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Responsive Genes (responsive + gene)
Selected AbstractsPeriostin promotes a fibroblastic lineage pathway in atrioventricular valve progenitor cellsDEVELOPMENTAL DYNAMICS, Issue 5 2009Russell A. Norris Abstract Differentiation of prevalvular mesenchyme into valve fibroblasts is an integral step towards the development of functionally mature cardiac valves. Although clinically relevant, little is known regarding the molecular and cellular mechanisms by which this process proceeds. Genes that are regulated in a spatio-temporal pattern during valve remodeling are candidates for affecting this differentiation process. Based on its expression pattern, we have focused our studies on the role of the matricellular gene, periostin, in regulating the differentiation of cushion mesenchymal cells into valve fibroblasts. Herein, we demonstrate that periostin expression is coincident with and regulates type I collagen protein production, a major component of mature valve tissue. Adenoviral-mediated knock-down of periostin in atrioventricular mesenchyme resulted in a decrease in collagen I protein expression and aberrant induction of myocyte markers indicating an alteration in AV mesenchyme differentiation. In vitro analyses using a novel "cardiotube" assay further demonstrated that expression of periostin regulates lineage commitment of valve precursor cells. In these cells, expression of periostin and collagen I are regulated, in part, by TGF,-3. We further demonstrate that TGF,-3, through a periostin/collagen pathway, enhances the viscoelastic properties of AV cushion tissue surface tension and plays a crucial role in regulating valve remodeling. Thus, data presented here demonstrate that periostin, a TGF,-3 responsive gene, functions as a crucial mediator of chick AV valve maturation via promoting mesenchymal-to-fibroblast differentiation while blocking differentiation of alternative cell types (myocytes). Developmental Dynamics 238:1052,1063, 2009. © 2009 Wiley-Liss, Inc. [source] Conserved cellular function and stress-mediated regulation among members of the proteolipid protein familyJOURNAL OF NEUROSCIENCE RESEARCH, Issue 6 2010María E. Fernández Abstract Chronic stress causes morphological alterations in the hippocampus of rodents and tree shrews, including atrophy of CA3 dendrites and loss of synapses. The molecular mechanisms underlying these structural changes remain largely unknown. We have previously identified M6a as a stress responsive gene and shown that M6a is involved in filopodium/spine outgrowth and, likely, synapse formation. M6a belongs to the proteolipid protein (PLP) family, all of their members having four transmembrane domains that allow their localization at the plasma membrane. In the present work, we analyzed other members of this family, the closely related M6b as well as PLP and its splice variant DM20. We found that chronic restraint stress in mice reduces M6b and DM20, but not PLP, mRNA levels in the hippocampus. In addition, M6b and DM20, but again not PLP, induce filopodium formation in primary cultures of hippocampal neurons. Several M6b protein isoforms were studied, all of them having similar effects except for the one lacking the transmembrane domains. Our results reveal a conserved cellular function and a stress-mediated regulation among members of the proteolipid protein family, suggesting an involvement of proteolipid proteins in the stress response. © 2009 Wiley-Liss, Inc. [source] Bcl-3 is an interleukin-1,responsive gene in chondrocytes and synovial fibroblasts that activates transcription of the matrix metalloproteinase 1 geneARTHRITIS & RHEUMATISM, Issue 12 2002Sarah F. Elliott Objective To define the role of Bcl-3, a member of the inhibitor of nuclear factor ,B (NF-,B) family and a known regulator of NF-,B, in interleukin-1 (IL-1),induced matrix metalloproteinase 1 (MMP-1) transcription in chondrocytes and synovial fibroblasts. Methods SW-1353 cells, a human chondrosarcoma cell line, were stimulated with IL-1,, and the harvested RNA was subjected to microarray analysis and quantitative real-time reverse transcription,polymerase chain reaction (RT-PCR). The SW-1353 cells were stimulated with IL-1 or transfected with a