keyword
MENU ▼
Read by QxMD icon Read
search

Heterochromatin

keyword
https://www.readbyqxmd.com/read/28212444/sumo-modification-of-a-heterochromatin-histone-demethylase-jmjd2a-enables-viral-gene-transactivation-and-viral-replication
#1
Wan-Shan Yang, Mel Campbell, Pei-Ching Chang
Small ubiquitin-like modifier (SUMO) modification of chromatin has profound effects on transcription regulation. By using Kaposi's sarcoma associated herpesvirus (KSHV) as a model, we recently demonstrated that epigenetic modification of viral chromatin by SUMO-2/3 is involved in regulating gene expression and viral reactivation. However, how this modification orchestrates transcription reprogramming through targeting histone modifying enzymes remains largely unknown. Here we show that JMJD2A, the first identified Jumonji C domain-containing histone demethylase, is the histone demethylase responsible for SUMO-2/3 enrichment on the KSHV genome during viral reactivation...
February 17, 2017: PLoS Pathogens
https://www.readbyqxmd.com/read/28199849/quantitative-flim-fret-microscopy-to-monitor-nanoscale-chromatin-compaction-in%C3%A2-vivo-reveals-structural-roles-of-condensin-complexes
#2
David Llères, Aymeric P Bailly, Aurélien Perrin, David G Norman, Dimitris P Xirodimas, Robert Feil
How metazoan genomes are structured at the nanoscale in living cells and tissues remains unknown. Here, we adapted a quantitative FRET (Förster resonance energy transfer)-based fluorescence lifetime imaging microscopy (FLIM) approach to assay nanoscale chromatin compaction in living organisms. Caenorhabditis elegans was chosen as a model system. By measuring FRET between histone-tagged fluorescent proteins, we visualized distinct chromosomal regions and quantified the different levels of nanoscale compaction in meiotic cells...
February 14, 2017: Cell Reports
https://www.readbyqxmd.com/read/28199302/untimely-expression-of-gametogenic-genes-in-vegetative-cells-causes-uniparental-disomy
#3
H Diego Folco, Venkata R Chalamcharla, Tomoyasu Sugiyama, Gobi Thillainadesan, Martin Zofall, Vanivilasini Balachandran, Jothy Dhakshnamoorthy, Takeshi Mizuguchi, Shiv I S Grewal
Uniparental disomy (UPD), in which an individual contains a pair of homologous chromosomes originating from only one parent, is a frequent phenomenon that is linked to congenital disorders and various cancers. UPD is thought to result mostly from pre- or post-zygotic chromosome missegregation. However, the factors that drive UPD remain unknown. Here we use the fission yeast Schizosaccharomyces pombe as a model to investigate UPD, and show that defects in the RNA interference (RNAi) machinery or in the YTH domain-containing RNA elimination factor Mmi1 cause high levels of UPD in vegetative diploid cells...
February 15, 2017: Nature
https://www.readbyqxmd.com/read/28197915/the-role-of-sumoylation-in-senescence
#4
Lyndee L Scurr, Sebastian Haferkamp, Helen Rizos
Cellular senescence is a program initiated by many stress signals including aberrant activation of oncogenes, DNA damage, oxidative lesions and telomere attrition. Once engaged senescence irreversibly limits cellular proliferation and potently prevents tumor formation in vivo. The precise mechanisms driving the onset of senescence are still not completely defined, although the pRb and p53 tumor suppressor pathways converge with the SUMO cascade to regulate cellular senescence. Sumoylation translocates p53 to PML nuclear bodies where it can co-operate with many sumoylated co-factors in a program that activates pRb and favors senescence...
2017: Advances in Experimental Medicine and Biology
https://www.readbyqxmd.com/read/28197913/wrestling-with-chromosomes-the-roles-of-sumo-during-meiosis
#5
Amanda C Nottke, Hyun-Min Kim, Monica P Colaiácovo
Meiosis is a specialized form of cell division required for the formation of haploid gametes and therefore is essential for successful sexual reproduction. Various steps are exquisitely coordinated to ensure accurate chromosome segregation during meiosis, thereby promoting the formation of haploid gametes from diploid cells. Recent studies are demonstrating that an important form of regulation during meiosis is exerted by the post-translational protein modification known as sumoylation. Here, we review and discuss the various critical steps of meiosis in which SUMO-mediated regulation has been implicated thus far...
