The P-element-induced silencing effect of KP transposons is dose dependent in Drosophila melanogaster

Genome ◽  
2011 ◽  
Vol 54 (9) ◽  
pp. 752-762 ◽  
Author(s):  
Alireza Sameny ◽  
John Locke
Keyword(s):  
Drosophila Melanogaster ◽  
Critical Role ◽  
Mutagenic Effect ◽  
P Element ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
P Elements ◽  
Single Well ◽  
Dose Dependent

Transposable elements are found in the genomes of all eukaryotes and play a critical role in altering gene expression and genome organization. In Drosophila melanogaster, transposable P elements are responsible for the phenomenon of hybrid dysgenesis. KP elements, a deletion-derivative of the complete P element, can suppress this mutagenic effect. KP elements can also silence the expression of certain other P-element-mediated transgenes in a process called P-element-dependent silencing (PDS), which is thought to involve the recruitment of heterochromatin proteins. To explore the mechanism of this silencing, we have mobilized KP elements to create a series of strains that contain single, well-defined KP insertions that show PDS. To understand the quantitative role of KP elements in PDS, these single inserts were combined in a series of crosses to obtain genotypes with zero, one, or two KP elements, from which we could examine the effect of KP gene dose. The extent of PDS in these genotypes was shown to be dose dependent in a logarithmic rather than linear fashion. A logarithmic dose dependency is consistent with the KP products interacting with heterochromatic proteins in a concentration-dependent manner such that two molecules are needed to induce gene silencing.

Mutations in ash1 and trx enhance P-element-dependent silencing in Drosophila melanogaster

Genome ◽  
2016 ◽  
Vol 59 (8) ◽  
pp. 527-540
Author(s):  
Allen McCracken ◽  
John Locke
Keyword(s):  
Drosophila Melanogaster ◽  
Spontaneous Mutation ◽  
Position Effect ◽  
P Element ◽  
Position Effect Variegation ◽  
Genetic Modifiers ◽  
Gypsy Element ◽  
P Elements ◽  
Opposite Action ◽  
Dose Dependent

In Drosophila melanogaster, the mini-w+ transgene in Pci is normally expressed throughout the adult eye; however, when other P or KP elements are present, a variegated-eye phenotype results, indicating random w+ silencing during development called P-element-dependent silencing (PDS). Mutant Su(var)205 and Su(var)3-7 alleles act as haplo-suppressors/triplo-enhancers of this variegated phenotype, indicating that these heterochromatic modifiers act dose dependently in PDS. Previously, we recovered a spontaneous mutation of P{lacW}ciDplac called P{lacW}ciDplacE1 (E1) that variegated in the absence of P elements, presumably due to the insertion of an adjacent gypsy element. From a screen for genetic modifiers of E1 variegation, we describe here the isolation of five mutations in ash1 and three in trx that enhance the E1 variegated phenotype in a dose-dependent and cumulative manner. These mutant alleles enhance PDS at E1, and in E1/P{lacW}ciDplac, but suppress position effect variegation (PEV) at In(1)wm4. This opposite action is consistent with a model where ASH1 and TRX mark transcriptionally active chromatin domains. If ASH1 or TRX function is lost or reduced, heterochromatin can spread into these domains creating a sink that diverts heterochromatic proteins from other variegating locations, which then may express a suppressed phenotype.

scholarly journals Genetic Transformation of Drosophila melanogaster with an Autonomous P Element: Phenotypic and Molecular Analyses of Long-Established Transformed Lines

Genetics ◽  
1987 ◽  
Vol 115 (4) ◽  
pp. 711-723
Author(s):  
Stephen B Daniels ◽  
Stephen H Clark ◽  
Margaret G Kidwell ◽  
Arthur Chovnick
Keyword(s):  
Drosophila Melanogaster ◽  
The Other ◽  
P Element ◽  
Stable Configuration ◽  
Phenotypic Properties ◽  
Molecular Analyses ◽  
P Elements ◽  
Regulatory Ability ◽  
Rate Of Increase