plasmid that constitutively expressed Bcl-3, and then MMP-1 messenger RNA (mRNA) expression was assayed by quantitative real-time RT-PCR. SW-1353 cells were transfected with antisense oligonucleotides to Bcl-3, and IL-1,induced MMP-1 mRNA expression was assayed by quantitative RT-PCR. SW-1353 cells and rabbit synovial fibroblasts were transfected with a 4.3-kb human MMP-1 promoter construct along with Bcl-3 and NF-,B1 expression constructs, and MMP-1 transcription was assayed. Results Microarray analysis and real-time RT-PCR showed Bcl-3 to be an IL-1,,responsive gene in SW-1353 cells. Exogenous expression of Bcl-3 in SW-1353 cells activated MMP-1 transcription. Endogenous Bcl-3 expression was required for IL-1, induction of MMP-1 gene expression. Bcl-3 also activated MMP-1 transcription in primary synovial fibroblasts. We showed previously that NF-,B1 contributes to IL-1, induction of MMP-1 transcription in stromal cells. We showed here that Bcl-3 can cooperate with NF-,B1 to activate MMP-1 transcription in SW-1353 cells. Conclusion These data define a new role for Bcl-3 in joint cells as an IL-1,,responsive early gene involved in cell-mediated cartilage remodeling. Our findings implicate Bcl-3 as an important contributor to chronic inflammatory disease states, such as osteoarthritis and rheumatoid arthritis. [source] Developmental toxicity of estrogenic chemicals on rodents and other speciesCONGENITAL ANOMALIES, Issue 2 2002Taisen Iguchi ABSTRACT, Antenatal sex-hormone exposure induces lesions in mouse reproductive organs, which are similar to those in humans exposed in utero to a synthetic estrogen, diethylstilbestrol. The developing organisms including rodents, fish and amphibians are particularly sensitive to exposure to estrogenic chemicals during a critical window. Exposure to estrogens during the critical period induces long-term changes in reproductive as well as non-reproductive organs, including persistent molecular alterations. The antenatal mouse model can be utilized as an indicator of possible long-term consequences of exposure to exogenous estrogenic compounds including possible environmental endocrine disrupters. Many chemicals released into the environment potentially disrupt the endocrine system in wildlife and humans, some of which exhibit estrogenic activity by binding to the estrogen receptors. Estrogen responsive genes, therefore, need to be identified to understand the molecular basis of estrogenic actions. In order to understand molecular mechanisms of estrogenic chemicals on developing organisms, we are identifying estrogen responsive genes using cDNA microarray, quantitative RT-PCR, and differential display methods, and genes related to the estrogen-independent vaginal changes in mice induced by estrogens during the critical window. In this review, discussion of our own findings related to endocrine distuptor issue will be provided. [source] Evaluation of estrogenic activity of phthalate esters by gene expression profiling using a focused microarray (estrarray®),ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 6 2008Meher Parveen Abstract Phthalates are used industrially as plasticizers and are known to contaminate natural environments, mostly as di-ester or mono-ester complexes. Because they are structurally similar to natural estrogens, they could act as endocrine disruptors. Here, we used a DNA microarray containing estrogen responsive genes (EstrArray®) to examine gene expression profiles in MCF-7 cells treated with 10 ,M butylbenzyl phthalate (BBP), dibutyl phthalate (DBP), diethyl phthalate (DEP), and diisopropyl phthalate (DIP) along with the natural estrogen 17,-estradiol ([E2], 10 nM). The profiles for phthalate esters and E2 were examined by correlation analysis using correlation coefficients (r -values) and cluster analysis. We found that BBP showed the highest correlation with E2 (r = 0.85), and DEP and DIP showed moderate r -values (r = 0.52 and r = 0.49, respectively). Dibutyl phthalate exhibited the lowest (but still significant) correlation with E2 (r = 0.36). Furthermore, among the pairs of chemicals, DEP-DIP and DIP-DBP showed very high correlations (r = 0.90 and r = 0.80, respectively), and the other pairs showed moderate relationships, which reflected