scholarly journals The histone demethylase KDM5 is essential for larval growth in Drosophila

2018 ◽  
Author(s):  
Coralie Drelon ◽  
Helen M. Belalcazar ◽  
Julie Secombe
Keyword(s):  
Mammalian Cells ◽  
Cell Cycle Progression ◽  
Biological Activities ◽  
Larval Growth ◽  
Imaginal Discs ◽  
Complete Loss ◽  
Histone Demethylase ◽  
Ideal System ◽  
Demethylase Activity ◽  
Regulated Gene Expression

AbstractRegulated gene expression is necessary for developmental and homeostatic processes. The KDM5 family of proteins are histone H3 lysine 4 demethylases that can regulate transcription through both demethylase-dependent and independent mechanisms. While loss and overexpression of KDM5 proteins are linked to intellectual disability and cancer, respectively, their normal developmental functions remain less characterized. Drosophila melanogaster provides an ideal system to investigate KDM5 function, as it encodes a single ortholog in contrast to the four paralogs found in mammalian cells. To examine the consequences of complete loss of KDM5, we generated a null allele of Drosophila kdm5, also known as little imaginal discs (lid), and show that it is essential for development. Animals lacking KDM5 die during late pupal development but show a dramatically delayed larval development that coincides with decreased proliferation and increased cell death in imaginal discs. Interestingly, this developmental delay is independent of the well-characterized Jumonji C (JmjC) domain-encoded histone demethylase activity and plant homedomain (PHD) motif-mediated chromatin binding activities of KDM5, suggesting key functions for less characterized domains. Consistent with the phenotypes observed, transcriptome analyses of kdm5 null mutant wing imaginal discs revealed the dysregulation of genes involved in several cellular processes, including cell cycle progression and DNA repair. Together, our data provide the first description of complete loss of KDM5 function in a metazoan and offer an invaluable tool for defining the biological activities of KDM5 family proteins.

scholarly journals The UTX Tumor Suppressor Directly Senses Oxygen to Control Chromatin and Cell Fate

2019 ◽  
Author(s):  
Abhishek A. Chakraborty ◽  
Tuomas Laukka ◽  
Matti Myllykoski ◽  
Alison E. Ringel ◽  
Matthew A. Booker ◽  
...  
Keyword(s):  
Cell Fate ◽  
Indirect Effects ◽  
Mammalian Cells ◽  
Control Cell ◽  
Histone Demethylase ◽  
Hypoxic Induction ◽  
Hypoxic Conditions ◽  
Chromatin Regulators ◽  
Oxygen Sensitive ◽  
Demethylase Activity

AbstractMammalian cells express multiple 2-oxoglutarate (OG)-dependent dioxygenases, including many chromatin regulators. The oxygen affinities, and hence oxygen sensing capabilities, of the 2-oxoglutarate (OG)-dependent dioxygenases reported to date vary widely. Hypoxia can affect chromatin, but whether this reflects a direct effect on chromatin-modifying dioxygenases, or indirect effects caused by the hypoxic-induction of the HIF transcription factor or the endogenous 2-OG competitor 2-hydroxyglutarate (2-HG), is unclear. Here we report that hypoxia induces a HIF- and 2-HG-independent histone modification signature consistent with KDM inactivation. We also show that the H3K27 histone demethylase KDM6A (also called UTX), but not its paralog KDM6B, is oxygen-sensitive. KDM6A loss, like hypoxia, prevented H3K27me3 erasure and blocked differentiation. Conversely, restoring H3K27me3 homeostasis in hypoxic cells reversed these effects. Therefore, oxygen directly affects chromatin regulators to control cell fate.One Sentence SummaryKDM6A demethylase activity is diminished under hypoxic conditions and causes changes in gene expression programs that govern cell fate.

Structure of the JmjC-domain-containing protein JMJD5

2013 ◽  
Vol 69 (10) ◽  
pp. 1911-1920 ◽  
Author(s):  
Haipeng Wang ◽  
Xing Zhou ◽  
Minhao Wu ◽  
Chengliang Wang ◽  
Xiaoqin Zhang ◽  
...  
Keyword(s):  
Cell Cycle Progression ◽  
Embryonic Cell ◽  
Histone Demethylase ◽  
Amino Acid Residues ◽  
Lysine Methylation ◽  
Post Translational Modification ◽  
Active Centre ◽  
Histone Tails ◽  
Demethylase Activity ◽  
Jmjc Domain