ABSTRACT Following transformation of a Drosophila melanogaster true M strain with an autonomous P element, six lines were established and monitored for their molecular and phenotypic properties during a 4-yr period. The number of P elements increased with time in all the lines but the rate of increase differed among lines. Furthermore, degenerate elements arose in each of the lines during propagation. By the end of the 4th yr, the total number of elements in every line was similar to that of a very strong P strain.—At the phenotypic level, all of the transformed lines evolved high P activity, but only three developed complete or nearly complete regulatory ability. The other three lines attained only intermediate levels of regulation over the 4-yr period. One of these lines was particularly noteworthy. Although it contained as many as 55 P elements per genome (20 of which were potentially complete) and had extremely high P activity potential, it continued to exhibit limited regulatory ability. In addition, when females of this line were maintained at high temperatures, the ability to suppress P activity was even further diminished. A strain with this combination of molecular and phenotypic properties, in an apparently stable configuration, has not been previously described.—The results are discussed in the context of the possible role of degenerate elements in regulating P element expression.

scholarly journals MicroRNA-19b-3p promotes cell proliferation and osteogenic differentiation of BMSCs by interacting with lncRNA H19

2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Gan Xiaoling ◽  
Liu Shuaibin ◽  
Liang Kailu
Keyword(s):  
Cell Proliferation ◽  
Protein Expression ◽  
Postmenopausal Osteoporosis ◽  
Critical Role ◽  
Dependent Manner ◽  
Cell Proliferation And Differentiation ◽  
Proliferation And Differentiation ◽  
17Β Estradiol ◽  
Dose Dependent

Abstract Background To investigated the role of miR-19b-3p in regulating bone marrow mesenchymal stem cell (BMSC) proliferation and osteoblast differentiation. Methods The expression of miR-19b-3p and lncRNA H19 were measured in postmenopausal osteoporosis patients and BMP-22 induced BMSCs using qRT-PCR. MiR-19b-3p mimic or inhibitor was transfected into BMP-2 induced BMSCs. Cell proliferation was measured by BrdU method. Protein expression of RUNX2 and COL1A1 were measured by western blot. PcDNA3.1-lncRNA H19 with or without miR-19b-3p mimic was transfected into BMP-2 induced BMSCs. Results The expression of miR-19b-3p was significantly up-regulated in postmenopausal osteoporosis patients and BMP-2 induced BMSCs. MiR-19b-3p overexpression dramatically elevated, while miR-19b-3p inhibition decreased cell proliferation of BMSCs. Additionally, protein expression levels of RUNX2 and COL1A1, as well as ALP activity were significantly promoted by miR-19b-3p mimic transfection and inhibited by miR-19b-3p inhibitor transfection. LncRNA H19 was obviously down-regulated in postmenopausal osteoporosis patients. H19 overexpression significantly decreased cell proliferation and differentiation by down-regulating miR-19b-3p. Moreover, the expression of miR-19b-3p was inhibited, while H19 elvated in 17β-estradiol (E2) treated BMSCs in a dose-dependent manner. Conclusion These data were the first to reveal the critical role of H19/miR-19b-3p in postmenopausal osteoporosis, and provided a new therapeutic target for OP.

Histamine inhibits atrial myocytic ANP release via H2 receptor-cAMP-protein kinase signaling

2003 ◽  
Vol 285 (2) ◽  
pp. R380-R393 ◽  
Author(s):  
Dan Li ◽  
Jin Fu Wen ◽  
Jing Yu Jin ◽  
Hua Jin ◽  
Hai Sun Ann ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Selective Inhibitor ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Camp Analog ◽  
Induced Changes ◽  
Protein Kinase Signaling ◽  
Dose Dependent ◽  
Rabbit Atria

Changes in cyclic nucleotide production and atrial dynamics have been known to modulate atrial natriuretic peptide (ANP) release. Although cardiac atrium expresses histamine receptors and contains histamine, the role of histamine in the regulation of ANP release has to be defined. The purpose of the present study was to define the effect of histamine on the regulation of ANP release in perfused beating rabbit atria. Histamine decreased ANP release concomitantly with increases in cAMP efflux and atrial dynamics in a concentration-dependent manner. Histamine-induced decrease in ANP release was a function of an increase in cAMP production. Blockade of histamine H2 receptor with cimetidine but not of H1 receptor with triprolidine abolished the responses of histamine. Cell-permeable cAMP analog, 8-Br-cAMP, mimicked the effects of histamine, and the responses were dose-dependent and blocked by a protein kinase A (PKA)-selective inhibitor, KT5720. Nifedipine failed to modulate histamine-induced decrease in ANP release. Protein kinase nonselective inhibitor staurosporine blocked histamine-induced changes in a concentration-dependent manner. KT5720 and RP-adenosine 3′,5′-cyclic monophosphorothioate, another PKA-selective inhibitor, attenuated histamine-induced changes. These results suggest that histamine decreases atrial ANP release by H2 receptor-cAMP signaling via PKA-dependent and -independent pathways.