how structurally close they are to each other. The analysis of six functional groups of genes (enzymes, signaling, proliferation, transcription, transport, and others) indicated that the genes belonging to the enzyme, transcription, and other functional groups showed common responses to phthalate esters and E2. Although the effect of BBP was similar to that of E2, the other phthalate esters showed different types of effects. These results indicate that the structure of estrogenic chemicals is strongly related to their estrogenic activity and can be evaluated by appropriate grouping of the responsive genes by focused microarray analysis. [source] Expression of immune responsive genes in cell lines from two different Anopheline speciesINSECT MOLECULAR BIOLOGY, Issue 6 2006C. Luna Abstract Malaria infection results in increased expression of immune responsive genes, including those encoding antimicrobial peptides such as Gambicin (Gam1) and Cecropin A (Cec1). Understanding how these genes are regulated will provide insights how the mosquito immune system is activated by Plasmodium. We previously have shown that Cec1 was primarily regulated by the Imd-Relish (REL2) pathway in the Anopheles gambiae Sua1B cell line. We show here that expression of Defensin A (Def1) and Gam1 was reduced after RNA interference against components of the Imd- REL2 pathway in An. gambiae cell lines. Interestingly, promoter reporters of these antimicrobial peptides were expressed at very low level in the cell line MSQ43 from Anopheles stephensi. Surprisingly, over-expression of either NF-,B transcription factor REL1 or REL2 alone is sufficient to induce the expression of Cec1, Gam1 and Def1. These results suggest that expression of these antimicrobial peptides (AMP) in vivo may be regulated by both the Toll and Imd pathways. We also show here for the first time that Tep4, a gene encoding a thioester containing protein, is regulated by REL2. Taken together, these results suggest that there are significant overlaps of genes regulated by the Toll-Rel1 and Imd-Rel2 pathways. Further, the different expression patterns in two different Anopheline cell lines provide a platform to identify other key positive and negative regulators of the antimicrobial peptide genes. [source] Dysregulated BMP Signaling and Enhanced Osteogenic Differentiation of Connective Tissue Progenitor Cells From Patients With Fibrodysplasia Ossificans Progressiva (FOP),JOURNAL OF BONE AND MINERAL RESEARCH, Issue 3 2008Paul C Billings Abstract The study of FOP, a disabling genetic disorder of progressive heterotopic ossification, is hampered by the lack of readily available connective tissue progenitor cells. We isolated such cells from discarded primary teeth of patients with FOP and controls and discovered dysregulation of BMP signaling and rapid osteoblast differentiation in FOP cells compared with control cells. Introduction: Fibrodysplasia ossificans progressiva (FOP), the most disabling condition of progressive heterotopic ossification in humans, is caused by a recurrent heterozygous missense mutation in activin receptor IA (ACVR1), a bone morphogenetic protein (BMP) type I receptor, in all classically affected individuals. A comprehensive understanding of FOP has been limited, in part, by a lack of readily available connective tissue progenitor cells in which to study the molecular pathology of this disorder. Materials and Methods: We derived connective tissue progenitor cells from discarded primary teeth (SHED cells) of patients with FOP and controls and examined BMP signaling and osteogenic differentiation in these cells. Results: SHED cells transmitted BMP signals through both the SMAD and p38 mitogen-activated protein kinase (MAPK) pathways and responded to BMP4 treatment by inducing BMP responsive genes. FOP cells showed ligand-independent BMP signaling and ligand-dependent hyper-responsiveness to BMP stimulation. Furthermore, FOP cells showed more rapid differentiation to an osteogenic phenotype than control cells. Conclusions: This is the first study of BMP signaling and osteogenic differentiation in connective tissue progenitor cells from patients with FOP. Our data strongly support both basal and ligand-stimulated dysregulation of BMP signaling