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Epigenetic silencing

Yuan Chen, Kai Leonie Schnitzler, Yunxia Ma, Miljana Nenkov, Bernhard Theis, Iver Petersen
Exploitation of autophagy might potentially improve therapeutic strategy. Here, we analyzed the protein expression of autophagy-associated genes including LC3A, LC3B, Beclin-1, p62, and Atg5 in 88-131 primary lung tumors by immunohistochemistry (IHC) on tissue-microarrays (TMAs). Additionally, the DNA methylation pattern of LC3A was investigated by bisulfite sequencing (BS) and methylation-specific-PCR (MSP). It turned out that the higher expression of LC3A protein was associated with adenocarcinoma compared to squamous cell carcinoma of lung ( p = 0...
2018: Disease Markers
Xiaohui Chen, Yujie Deng, Yi Shi, Weifeng Zhu, Yibin Cai, Chunwei Xu, Kunshou Zhu, Xiongwei Zheng, Gang Chen, Qi Xie, Guoxing Weng
Functional inactivation of human runt-related transcription factor 3 (RUNX3) through mutation or epigenetic silencing has been well-documented in many cancerous entities. In addition to gene mutation and promoter hypermethylation, cytoplasmic mislocalization has emerged as another major manifestation of RUNX3 dysfunction in malignancies including breast, colorectal and gastric cancers. The aim of the present study was to investigate whether patients with non-small cell lung cancer (NSCLC) and different RUNX3 expression patterns would have different overall survival (OS), and the associations between different patterns of clinicopathological parameters and clinical outcome...
April 2018: Oncology Letters
Yasunori Sasakura
Transgenesis is an indispensable method for elucidating the cellular and molecular mechanisms underlying biological phenomena. In Ciona, transgenic lines that have a transgene insertion in their genomes have been created. The transgenic lines are valuable because they express reporter genes in a nonmosaic manner. This nonmosaic manner allows us to accurately observe tissues and organs. The insertions of transgenes can destroy genes to create mutants. The insertional mutagenesis is a splendid method for investigating functions of genes...
2018: Advances in Experimental Medicine and Biology
Gigliola Zanghì, Shruthi S Vembar, Sebastian Baumgarten, Shuai Ding, Julien Guizetti, Jessica M Bryant, Denise Mattei, Anja T R Jensen, Laurent Rénia, Yun Shan Goh, Robert Sauerwein, Cornelus C Hermsen, Jean-François Franetich, Mallaury Bordessoulles, Olivier Silvie, Valérie Soulard, Olivier Scatton, Patty Chen, Salah Mecheri, Dominique Mazier, Artur Scherf
Heterochromatin plays a central role in the process of immune evasion, pathogenesis, and transmission of the malaria parasite Plasmodium falciparum during blood stage infection. Here, we use ChIP sequencing to demonstrate that sporozoites from mosquito salivary glands expand heterochromatin at subtelomeric regions to silence blood-stage-specific genes. Our data also revealed that heterochromatin enrichment is predictive of the transcription status of clonally variant genes members that mediate cytoadhesion in blood stage parasites...
March 13, 2018: Cell Reports
Tafadzwa Mlambo, Sandra Nitsch, Markus Hildenbeutel, Marianna Romito, Maximilian Müller, Claudia Bossen, Sven Diederichs, Tatjana I Cornu, Toni Cathomen, Claudio Mussolino
Targeted modulation of gene expression represents a valuable approach to understand the mechanisms governing gene regulation. In a therapeutic context, it can be exploited to selectively modify the aberrant expression of a disease-causing gene or to provide the target cells with a new function. Here, we have established a novel platform for achieving precision epigenome editing using designer epigenome modifiers (DEMs). DEMs combine in a single molecule a DNA binding domain based on highly specific transcription activator-like effectors (TALEs) and several effector domains capable of inducing DNA methylation and locally altering the chromatin structure to silence target gene expression...
March 10, 2018: Nucleic Acids Research
Guohong Wen, Huadong Wang, Zhaohui Zhong
BACKGROUND: Oral tumor is a heterogeneous group of tumors, in which it has several different histopathological and molecular features. Recently, genetic and epigenetic alterations are often detected in the development of oral cancer. Gene promoter hypermethylation leads to the silencing of cancer related genes without changes of genes sequence. To clarify the effect of RAS association domain family protein 1a (RASSF1A), retinoic acid receptor beta (RARβ), and E-cadherin (CDH1) promoter hypermethylation on the risk of oral cancer, we performed this meta-analysis...
March 2018: Medicine (Baltimore)
Mehrdad Zeinalian, Morteza Hashemzadeh-Chaleshtori, Rasoul Salehi, Mohammad Hassan Emami
Microsatellite instability (MSI) is a molecular hallmark for some colorectal cancers (CRCs) in which short tandem repeats are prone to mutations along with DNA sequences. It is due to DNA-mismatch-repair system deficiency because of a germline/somatic mutation in mismatch-repair (MMR) genes. The germline mutations lead to Lynch syndrome (LS) while epigenetic gene silencing results in sporadic CRC tumors. We discuss in our paper the most important clinical aspects of MSI testing in CRCs. We reviewed the most reliable relevant studies and clinical trials according to their high-quality methods, particularly within two recent decades...