scholarly journals Induction of PGF2α Synthesis by Cortisol Through GR Dependent Induction of CBR1 in Human Amnion Fibroblasts

Endocrinology ◽  
2014 ◽  
Vol 155 (8) ◽  
pp. 3017-3024 ◽  
Author(s):  
Chunming Guo ◽  
Wangsheng Wang ◽  
Chao Liu ◽  
Leslie Myatt ◽  
Kang Sun
Keyword(s):  
Rna Polymerase Ii ◽  
Critical Role ◽  
Prostaglandin F2α ◽  
Fetal Membranes ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Human Amnion ◽  
Antagonist Ru486 ◽  
Human Parturition

Abundant evidence indicates a pivotal role of prostaglandin F2α (PGF2α) in human parturition. Both the fetal and maternal sides of the fetal membranes synthesize PGF2α. In addition to the synthesis of PGF2α from PGH2 by PGF synthase (PGFS), PGF2α can also be converted from PGE2 by carbonyl reductase 1 (CBR1). Here, we showed that there was concurrent increased production of cortisol and PGF2α in association with the elevation of CBR1 in human amnion obtained at term with labor versus term without labor. In cultured primary human amnion fibroblasts, cortisol (0.01–1μM) increased PGF2α production in a concentration-dependent manner, in parallel with elevation of CBR1 levels. Either siRNA-mediated knockdown of glucocorticoid receptor (GR) expression or GR antagonist RU486 attenuated the induction of CBR1 by cortisol. Chromatin immunoprecipitation (ChIP) showed an increased enrichment of both GR and RNA polymerase II to CBR1 promoter. Knockdown of CBR1 expression with siRNA or inhibition of CBR1 activity with rutin decreased both basal and cortisol-stimulated PGF2α production in human amnion fibroblasts. In conclusion, CBR1 may play a critical role in PGF2α synthesis in human amnion fibroblasts, and cortisol promotes the conversion of PGE2 into PGF2α via GR-mediated induction of CBR1 in human amnion fibroblasts. This stimulatory effect of cortisol on CBR1 expression may partly explain the concurrent increases of cortisol and PGF2α in human amnion tissue with labor, and these findings may account for the increased production of PGF2α in the fetal membranes prior to the onset of labor.

scholarly journals High Glucose Induces Sumoylation of Smad4 via SUMO2/3 in Mesangial Cells

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Xueqin Zhou ◽  
Chenlin Gao ◽  
Wei Huang ◽  
Maojun Yang ◽  
Guo Chen ◽  
...  
Keyword(s):  
High Glucose ◽  
Laser Scanning ◽  
Transforming Growth Factor ◽  
Mesangial Cells ◽  
Critical Role ◽  
Confocal Laser ◽  
Dependent Manner ◽  
High Glucose Condition ◽  
Dose Dependent

Recent studies have shown that sumoylation is a posttranslational modification involved in regulation of the transforming growth factor-β(TGF-β) signaling pathway, which plays a critical role in renal fibrosis in diabetic nephropathy (DN). However, the role of sumoylation in the regulation of TGF-βsignaling in DN is still unclear. In the present study, we investigated the expression of SUMO (SUMO1 and SUMO2/3) and Smad4 and the interaction between SUMO and Smad4 in cultured rat mesangial cells induced by high glucose. We found that SUMO1 and SUMO2/3 expression was significantly increased in the high glucose groups compared to the normal groupP<0.05. Smad4 and fibronectin (FN) levels were also increased in the high glucose groups in a dose-dependent manner. Coimmunoprecipitation and confocal laser scanning revealed that Smad4 interacted and colocalized with SUMO2/3, but not with SUMO1 in mesangial cells. Sumoylation (SUMO2/3) of Smad4 under high glucose condition was strongly enhanced compared to normal controlP<0.05. These results suggest that high glucose may activate TGF-β/Smad signaling through sumoylation of Samd4 by SUMO2/3 in mesangial cells.