consistent with in silico studies of the mutant ACVR1 receptor in this condition. This study substantially extends our understanding of dysregulated BMP signaling in a progenitor cell population relevant to the pathogenesis of this catastrophic disorder of progressive ectopic ossification. [source] Selective induction of mucin-3 by hypoxia in intestinal epitheliaJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 6 2006Nancy A. Louis Abstract Epithelial cells line mucosal surfaces (e.g., lung, intestine) and critically function as a semipermeable barrier to the outside world. Mucosal organs are highly vascular with extensive metabolic demands, and for this reason, are particularly susceptible to diminished blood flow and resultant tissue hypoxia. Here, we pursue the hypothesis that intestinal barrier function is regulated in a protective manner by hypoxia responsive genes. We demonstrate by PCR confirmation of microarray data and by avidin blotting of immunoprecipitated human Mucin 3 (MUC3), that surface MUC3 expression is induced in T84 intestinal epithelial cells following exposure to hypoxia. MUC3 RNA is minimally detectable while surface protein expression is absent under baseline normoxic conditions. There is a robust induction in both the mRNA (first evident by 8 h) and protein expression, first observed and maximally expressed following 24 h hypoxia. This is followed by a subsequent decline in protein expression, which remains well above baseline at 48 h of hypoxia. Further, we demonstrate that this induction of MUC3 protein is associated with a transient increase in the barrier restorative peptide, intestinal trefoil factor (ITF). ITF not only colocalizes with MUC3, by confocal microscopy, to the apical surface of T84 cells following exposure to hypoxia, but is also found, by co-immunoprecipitation, to be physically associated with MUC3, following 24 h of hypoxia. In exploration of the mechanism of hypoxic regulation of mucin 3 expression, we demonstrated by luciferase assay that the full-length promoter for mouse Mucin 3 (Muc3) is hypoxia-responsive with a 5.08,±,1.76-fold induction following 24 h of hypoxia. Furthermore, analysis of both the human (MUC3A) and mouse (Muc3) promoters revealed potential HIF-1 binding sites which were shown by chromatin immunoprecipitation to bind the pivotal hypoxia-regulating transcription factor HIF-1,. Taken together, these studies implicate the HIF-1, mediated hypoxic induced expression of mucin 3 and associated ITF in the maintenance of intestinal barrier function under hypoxic conditions. J. Cell. Biochem. 99: 1616,1627, 2006. © 2006 Wiley-Liss, Inc. [source] Acute Activation of Hippocampal Glucocorticoid Receptors Results in Different Waves of Gene Expression Throughout TimeJOURNAL OF NEUROENDOCRINOLOGY, Issue 4 2006M. C. Morsink Abstract Several aspects of hippocampal cell function are influenced by adrenal-secreted glucocorticoids in a delayed, genomic fashion. Previously, we used Serial Analysis of Gene Expression to identify glucocorticoid receptor (GR)-induced transcriptional changes in the hippocampus at a fixed time point. However, because changes in mRNA levels are transient and most likely precede the effects on hippocampal cell function, the aim of the current study was to assess the transcriptional changes in a broader time window by generating a time curve of GR-mediated gene expression changes. Therefore, we used rat hippocampal slices obtained from adrenalectomised rats, substituted in vivo with low corticosterone pellets, predominantly occupying the hippocampal mineralocorticoid receptors. To activate GR, slices were treated in vitro with a high (100 nM) dose of corticosterone and gene expression was profiled 1, 3 and 5 h after GR-activation. Using Affymetrix GeneChips, a striking pattern with different waves of gene expression was observed, shifting from exclusively down-regulated genes 1 h after GR-activation to both up and down regulated genes 3 h after GR-activation. After 5 h, the response was almost back to baseline. Additionally, real-time quantitative polymerase chain reaction was used for validation of a selection of responsive genes including genes involved in neurotransmission and synaptic plasticity such as the corticotropin