2018: Advanced Biomedical Research
Kyuha Choi, Xiaohui Zhao, Andrew J Tock, Christophe Lambing, Charles J Underwood, Thomas J Hardcastle, Heïdi Serra, Juhyun Kim, Hyun Seob Cho, Jaeil Kim, Piotr A Ziolkowski, Nataliya E Yelina, Ildoo Hwang, Robert A Martienssen, Ian R Henderson
Meiotic recombination initiates from DNA double-strand breaks (DSBs) generated by SPO11 topoisomerase-like complexes. Meiotic DSB frequency varies extensively along eukaryotic chromosomes, with hotspots controlled by chromatin and DNA sequence. To map meiotic DSBs throughout a plant genome, we purified and sequenced Arabidopsis thaliana SPO11-1-oligonucleotides. SPO11-1-oligos are elevated in gene promoters, terminators, and introns, which is driven by AT-sequence richness that excludes nucleosomes and allows SPO11-1 access...
March 12, 2018: Genome Research
Charles J Underwood, Kyuha Choi, Christophe Lambing, Xiaohui Zhao, Heïdi Serra, Filipe Borges, Joe Simorowski, Evan Ernst, Yannick Jacob, Ian R Henderson, Robert A Martienssen
Eukaryotic centromeres contain the kinetochore, which connects chromosomes to the spindle allowing segregation. During meiosis, centromeres are suppressed for inter-homolog crossover, as recombination in these regions can cause chromosome missegregation and aneuploidy. Plant centromeres are surrounded by transposon-dense pericentromeric heterochromatin that is epigenetically silenced by histone 3 lysine 9 dimethylation (H3K9me2), and DNA methylation in CG and non-CG sequence contexts. However, the role of these chromatin modifications in control of meiotic recombination in the pericentromeres is not fully understood...
March 12, 2018: Genome Research
Marta Fontcuberta-PiSunyer, Sara Cervantes, Eulàlia Miquel, Sergio Mora-Castilla, Louise C Laurent, Angel Raya, Ramon Gomis, Rosa Gasa
Posttranscriptional modifications of histones constitute an epigenetic mechanism that is closely linked to both gene silencing and activation events. Trimethylation of Histone3 at lysine 27 (H3K27me3) is a repressive mark that associates with developmental gene regulation during differentiation programs. In the developing pancreas, expression of the transcription factor Neurogenin3 in multipotent progenitors initiates endocrine differentiation that culminates in the generation of all pancreatic islet cell lineages, including insulin-producing beta cells...
March 9, 2018: Biochimica et Biophysica Acta
Benjamin Pyles, Barbara J Bailus, Henriette O'Geen, David J Segal
The ability to activate or repress specific genes in the brain could have a tremendous impact for understanding and treating neurological disorders. Artificial transcription factors based on zinc finger, TALE, and CRISPR/Cas9 programmable DNA-binding platforms have been widely used to regulate the expression of specific genes in cultured cells, but their delivery into the brain represents a critical challenge to apply such tools in live animals. In previous work, we developed a purified, zinc finger-based artificial transcription factor that could be injected systemically, cross the blood-brain barrier, and alter expression of a specific gene in the brain of an adult mouse model of Angelman syndrome...
2018: Methods in Molecular Biology
Tafadzwa Mlambo, Marianna Romito, Tatjana I Cornu, Claudio Mussolino
The development of tools which allow for the precise alterations of the epigenetic landscape in desired genomic locations presents exciting possibilities toward further understanding how gene expression is regulated and opportunities to harness these properties for therapeutic purposes. In contrast to gene knockout strategies, targeted epigenome modifications, such as editing of DNA methylation, can mediate gene expression modulation without changing the genomic sequence. Thereby, in a therapeutic context, this strategy may offer a safer route as compared to gene disruption using designer nucleases that, to reach high efficiencies, relies on the occurrence of random mutations to inactivate the target gene...
2018: Methods in Molecular Biology
Pavel Bashtrykov, Albert Jeltsch
The discovery and adaptation of the CRISPR/Cas system for epigenome editing has allowed for a straightforward design of targeting modules which can direct epigenetic editors to virtually any genomic site. This advancement in DNA-targeting technology brings allele-specific epigenome editing into reach, a "super-specific" variation of epigenome editing whose goal is an alteration of chromatin marks at only one selected allele of the target genomic locus. This technology would be useful for the treatment of diseases caused by a mutant allele with a dominant effect, because allele-specific epigenome editing allows the specific silencing of the mutated allele leaving the healthy counterpart expressed...