Role of paraventricular nucleus in control of blood pressure and drinking in rats

1992 ◽  
Vol 262 (6) ◽  
pp. F1068-F1075 ◽  
Author(s):  
L. L. Jensen ◽  
J. W. Harding ◽  
J. W. Wright
Keyword(s):  
Blood Pressure ◽  
Paraventricular Nucleus ◽  
Critical Role ◽  
Systemic Blood Pressure ◽  
Dependent Manner ◽  
Ang Ii ◽  
Sprague Dawley ◽  
Systemic Blood ◽  
Dose Dependent

The present investigation examined the abilities of angiotensin (ANG) II and III to produce increases in blood pressure and drinking when microinfused into the paraventricular nucleus (PVN) of the hypothalamus of the Sprague-Dawley rat. Dose-dependent elevations in systemic blood pressure and heart rate were measured to both ANG II and III in the anesthetized rat, with ANG II more potent than ANG III at the two highest doses examined. Pretreatment with the specific ANG receptor antagonist [Sar1,Thr8]ANG II (sarthran), blocked subsequent ANG II- and III-induced elevations in blood pressure, suggesting that these responses were dependent on the activation of ANG receptors. A similar analysis in awake rats yielded nearly equivalent results. A final experiment demonstrated that microinfusions of ANG II and III into the PVN produced drinking in a dose-dependent manner, with greater consumption to ANG II than ANG III. Again, sarthran was found to block the dipsogenic response. Histological examination revealed that the location of the injection site was linked to the character of the ANG-dependent response. These data suggest that the PVN may play a critical role in mediating central ANG effects on body water homeostasis and blood pressure regulation. Furthermore, it appears that subnuclei of the PVN may participate differentially in ANG-mediated actions.

Myeloperoxidase Is a Negative Regulator of Phospholipid-Dependent Coagulation

2017 ◽  
Vol 117 (12) ◽  
pp. 2300-2311 ◽  
Author(s):  
Lennart Beckmann ◽  
Christina Dicke ◽  
Brigitte Spath ◽  
Carina Lehr ◽  
Bianca Sievers ◽  
...  
Keyword(s):  
Whole Blood ◽  
Critical Role ◽  
Negative Regulator ◽  
Dependent Manner ◽  
Antibody Treatment ◽  
Concentration Dependent Manner ◽  
Activated Platelets ◽  
Heme Enzyme ◽  
Neutrophilic Polymorphonuclear Leukocytes

AbstractMyeloperoxidase (MPO) is a cationic heme enzyme stored in neutrophilic polymorphonuclear leukocytes (PMNs) that has recently been implicated in inflammatory cell signaling and tissue damage. Although PMNs play a critical role in both innate immunity and vascular thrombosis, no previous study has systematically investigated the effect of MPO on blood coagulation. Here, we show that PMN-derived MPO inhibits the procoagulant activity (PCA) of lipidated recombinant human tissue factor (rhTF) in a time- and concentration-dependent manner that involves, but is not entirely dependent on the enzyme's catalytic activity. Similarly, MPO together with its substrate, H2O2, inhibited the PCA of plasma microvesicles isolated from lipopolysaccharide (LPS)-stimulated whole blood, an effect additive to that of a function blocking TF antibody. Treatment of whole blood with LPS or phorbol-myristate-acetate dramatically increased MPO plasma levels, and co-incubation with 4-ABAH, a specific MPO inhibitor, significantly enhanced the PCA in plasma supernatants. MPO and MPO/H2O2 also inhibited the PCA of activated platelets and purified phospholipids (PLs), suggesting that modulation of negatively charged PLs, i.e., phosphatidylserine, rather than direct interference with the TF/FVIIa initiation complex was involved. Consistently, pretreatment of activated platelets with MPO or MPO/H2O2 attenuated the subsequent binding of lactadherin, which specifically recognizes procoagulant PS on cell membranes. Finally, endogenously released MPO regulated the PCA of THP1 cells in an autocrine manner dependent on the binding to CD11b/CD18 integrins. Collectively, these findings indicate that MPO is a negative regulator of PL-dependent coagulation and suggest a more complex role of activated PMNs in haemostasis and thrombosis.