releasing hormone receptor 1, monoamine oxidase A, LIMK1 and calmodulin 2. This permitted confirmation of GR-responsiveness of 15 out of 18 selected genes. In conclusion, direct activation of GR in hippocampal slices results in transient changes in gene expression. The pattern in which gene expression was modulated suggests that the fast genomic effects of glucocorticoids may be realised via transrepression, preceding a later wave of transactivation. Furthermore, we identified a number of interesting candidate genes which may underlie the glucocorticoid-mediated effects on hippocampal cell function. [source] Regulation of oxidative-stress responsive genes by arecoline in human keratinocytesJOURNAL OF PERIODONTAL RESEARCH, Issue 5 2009G. S. Thangjam Background and Objective:, Arecoline, an arecanut alkaloid present in the saliva of betel quid chewers, has been implicated in the pathogenesis of a variety of inflammatory oral diseases, including oral submucous fibrosis and periodontitis. To understand the molecular basis of arecoline action in epithelial changes associated with these diseases, we investigated the effects of arecoline on human keratinocytes with respect to cell growth regulation and the expression of stress-responsive genes. Material and Methods:, Human keratinocyte cells (of the HaCaT cell line) were treated with arecoline, following which cell viability was assessed using the Trypan Blue dye-exclusion assay, cell growth and proliferation were analyzed using the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) and 5-bromo-2-deoxyuridine incorporation assays, cell cycle arrest and generation of reactive oxygen species were examined using flow cytometry, and gene expression changes were investigated using the reverse transcription,polymerase chain reaction technique. The role of oxidative stress, muscarinic acetylcholine receptor and mitogen-activated protein kinase (MAPK) pathways were studied using specific inhibitors. Western blot analysis was performed to study p38 MAPK activation. Results:, Arecoline induced the generation of reactive oxygen species and cell cycle arrest at the G1/G0 phase in HaCaT cells without affecting the expression of p21/Cip1. Arecoline-induced epithelial cell death at higher concentrations was caused by oxidative trauma without eliciting apoptosis. Sublethal concentrations of arecoline upregulated the expression of the following stress-responsive genes: heme oxygenase-1; ferritin light chain; glucose-6-phosphate dehydrogenase; glutamate-cysteine ligase catalytic subunit; and glutathione reductase. Additionally, there was a dose-dependent induction of interleukin-1alfa mRNA by arecoline via oxidative stress and p38 MAPK activation. Conclusion:, Our data highlight the role of oxidative stress in arecoline-mediated cell death, gene regulation and inflammatory processes in human keratinocytes. [source] Expression patterns of low temperature responsive genes in a dominant ABA-less-sensitive mutant line of common wheatPHYSIOLOGIA PLANTARUM, Issue 4 2006Fuminori Kobayashi Abscisic acid (ABA) plays important role in mediating stress responses and in acquiring desiccation tolerance and dormancy of plant seeds. To study roles of ABA in cold acclimation and freezing tolerance in wheat, expression profiles of Cor/Lea and their putative transcription factor (TF) genes were analysed using a dominant mutation line of common wheat EH47-1 lacking seed dormancy. The mutant line was less sensitive to exogenous ABA than the original line as judged by the magnitude of ABA inhibition of seedling growth. Expression analysis of Cor/Lea and TF genes however, showed that more transcripts were present in ABA-treated seedlings of the mutant line. In developing caryopses, the same tendency was observed. The mutant line showed no changes in the cold acclimation ability, but it showed a higher level of freezing tolerance than the original line without cold acclimation. No significant differences were observed in the expression profiles of Cor/Lea and TF genes during cold acclimation between the two lines. Our results imply the presence of an unknown ABA-dependent cold responsive pathway, which enhances the basal level of freezing tolerance by a dominant mutation in EH47-1. [source] Functional