2017: Advances in Experimental Medicine and Biology
https://www.readbyqxmd.com/read/28193906/cbx3-promotes-colon-cancer-cell-proliferation-by-cdk6-kinase-independent-function-during-cell-cycle
#6
Yao Fan, Haiping Li, Xiaolong Liang, Zheng Xiang
Heterochromatin protein 1γ (CBX3) links histone methylation marks to transcriptional silence, DNA repair and RNA splicing, but a role for CBX3 in cancer remains largely unknown. In this study, we show that CBX3 in colon cancer cells promotes the progression of the cell cycle and proliferation in vitro and in vivo. Cell cycle (G1 phase to S phase) related gene CDK6 and p21 were further identified as targets of CBX3. In addition, we found that enhancing CDK6 suppresses cell proliferation by upregulating inhibitor p21 in the absence of CBX3, and this function is independent of the kinase activity of CDK6...
February 10, 2017: Oncotarget
https://www.readbyqxmd.com/read/28193737/exogenous-transposable-elements-circumvent-identity-based-silencing-permitting-the-dissection-of-expression-dependent-silencing
#7
Dalen Fultz, R Keith Slotkin
The propagation of epigenetic marks has received a great deal of attention, yet the initiation of epigenetic silencing of a new transgene, virus, or transposable element (TE) remains enigmatic. The overlapping and simultaneous function of multiple silencing mechanisms has obscured this area of investigation. Here, we have revealed two broad mechanisms that can initiate silencing independently: identity-based and expression-dependent silencing. We found that identity-based silencing is targeted by 21-22 or 24 nucleotide small interfering RNAs (siRNAs) generated from previously silenced regions of the genome...
February 13, 2017: Plant Cell
https://www.readbyqxmd.com/read/28192063/karyotype-diversity-in-doradidae-siluriformes-doradoidea-and-presence-of-the-heteromorphic-zz-zw-sex-chromosome-system-in-the-family
#8
Fábio Hiroshi Takagui, Lucas Ferreira de Moura, Daniela Cristina Ferreira, Liano Centofante, Carla de Andrade Vitorino, Vanessa Bueno, Vladimir Pavan Margarido, Paulo Cesar Venere
Karyotypes and other chromosomal markers as revealed by conventional and molecular cytogenetic protocols in four species of the catfish family Doradidae from the Araguaia-Tocantins river basin, namely Hassar wilderi, Leptodoras cataniae, Tenellus leporhinus and Tenellus trimaculatus were examined. All species had diploid chromosome number 2n = 58 and karyotypes dominated by biarmed chromosomes, simple NOR phenotype, that is, one chromosome pair bearing this site in terminal position, but some differences in karyotypes and distribution of constitutive heterochromatin, position of rDNA sites...
February 13, 2017: Zebrafish
https://www.readbyqxmd.com/read/28190810/visualization-of-the-spatial-arrangement-of-nuclear-organization-using-three-dimensional-fluorescence-in-situ-hybridization-in-early-mouse-embryos-a-new-easi-fish-chamber-glass-for-mammalian-embryos
#9
Masataka Nakaya, Hideyuki Tanabe, Shingo Takamatsu, Misaki Hosokawa, Tasuku Mitani
The fertilized oocyte begins cleavage, leading to zygotic gene activation (ZGA), which re-activates the resting genome to acquire totipotency. In this process, genomic function is regulated by the dynamic structural conversion in the nucleus. Indeed, a considerable number of genes that are essential for embryonic development are located near the pericentromeric regions, wherein the heterochromatin is formed. These genes are repressed transcriptionally in somatic cells. Three-dimensional fluorescence in situ hybridization (3D-FISH) enables the visualization of the intranuclear spatial arrangement, such as gene loci, chromosomal domains, and chromosome territories (CTs)...
February 11, 2017: Journal of Reproduction and Development
https://www.readbyqxmd.com/read/28188183/variants-of-the-sir4-coiled-coil-domain-improve-binding-to-sir3-for-heterochromatin-formation-in-saccharomyces-cerevisiae
#10
Anke Samel, Adam Rudner, Ann E Ehrenhofer-Murray
Heterochromatin formation in the yeast Saccharomyces cerevisiae is characterized by the assembly of the Silent Information Regulator (SIR) complex, which consists of the histone deacetylase Sir2 and the structural components Sir3 and Sir4 and binds to unmodified nucleosomes to provide gene silencing. Sir3 contains an AAA(+) ATPase-like domain, and mutations in an exposed loop on the surface of this domain abrogate Sir3 silencing function in vivo as well in vitro binding to the Sir2/ Sir4 subcomplex. Here, we found that the removal of a single methyl group in the C-terminal coiled-coil domain (mutation T1314S) of Sir4 was sufficient to restore silencing at the silent mating-type loci HMR and HML to a Sir3 version with a mutation in this loop...