The post-translational modification of histone tails is the principal process controlling epigenetic regulation in eukaryotes. The lysine methylation of histones is dynamically regulated by two distinct classes of enzymes: methyltransferases and demethylases. JMJD5, which plays an important role in cell-cycle progression, circadian rhythms and embryonic cell proliferation, has been shown to be a JmjC-domain-containing histone demethylase with enzymatic activity towards H3K36me2. Here, the crystal structure of human JMJD5 lacking the N-terminal 175 amino-acid residues is reported. The structure showed that the Gln275, Trp310 and Trp414 side chains might block the insertion of methylated lysine into the active centre of JMJD5, suppressing the histone demethylase activity of the truncated JMJD5 construct. A comparison of the structure of JMJD5 with that of FIH, a well characterized protein hydroxylase, revealed that human JMJD5 might function as a protein hydroxylase. The interaction between JMJD5 and the core histone octamer proteins indicated that the histone proteins could be potential substrates for JMJD5.

scholarly journals Primase p49 mRNA expression is serum stimulated but does not vary with the cell cycle.

1989 ◽  
Vol 9 (5) ◽  
pp. 1940-1945 ◽  
Author(s):  
B Y Tseng ◽  
C E Prussak ◽  
M T Almazan
Keyword(s):  
Cell Cycle ◽  
Dna Synthesis ◽  
Mammalian Cells ◽  
Cell Cycle Progression ◽  
Small Subunit ◽  
Mrna Levels ◽  
Proliferating Cells ◽  
Restriction Point ◽  
Serum Stimulation ◽  
G1 Cells

Expression of the small-subunit p49 mRNA of primase, the enzyme that synthesizes oligoribonucleotides for initiation of DNA replication, was examined in mouse cells stimulated to proliferate by serum and in growing cells. The level of p49 mRNA increased approximately 10-fold after serum stimulation and preceded synthesis of DNA and histone H3 mRNA by several hours. Expression of p49 mRNA was not sensitive to inhibition by low concentrations of cycloheximide, which suggested that the increase in mRNA occurred before the restriction point control for cell cycle progression described for mammalian cells and was not under its control. p49 mRNA levels were not coupled to DNA synthesis, as observed for the replication-dependent histone genes, since hydroxyurea or aphidicolin had no effect on p49 mRNA levels when added before or during S phase. These inhibitors did have an effect, however, on the stability of p49 mRNA and increased the half-life from 3.5 h to about 20 h, which suggested an interdependence of p49 mRNA degradation and DNA synthesis. When growing cells were examined after separation by centrifugal elutriation, little difference was detected for p49 mRNA levels in different phases of the cell cycle. This was also observed when elutriated G1 cells were allowed to continue growth and then were blocked in M phase with colcemid. Only a small decrease in p49 mRNA occurred, whereas H3 mRNA rapidly decreased, when cells entered G2/M. These results indicate that the level of primase p49 mRNA is not cell cycle regulated but is present constitutively in proliferating cells.

Overexpression of kin17 protein disrupts nuclear morphology and inhibits the growth of mammalian cells

1999 ◽  
Vol 112 (19) ◽  
pp. 3215-3224 ◽  
Author(s):  
P. Kannouche ◽  
J.F. Angulo
Keyword(s):  
Dna Replication ◽  
Mammalian Cells ◽  
Cell Cycle Progression ◽  
Reca Protein ◽  
S Phase ◽  
Expression Vectors ◽  
Nuclear Morphology ◽  
Functional Domain ◽  
Genetic Response ◽  
Cycle Progression

UVC or ionizing radiation of mammalian cells elicits a complex genetic response that allows recovery and cell survival. Kin17 gene, which is highly conserved among mammals, is upregulated during this response. Kin17 gene encodes a 45 kDa protein which binds to DNA and presents a limited similarity with a functional domain of the bacterial RecA protein. Kin17 protein is accumulated in the nucleus of proliferating fibroblasts and forms intranuclear foci. Using expression vectors, we show that overexpression of kin17 protein inhibits cell-cycle progression into S phase. Our results indicate that growth inhibition correlates with disruption of the nuclear morphology which seems to modify the intranuclear network required during the early steps of DNA replication. We report that a mutant encoding a protein deleted from the central domain of kin17 protein enhanced these effects whereas the deletion of the C-terminal domain considerably reduced them. These mutants will be used to elucidate the molecular mechanism by which kin17 protein alters cell growth and DNA replication.

scholarly journals Overall Cdk activity modulates the DNA damage response in mammalian cells