analysis of rice NPR1 -like genes reveals that OsNPR1/NH1 is the rice orthologue conferring disease resistance with enhanced herbivore susceptibility,PLANT BIOTECHNOLOGY JOURNAL, Issue 2 2007Yuexing Yuan Summary The key regulator of salicylic acid (SA)-mediated resistance, NPR1, is functionally conserved in diverse plant species, including rice (Oryza sativa L.). Investigation in depth is needed to provide an understanding of NPR1 -mediated resistance and a practical strategy for the improvement of disease resistance in the model crop rice. The rice genome contains five NPR1 -like genes. In our study, three rice homologous genes, OsNPR1/NH1, OsNPR2/NH2 and OsNPR3, were found to be induced by rice bacterial blight Xanthomonas oryzae pv. oryzae and rice blast Magnaporthe grisea, and the defence molecules benzothiadiazole, methyl jasmonate and ethylene. We confirmed that OsNPR1 is the rice orthologue by complementing the Arabidopsis npr1 mutant. Over-expression of OsNPR1 conferred disease resistance to bacterial blight, but also enhanced herbivore susceptibility in transgenic plants. The OsNPR1-green fluorescent protein (GFP) fusion protein was localized in the cytoplasm and moved into the nucleus after redox change. Mutations in its conserved cysteine residues led to the constitutive localization of OsNPR1(2CA)-GFP in the nucleus and also abolished herbivore hypersensitivity in transgenic rice. Different subcellular localizations of OsNPR1 antagonistically regulated SA- and jasmonic acid (JA)-responsive genes, but not SA and JA levels, indicating that OsNPR1 might mediate antagonistic cross-talk between the SA- and JA-dependent pathways in rice. This study demonstrates that rice has evolved an SA-mediated systemic acquired resistance similar to that in Arabidopsis, and also provides a practical approach for the improvement of disease resistance without the penalty of decreased herbivore resistance in rice. [source] ORIGINAL ARTICLE: TNF, Gene Silencing Reduced Lipopolysaccharide-Promoted Proliferation of Endometriotic Stromal CellsAMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 4 2009Ayako Miyamoto Problem, We previously reported that lipopolysaccharide (LPS)-promoted endometriotic stromal cell (ESC) proliferation by inducing TNF, production. The aim of this study was to investigate the efficacy of TNF, gene silencing on LPS-treated ESCs. Method of study, Endometriotic stromal cells (ESCs) and endometrial stromal cells (ESCs) (EMSCs) were obtained from ovarian chocolate cysts and uterine myoma, respectively. Using PCR array, LPS-induced gene expression profiling after transfection of TNF, siRNA into ESCs was performed. Down-regulated genes by TNF, silencing were examined using real-time RT-PCR. Effect of TNF, silencing was examined using ELISA and BrdU incorporation, respectively. Results, In PCR array, TNF, silencing in ESCs repressed LPS-induced expression of cIAP2 and IL-8, NF,B pathway responsive genes. After adding LPS, the levels of cIAP2 and IL-8 expression in ESCs were higher compared with those in EMSCs. TNF, silencing attenuated the LPS-induced ESC proliferation. Conclusion, Tumor necrosis factor , may be involved in cell proliferation of endometriotic tissues. [source] A mutation in the Arabidopsis mTERF-related plastid protein SOLDAT10 activates retrograde signaling and suppresses 1O2 -induced cell deathTHE PLANT JOURNAL, Issue 3 2009Rasa Meskauskiene Summary The conditional flu mutant of Arabidopsis thaliana generates singlet oxygen (1O2) in plastids during a dark-to-light shift. Seedlings of flu bleach and die, whereas mature plants stop growing and develop macroscopic necrotic lesions. Several suppressor mutants, dubbed singlet oxygen-linked death activator (soldat), were identified that abrogate 1O2 -mediated cell death of flu seedlings. One of the soldat mutations, soldat10, affects a gene encoding a plastid-localized protein related to the human mitochondrial transcription termination factor mTERF. As a consequence of this mutation, plastid-specific rRNA levels decrease and protein synthesis in plastids of soldat10 is attenuated. This disruption of chloroplast homeostasis in soldat10 seedlings affects communication between chloroplasts and the nucleus and leads to changes