February 10, 2017: G3: Genes—Genomes—Genetics
https://www.readbyqxmd.com/read/28185826/chaetocin-a-histone-methyltransferase-inhibitor-impairs-proliferation-arrests-cell-cycle-and-induces-nucleolar-disassembly-in-trypanosoma-cruzi
#11
Aline Araujo Zuma, Jean de Oliveira Santos, Isabela Mendes, Wanderley de Souza, Carlos Renato Machado, E Maria Cristina M Motta
The Trypanosomatidae family includes pathogenic species of medical and veterinary interest. Chagas disease is endemic in Latin America, and about 8 million people are infected worldwide. There is a need for more effective drugs for the acute, undetermined and chronic phases of the disease that, in addition, do not cause side effects, stimulating the search for identification of new drug targets, as well as new chemotherapeutic targets. Trypanosomatids contain characteristic structures, such as the nucleus that undergoes a closed mitosis without chromosome formation and variations of chromatin packing in the different protozoa developmental stages...
February 6, 2017: Acta Tropica
https://www.readbyqxmd.com/read/28182012/loss-of-brg1-induces-crc-cell-senescence-by-regulating-p53-p21-pathway
#12
Guihua Wang, Yinjia Fu, Fuqing Hu, Jinqing Lan, Feng Xu, Xi Yang, Xuelai Luo, Jing Wang, Junbo Hu
Brahma-related gene-1 (BRG1) is the specific ATPase of switch/sucrose nonfermentable chromatin-remodeling complex that is aberrantly expressed or mutated in various cancers. However, the exact role of BRG1 in oncogenesis remains unknown. In this study, we demonstrate that the knockdown (KD) of BRG1 promotes cellular senescence by influencing the SIRT1/p53/p21 signal axis in colorectal cancer (CRC). In particular, we reveal that the expression level of BRG1 is inversely correlated with p21, one of the classic senescence regulators, and is decreased in senescent CRC cells...
February 9, 2017: Cell Death & Disease
https://www.readbyqxmd.com/read/28177615/an-unusual-topological-rna-architecture-with-an-eight-stranded-helical-fragment-containing-a-g-and-u-tetrads
#13
Chao-Da Xiao, Takumi Ishizuka, Xiao-Qing Zhu, Yue Li, Hiroshi Sugiyama, Yan Xu
Human telomeric RNA performs various cellular functions such as telomere length regulation, heterochromatin formation, and chromosome end protection. Using a combination of nuclear magnetic reso-nance (NMR), circular dichroism (CD), and gel electro-phoresis, we observed an unusual topological structure formed by human telomere RNA r(GUUAGGGU). Our results showed that every set of four strands formed a parallel G-quadruplex as symmetry-related units con-taining four G-tetrads, two U-tetrads, and one A-tetrad...
February 8, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28169523/the-suv39h1-protein-lysine-methyltransferase-methylates-chromatin-proteins-involved-in-heterochromatin-formation-and-vdj-recombination
#14
Srikanth Kudithipudi, Maren Kirstin Schuhmacher, Adam Fiseha Kebede, Albert Jeltsch
SUV39H1 is an H3K9 methyltransferase involved in the formation of heterochromatin. We investigated its substrate specificity profile and show recognition of H3 residues between K4 and G12 with highly specific readout of R8. The specificity profile of SUV39H1 is distinct from its paralog SUV39H2, indicating that they can have different additional substrates. Using the specificity profile, several novel SUV39H1 candidate substrates were identified. We observed methylation of 19 novel substrates at the peptide level and for 6 of them at the protein level...
February 7, 2017: ACS Chemical Biology
https://www.readbyqxmd.com/read/28169463/relationship-between-epigenetic-regulation-dietary-habits-and-the-developmental-origins-of-health-and-disease-theory
#15
REVIEW
Kazuki Mochizuki, Natsuyo Hariya, Kazue Honma, Toshinao Goda
Environmental stressors during developmental stages are hypothesized to increase the risk of developing metabolic diseases such as obesity, type 2 diabetes, hypertension, and psychiatric diseases during later life. This theory is known as the Developmental Origins of Health and Disease (DOHaD). Recent studies suggest that accumulation of environmental stress, including during developmental stages, is internalized as acquired information designated as "epigenetic memory." This epigenetic memory is generally indicated as DNA methylation and histone modifications in the chromatin...