2009 ◽  
Vol 187 (6) ◽  
pp. 773-780 ◽  
Author(s):  
Antonio Cerqueira ◽  
David Santamaría ◽  
Bárbara Martínez-Pastor ◽  
Miriam Cuadrado ◽  
Oscar Fernández-Capetillo ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Damage Response ◽  
Mammalian Cells ◽  
Cell Cycle Progression ◽  
Cyclin Dependent Kinase ◽  
Genome Maintenance ◽  
Cycle Progression ◽  
Damage Response ◽  
Dna Break ◽  
Specific Contribution

In response to DNA damage, cells activate a phosphorylation-based signaling cascade known as the DNA damage response (DDR). One of the main outcomes of DDR activation is inhibition of cyclin-dependent kinase (Cdk) activity to restrain cell cycle progression until lesions are healed. Recent studies have revealed a reverse connection by which Cdk activity modulates processing of DNA break ends and DDR activation. However, the specific contribution of individual Cdks to this process remains poorly understood. To address this issue, we have examined the DDR in murine cells carrying a defined set of Cdks. Our results reveal that genome maintenance programs of postreplicative cells, including DDR, are regulated by the overall level of Cdk activity and not by specific Cdks.

scholarly journals Diversity Focused Semisyntheses of Tetronate Polyether Ionophores

2019 ◽  
Author(s):  
Shaoquan Lin ◽  
Han Liu ◽  
Esben B. Svenningsen ◽  
Christine Pedersen ◽  
Peter Nørby ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Cancer Cells ◽  
Mammalian Cells ◽  
Biological Activities ◽  
Structural Diversity ◽  
Bacterial Activity ◽  
Cation Binding ◽  
Detailed Understanding ◽  
Structure Activity ◽  
Aggressive Cancer

The polyether ionophores are complex natural products capable of transporting cations across biological membranes. Many family members possess highly potent antimicrobial activity and a few selected compounds have ability to target particularly aggressive cancer cells. Despite these interesting perspectives, a detailed understanding of the cellular mode-of-action of polyether ionophores is generally lacking. In principle, broad mapping of structure-activity relationships across several biological activities could provide mechanistic insights as well as identification of lead structures but access to structural diversity within the overall class is synthetically very challenging. In this manuscript, we demonstrate that novel polyether ionophores can be constructed by recycling components of highly abundant polyethers. We provide the first examples of synthetically incorporating halogen-functionalized tetronic acids as cation-binding groups into polyether ionophores and we identify analogs with strong anti-bacterial activity and minimal effects on mammalian cells.

scholarly journals Characterization and Identification of Cryptic Biopeptides inCarya illinoinensis(Wangenh K. Koch) Storage Proteins

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Everardo Mares-Mares ◽  
Santiago Gutiérrez-Vargas ◽  
Luis Pérez-Moreno ◽  
Leandro G. Ordoñez-Acevedo ◽  
José E. Barboza-Corona ◽  
...  
Keyword(s):  
Cancer Cells ◽  
Cell Cycle Progression ◽  
Bioactive Peptides ◽  
Storage Proteins ◽  
Biological Activities ◽  
Cancer Therapies ◽  
In Silico Prediction ◽  
Major Fraction ◽  
Cycle Progression ◽  
Cervical Cancer Cells

The objective of this research was to identify and characterize the encoded peptides present in nut storage proteins ofCarya illinoinensis. It was found, through in silico prediction, proteomic analysis, and MS spectrometry, that bioactive peptides were mainly found in albumin and glutelin fractions. Glutelin was the major fraction with ~53% of the nut storage proteins containing at least 21 peptides with different putative biological activities, including antihypertensives, antioxidants, immunomodulators, protease inhibitors, and inhibitors of cell cycle progression in cancer cells. Data showed that using 50 μg/mL tryptic digests of enriched peptides obtained from nut glutelins is able to induce up to 19% of apoptosis in both HeLa and CasKi cervical cancer cells. To our knowledge, this is the first report that shows the potential value of the nut-encoded peptides to be considered as adjuvants in cancer therapies.

scholarly journals Functional Studies of MLL-AF4 and a Murinized pSer-variant thereof: MLL-AF4 Impairs the Ribosome Biosynthesis Pathway

2021 ◽  
Author(s):  
Anna Lena Siemund ◽  
Eric Kowarz ◽  
Rolf Marschalek
Keyword(s):  
Transcription Factor ◽  
Fusion Protein ◽  
Mammalian Cells ◽  
Biological Activities ◽  
Intracellular Localization ◽  
Biological Behavior ◽  
Hematopoietic Stem ◽  
Functional Studies ◽  
Pol I ◽  
Transcription Factor Complex