scholarly journals N-hydroxylamine is not an intermediate in the conversion of l-arginine to an activator of soluble guanylate cyclase in neuroblastoma N1E-115 cells

1991 ◽  
Vol 273 (3) ◽  
pp. 547-552 ◽  
Author(s):  
S Pou ◽  
W S Pou ◽  
G M Rosen ◽  
E E el-Fakahany
Keyword(s):  
Guanylate Cyclase ◽  
Cyclic Gmp ◽  
Soluble Guanylate Cyclase ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Intact Cells ◽  
Relaxing Factor ◽  
Endothelium Derived Relaxing Factor ◽  
Dose Dependent

This study evaluates the role of N-hydroxylamine (NH2OH) in activating soluble guanylate cyclase in the mouse neuroblastoma clone N1E-115. It has been proposed that NH2OH is a putative intermediate in the biochemical pathway for the generation of nitric oxide (NO)/endothelium-derived relaxing factor (EDRF) from L-arginine. NH2OH caused a time- and concentration-dependent increase in cyclic GMP formation in intact cells. This response was not dependent on Ca2+. In cytosol preparations the activation of guanylate cyclase by L-arginine was dose-dependent and required Ca2+ and NADPH. In contrast, NH2OH itself did not activate cytosolic guanylate cyclase but it inhibited the basal activity of this enzyme in a concentration-dependent manner. The formation of cyclic GMP in the cytosolic fractions in response to NH2OH required the addition of catalase and H2O2. On the other hand, catalase and/or H2O2 lead to a decrease in L-arginine-induced cyclic GMP formation. Furthermore, NH2OH inhibited L-arginine- and sodium nitroprusside-induced cyclic GMP formation in the cytosol. The inhibition of L-arginine-induced cyclic GMP formation in the cytosol by NH2OH was not reversed by the addition of superoxide dismutase. These data strongly suggest that NH2OH is not a putative intermediate in the metabolism of L-arginine to an activator of guanylate cyclase.

Reversibility of increased microvessel permeability in response to VE-cadherin disassembly

2000 ◽  
Vol 279 (6) ◽  
pp. L1218-L1225 ◽  
Author(s):  
Xiaopei Gao ◽  
Panos Kouklis ◽  
Ning Xu ◽  
Richard D. Minshall ◽  
Raudel Sandoval ◽  
...  
Keyword(s):  
Surface Area ◽  
Adhesive Contact ◽  
Dependent Manner ◽  
Vascular Endothelial ◽  
Concentration Dependent Manner ◽  
Permeability Surface ◽  
Microvessel Permeability ◽  
Area Product ◽  
Dose Dependent

We determined the role of vascular endothelial (VE)-cadherin complex in regulating the permeability of pulmonary microvessels. Studies were made in mouse lungs perfused with albumin-Krebs containing EDTA, a Ca2+ chelator, added to study the VE-cadherin junctional disassembly. We then repleted the perfusate with Ca2+ to restore VE-cadherin integrity. Confocal microscopy showed a disappearance of VE-cadherin immunostaining in a time- and dose-dependent manner after Ca2+ chelation and reassembly of the VE-cadherin complex within 5 min after Ca2+ repletion. We determined the125I-labeled albumin permeability-surface area product and capillary filtration coefficient ( K fc) to quantify alterations in the pulmonary microvessel barrier. The addition of EDTA increased 125I-albumin permeability-surface area product and K fc in a concentration-dependent manner within 5 min. The permeability response was reversed within 5 min after repletion of Ca2+. An anti-VE-cadherin monoclonal antibody against epitopes responsible for homotypic adhesion augmented the increase in K fc induced by Ca2+chelation and prevented reversal of the response. We conclude that the disassembled VE-cadherins in endothelial cells are mobilized at the junctional plasmalemmal membrane such that VE-cadherins can rapidly form adhesive contact and restore microvessel permeability by reannealing the adherens junctions.

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