2018: Methods in Molecular Biology
Shanshan Zhang, Dongfang Wang, Huajian Zhang, Megan I Skaggs, Alan Lloyd, Di Ran, Lingling An, Karen S Schumaker, Gary N Drews, Ramin Yadegari
Early endosperm development presents a unique system to uncover epigenetic regulatory mechanisms because the contributing maternal and paternal genomes possess differential epigenetic modifications. In Arabidopsis (Arabidopsis thaliana), the initiation of endosperm coenocytic growth upon fertilization and the transition to endosperm cellularization are regulated by the FERTILIZATION-INDEPENDENT SEED (FIS)-Polycomb Repressive Complex 2 (PRC2), a putative H3K27 methyltransferase. Here, we address the possible role of the FIS-PRC2 complex in regulating the type I MADS-box gene family, which has previously been shown to regulate early endosperm development...
March 9, 2018: Plant Physiology
Daniela A Grassi, Marie E Jönsson, Per Ludvik Brattås, Johan Jakobsson
TRIM28 is an epigenetic co-repressor protein that mediates transcriptional silencing. TRIM28 participates, together with the large family of Kruppel-associated box domain zinc finger proteins (KRAB-ZFP) transcription factors, in the repression of transposable elements (TE). Recent advances indicate that TRIM28-based repression of TEs occurs in the mammalian brain and may provide beneficial effects through the regulation of transcriptional networks. Here, we provide an overview of TRIM28-related functions, highlighting the role of controlling TEs in neural progenitor cells and discuss how this mechanism may have contributed to the evolution of the complex human brain...
March 6, 2018: Brain Research
Federica Marasca, Beatrice Bodega, Valerio Orlando
Cells 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...
March 9, 2018: BioEssays: News and Reviews in Molecular, Cellular and Developmental Biology
Chiara Antoniani, Vasco Meneghini, Annalisa Lattanzi, Tristan Felix, Oriana Romano, Elisa Magrin, Leslie Weber, Giulia Pavani, Sara El Hoss, Ryo Kurita, Yukio Nakamura, Thomas J Cradick, Ante S Lundberg, Matthew Porteus, Mario Amendola, Wassim El Nemer, Marina Cavazzana, Fulvio Mavilio, Annarita Miccio
Naturally occurring, large deletions in the β-globin locus result in hereditary persistence of fetal hemoglobin, a condition that mitigates the clinical severity of sickle-cell disease (SCD) and β-thalassemia. We designed a CRISPR/Cas9 strategy to disrupt a 13.6-kb genomic region encompassing the δ- and β-globin genes and a putative γ-δ intergenic fetal hemoglobin (HbF) silencer. Disruption of just the putative HbF silencer results in a mild increase in γ-globin expression, whereas deletion or inversion of a 13...
March 8, 2018: Blood
Arif Nurkanto, Ghulam Jeelani, Takehiro Yamamoto, Yoshiko Naito, Takako Hishiki, Mihoko Mori, Makoto Suematsu, Kazuro Shiomi, Tetsuo Hashimoto, Tomoyoshi Nozaki
The Coenzyme A (CoA), as a cofactor involved in >100 metabolic reactions, is essential to the basic biochemistry of life. Here, we investigated the CoA biosynthetic pathway of Entamoeba histolytica (E. histolytica), an enteric protozoan parasite responsible for human amebiasis. We identified four key enzymes involved in the CoA pathway: pantothenate kinase (PanK, EC, bifunctional phosphopantothenate-cysteine ligase/decarboxylase (PPCS-PPCDC), phosphopantetheine adenylyltransferase (PPAT) and dephospho-CoA kinase (DPCK)...
March 1, 2018: International Journal for Parasitology, Drugs and Drug Resistance
Dalibor Miklík, Filip Šenigl, Jiří Hejnar
Individual groups of retroviruses and retroviral vectors differ in their integration site preference and interaction with the host genome. Hence, immediately after infection genome-wide distribution of integrated proviruses is non-random. During long-term in vitro or persistent in vivo infection, the genomic position and chromatin environment of the provirus affects its transcriptional activity. Thus, a selection of long-term stably expressed proviruses and elimination of proviruses, which have been gradually silenced by epigenetic mechanisms, helps in the identification of genomic compartments permissive for proviral transcription...
March 8, 2018: Viruses
Sk Abdul Amin, Nilanjan Adhikari, Tarun Jha
Histone deacetylase inhibitors (HDACIs) have a paramount importance in the acetylation process of histone and non-histone proteins that are crucial players in the cellular epigenetic modifications. HDACIs exert effective antiproliferation through DNA repairing, cell cycle arrest, apoptosis induction and alteration of genetic expression. HDAC8 is one of the crucial HDACs, affects the epigenetic gene silencing process and cancer progression. Hence, HDAC8 is one of the key cancer targets among class I HDACs that may be effectively blocked as a benchmark therapy to combat malignancy...
March 4, 2018: Pharmacological Research: the Official Journal of the Italian Pharmacological Society
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