in the steady-state concentration of nuclear gene transcripts. The soldat10 seedlings suffer from mild photo-oxidative stress, as indicated by the constitutive up-regulation of stress-related genes. Even though soldat10/flu seedlings overaccumulate the photosensitizer protochlorophyllide in the dark and activate the expression of 1O2 -responsive genes after a dark-to-light shift they do not show a 1O2 -dependent cell death response. Disturbance of chloroplast homeostasis in emerging soldat10/flu seedlings seems to antagonize a subsequent 1O2 -mediated cell death response without suppressing 1O2 -dependent retrograde signaling. The results of this work reveal the unexpected complexity of what is commonly referred to as ,plastid signaling'. [source] Transcriptional regulation by an NAC (NAM,ATAF1,2,CUC2) transcription factor attenuates ABA signalling for efficient basal defence towards Blumeria graminis f. sp. hordei in ArabidopsisTHE PLANT JOURNAL, Issue 6 2008Michael K. Jensen Summary ATAF1 is a member of a largely uncharacterized plant-specific gene family encoding NAC transcription factors, and is induced in response to various abiotic and biotic stimuli in Arabidopsis thaliana. Previously, we showed that a mutant allele of ATAF1 compromises penetration resistance in Arabidopsis with respect to the non-host biotrophic pathogen Blumeria graminis f. sp. hordei (Bgh). In this study, we have used genome-wide transcript profiling to characterize signalling perturbations in ataf1 plants following Bgh inoculation. Comparative transcriptomic analyses identified an over-representation of abscisic acid (ABA)-responsive genes, including the ABA biosynthesis gene AAO3, which is significantly induced in ataf1 plants compared to wild-type plants following inoculation with Bgh. Additionally, we show that Bgh inoculation results in decreased endogenous ABA levels in an ATAF1 -dependent manner, and that the ABA biosynthetic mutant aao3 showed increased penetration resistance to Bgh compared to wild-type plants. Furthermore, we show that ataf1 plants show ABA-hyposensitive phenotypes during seedling development and germination. Our data support a negative correlation between ABA levels and penetration resistance, and identify ATAF1 as a new stimuli-dependent attenuator of ABA signalling for the mediation of efficient penetration resistance in Arabidopsis upon Bgh attack. [source] WRKY70 modulates the selection of signaling pathways in plant defenseTHE PLANT JOURNAL, Issue 3 2006Jing Li Summary Cross-talk between signal transduction pathways is a central feature of the tightly regulated plant defense signaling network. The potential synergism or antagonism between defense pathways is determined by recognition of the type of pathogen or pathogen-derived elicitor. Our studies have identified WRKY70 as a node of convergence for integrating salicylic acid (SA)- and jasmonic acid (JA)-mediated signaling events during plant response to bacterial pathogens. Here, we challenged transgenic plants altered in WRKY70 expression as well as WRKY70 knockout mutants of Arabidopsis with the fungal pathogens Alternaria brassicicola and Erysiphe cichoracearum to elucidate the role of WRKY70 in modulating the balance between distinct defense responses. Gain or loss of WRKY70 function causes opposite effects on JA-mediated resistance to A. brassicicola and the SA-mediated resistance to E. cichoracearum. While the up-regulation of WRKY70 caused enhanced resistance to E. cichoracearum, it compromised plant resistance to A. brassicicola. Conversely, down-regulation or insertional inactivation of WRKY70 impaired plant resistance to E. cichoracearum. Over-expression of WRKY70 resulted in the suppression of several JA responses including expression of a subset of JA- and A. brassicicola -responsive genes. We show that this WRKY70 -controlled suppression of JA-signaling is partly executed by NPR1. The results indicate that WRKY70 has a pivotal role in determining the balance between SA-dependent and JA-dependent defense pathways. [source] ABA activates ADPR cyclase and cADPR induces a subset of ABA-responsive genes in ArabidopsisTHE PLANT JOURNAL, Issue 3 2004Juan-Pablo Sánchez Summary Cyclic ADP-ribose (cADPR) was previously shown to activate