February 7, 2017: Congenital Anomalies
https://www.readbyqxmd.com/read/28167679/independent-mechanisms-recruit-the-cohesin-loader-protein-nipbl-to-sites-of-dna-damage
#16
Christopher Bot, Annika Pfeiffer, Fosco Giordano, Dharani Manjeera Edara, Nico P Dantuma, Lena Ström
NIPBL is required to load the cohesin complex on to DNA. While the canonical role of cohesin is to couple replicated sister chromatids together until the onset of mitosis, it also promotes tolerance to DNA damage. Here we show that NIPBL is recruited to DNA damage throughout the cell cycle via independent mechanisms, influenced by type of damage. Firstly, the heterochromatin protein HP1γ recruits NIPBL to DSBs through the corresponding HP1-binding motif within the N-terminus. In contrast, the C-terminal HEAT repeat domain is unable to recruit NIPBL to DSBs but independently targets NIPBL to laser microirradiation induced DNA damage...
February 6, 2017: Journal of Cell Science
https://www.readbyqxmd.com/read/28167501/comprehensive-characterization-of-neutrophil-genome-topology
#17
Yina Zhu, Ke Gong, Matthew Denholtz, Vivek Chandra, Mark P Kamps, Frank Alber, Cornelis Murre
Neutrophils are responsible for the first line of defense against invading pathogens. Their nuclei are uniquely structured as multiple lobes that establish a highly constrained nuclear environment. Here we found that neutrophil differentiation was not associated with large-scale changes in the number and sizes of topologically associating domains (TADs). However, neutrophil genomes were enriched for long-range genomic interactions that spanned multiple TADs. Population-based simulation of spherical and toroid genomes revealed declining radii of gyration for neutrophil chromosomes...
February 6, 2017: Genes & Development
https://www.readbyqxmd.com/read/28160052/silencing-of-endogenous-retroviruses-by-heterochromatin
#18
REVIEW
Sophia Groh, Gunnar Schotta
Endogenous retroviruses (ERV) are an abundant class of repetitive elements in mammalian genomes. To ensure genomic stability, ERVs are largely transcriptionally silent. However, these elements also feature physiological roles in distinct developmental contexts, under which silencing needs to be partially relieved. ERV silencing is mediated through a heterochromatic structure, which is established by histone modification and DNA methylation machineries. This heterochromatic structure is largely refractory to transcriptional stimulation, however, challenges to the heterochromatic state, such as DNA replication, require re-establishment of the heterochromatic state in competition with transcriptional activators...
February 3, 2017: Cellular and Molecular Life Sciences: CMLS
https://www.readbyqxmd.com/read/28155885/regulation-of-pairing-between-broken-dna-containing-chromatin-regions-by-ku80-dna-pkcs-atm-and-53bp1
#19
Motohiro Yamauchi, Atsushi Shibata, Keiji Suzuki, Masatoshi Suzuki, Atsuko Niimi, Hisayoshi Kondo, Miwa Miura, Miyako Hirakawa, Keiko Tsujita, Shunichi Yamashita, Naoki Matsuda
Chromosome rearrangement is clinically and physiologically important because it can produce oncogenic fusion genes. Chromosome rearrangement requires DNA double-strand breaks (DSBs) at two genomic locations and misrejoining between the DSBs. Before DSB misrejoining, two DSB-containing chromatin regions move and pair with each other; however, the molecular mechanism underlying this process is largely unknown. We performed a spatiotemporal analysis of ionizing radiation-induced foci of p53-binding protein 1 (53BP1), a marker for DSB-containing chromatin...
February 3, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28154185/heterochromatin-protein-1%C3%AE-is-a-novel-epigenetic-repressor-of-human-embryonic-%C3%AF%C2%B5-globin-gene-expression
#20
Yadong Wang, Ying Wang, Lingling Ma, Min Nie, Junyi Ju, Ming Liu, Yexuan Deng, Bing Yao, Tao Gui, Xinyu Li, Chan Guo, Chi Ma, Renxiang Tan, Quan Zhao
Production of hemoglobin during development is tightly regulated. For example, expression from the human β-globin gene locus, comprising β-, δ-, ϵ-, and γ-globin genes, switches from ϵ-globin to γ-globin during embryonic development and then from γ-globin to β-globin after birth. Expression of human ϵ-globin in mice has been shown to ameliorate anemia caused by β-globin mutations, including those causing β-thalassemia and sickle cell disease (SCD), raising the prospect that reactivation of ϵ-globin expression could be used in managing these conditions in humans...
February 1, 2017: Journal of Biological Chemistry
keyword
keyword
20526
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"