Abstract Background: Recent pathomolecular studies on the MLL-AF4 fusion protein revealed that the murinized version of MLL-AF4, the MLL-Af4 fusion protein, was able to induce leukemia when expressed in murine or human hematopoietic stem/progenitor cells (1). In parallel, a group from Japan demonstrated that the pSer domain of the AF4 protein, as well as the pSer domain of the MLL-AF4 fusion is able to bind the Pol I transcription factor complex SL1 (2).Here, we investigated the human MLL-AF4 and a pSer-murinized version thereof for their functional properties in mammalian cells. Gene expression profiling studies were complemented by intracellular localization studies and functional experiments concerning the biological activities in the nuecleolus.Results: Based on our results, we have to conclude that MLL-AF4 is predominantly localizing in the nucleolus, thereby interfering withPol I transcription, and subsequently,also ribosomebiogenesis. The murinized pSer-variant is more localizing in the nucleus, which may explain their different biological behavior. Of note, AF4-MLL is cooperating at the molecular level with MLL-AF4, but not with the pSer-murinized version of it.Conclusion: This study provides new insights and a molecular explanation for the known differences between hMLL-hAF4 (not leukemogenic) and hMLL-mAf4 (leukemogenic). While the human pSer domain is able to efficiently recruit the SL1 transcription factor complex, the murine counterpart is not. This has several consequences for our understanding of t(4;11) leukemia which is by far the most frequent leukemia in infants, childhood and adults suffering from MLL-r acute leukemia.

Cell cycle progression, growth and patterning in imaginal discs despite inhibition of cell division after inactivation of Drosophila Cdc2 kinase

Development ◽  
1997 ◽  
Vol 124 (18) ◽  
pp. 3555-3563 ◽  
Author(s):  
K. Weigmann ◽  
S.M. Cohen ◽  
C.F. Lehner
Keyword(s):  
Cell Division ◽  
Cell Cycle Progression ◽  
Positional Information ◽  
Imaginal Discs ◽  
Physical Distance ◽  
Cdc2 Kinase ◽  
Cycle Progression ◽  
Mitotic Kinase ◽  
Control Growth ◽  
Local Cell

During larval development, Drosophila imaginal discs increase in size about 1000-fold and cells are instructed to acquire distinct fates as a function of their position. The secreted signaling molecules Wingless and Decapentaplegic have been implicated as sources of positional information that globally control growth and patterning. Evidence has also been presented that local cell interactions play an important role in controlling cell proliferation in imaginal discs. As a first step to understanding how patterning cues influence growth we investigated the effects of blocking cell division at different times and in spatially controlled manner by inactivation of the mitotic kinase Cdc2 in developing imaginal discs. We find that cell growth continues after inactivation of Cdc2, with little effect on overall patterning. The mechanisms that regulate size of the disc therefore do not function by regulating cell division, but appear to act primarily by regulating size in terms of physical distance or tissue volume.

scholarly journals Computationally enhanced quantitative phase microscopy reveals autonomous oscillations in mammalian cell growth

2020 ◽  
Vol 117 (44) ◽  
pp. 27388-27399
Author(s):  
Xili Liu ◽  
Seungeun Oh ◽  
Leonid Peshkin ◽  
Marc W. Kirschner
Keyword(s):  
Cell Cycle ◽  
Growth Rate ◽  
Cell Growth ◽  
Mammalian Cells ◽  
Cell Cycle Progression ◽  
Cell Tracking ◽  
Fundamental Property ◽  
Quantitative Phase ◽  
Phase Microscopy ◽  
Quantitative Phase Microscopy

The fine balance of growth and division is a fundamental property of the physiology of cells, and one of the least understood. Its study has been thwarted by difficulties in the accurate measurement of cell size and the even greater challenges of measuring growth of a single cell over time. We address these limitations by demonstrating a computationally enhanced methodology for quantitative phase microscopy for adherent cells, using improved image processing algorithms and automated cell-tracking software. Accuracy has been improved more than twofold and this improvement is sufficient to establish the dynamics of cell growth and adherence to simple growth laws. It is also sufficient to reveal unknown features of cell growth, previously unmeasurable. With these methodological and analytical improvements, in several cell lines we document a remarkable oscillation in growth rate, occurring throughout the cell cycle, coupled to cell division or birth yet independent of cell cycle progression. We expect that further exploration with this advanced tool will provide a better understanding of growth rate regulation in mammalian cells.

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