important role in T cell responses. However, how microRNAs regulate CD8 T cell memory remains poorly defined. Here, we found that miR-150 negatively regulates CD8 T cell memory in vivo. Genetic deletion of miR-150 disrupted the balance between memory precursor and terminal effector CD8 T cells following acute viral infection. Moreover, miR-150-deficient memory CD8 T cells were more protective upon rechallenge. A key circuit whereby miR-150 repressed memory CD8 T cell development through the transcription factor c-Myb was identified...
September 12, 2017: Cell Reports
https://www.readbyqxmd.com/read/28835928/impaired-dna-replication-derepresses-chromatin-and-generates-a-transgenerationally-inherited-epigenetic-memory
#20
Adam Klosin, Kadri Reis, Cristina Hidalgo-Carcedo, Eduard Casas, Tanya Vavouri, Ben Lehner
Impaired DNA replication is a hallmark of cancer and a cause of genomic instability. We report that, in addition to causing genetic change, impaired DNA replication during embryonic development can have major epigenetic consequences for a genome. In a genome-wide screen, we identified impaired DNA replication as a cause of increased expression from a repressed transgene in Caenorhabditis elegans. The acquired expression state behaved as an "epiallele," being inherited for multiple generations before fully resetting...
August 2017: Science Advances
keyword
keyword
11705
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"