transient expression of two abscisic acid (ABA)-responsive genes in tomato cells. Here, we show that the activity of the enzyme responsible for cADPR synthesis, ADP-ribosyl (ADPR) cyclase, is rapidly induced by ABA in both wild-type (WT) and abi1-1 mutant Arabidopsis plants in the absence of protein synthesis. Furthermore, in transgenic Arabidopsis plants, induced expression of the Aplysia ADPR cyclase gene resulted in an increase in ADPR cyclase activity and cADPR levels, as well as elevated expression of ABA-responsive genes KIN2, RD22, RD29a, and COR47 (although to a lesser extent than after ABA induction). Genome-wide profiling indicated that about 28% of all ABA-responsive genes in Arabidopsis are similarly up- and downregulated by cADPR and contributed to the identification of new ABA-responsive genes. Our results suggest that activation of ADPR cyclase is an early ABA-signaling event partially insensitive to the abi1-1 mutation and that an increase in cADPR plays an important role in downstream molecular and physiological ABA responses. [source] Interleukin-4 activates androgen receptor through CBP/p300THE PROSTATE, Issue 2 2009Soo Ok Lee Abstract BACKGROUND Aberrant activation of androgen receptor (AR) plays an important role in the progression of castration resistant prostate cancer. Interleukin-4 (IL-4) enhances AR activation in the absence of androgen and stimulates castration resistant growth of androgen-sensitive prostate cancer cells. However, the mechanism of IL-4 mediated AR activation has not yet been revealed. METHODS The effect of IL-4 on CBP/p300 expression was examined by Western blot analysis. The effect of IL-4 on the interactions of AR and CBP/p300 was examined by co-immunoprecipitation and ChIP assays. CBP/p300 siRNA was used to knockdown CBP/p300 expression to examine the role of CBP/p300 expression on IL-4 mediated AR activation. RESULTS We found that IL-4 increases CBP/p300 protein expression and enhances interaction of AR with CBP/p300 proteins through an increase in the recruitment of CBP/p300 protein to the androgen responsive elements in the promoters of androgen responsive genes. Down regulation of CBP/p300 expression using CBP/p300 specific siRNA abolished IL-4 mediated AR activation, suggesting that CBP/p300 is responsible for AR activation induced by IL-4. Furthermore, AR activation can be enhanced by AR acetylation induced by IL-4 in prostate cancer cells. The IL-4 mediated AR acetylation can be blocked by knocking down CBP/p300 expression using CBP/p300 specific siRNA. CONCLUSION These results suggest that IL-4 activates AR through enhanced expression of CBP/p300 and its histone acetyltransferase activity. Prostate 69: 126,132, 2009. © 2008 Wiley,Liss, Inc. [source] Analysis of vitamin D-regulated gene expression in LNCaP human prostate cancer cells using cDNA microarraysTHE PROSTATE, Issue 3 2004Aruna V. Krishnan Abstract BACKGROUND 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] exerts growth inhibitory, pro-differentiating, and pro-apoptotic effects on prostate cells. To better understand the molecular mechanisms underlying these actions, we employed cDNA microarrays to study 1,25(OH)2D3 -regulated gene expression in the LNCaP human prostate cancer cells. METHODS mRNA isolated from LNCaP cells treated with vehicle or 50 nM 1,25(OH)2D3 for various lengths of time were hybridized to microarrays carrying approximately 23,000 genes. Some of the putative target genes revealed by the microarray analysis were verified by real-time PCR assays. RESULTS 1,25(OH)2D3 most substantially increased the expression of the insulin-like growth factor binding protein-3 (IGFBP-3) gene. Our analysis also revealed several novel 1,25(OH)2D3 -responsive genes. Interestingly, some of the key genes regulated by 1,25(OH)2D3 are also androgen-responsive genes. 1,25(OH)2D3 also down-regulated genes that mediate androgen catabolism. CONCLUSIONS The putative 1,25(OH)2D3 target genes appear to be involved in a variety of cellular functions including growth regulation, differentiation, membrane transport, cell,cell and cell,matrix interactions, DNA repair, and inhibition of metastasis. The up-regulation of IGFBP-3 gene has been shown to be crucial in 1,25(OH)2D3 -mediated inhibition of LNCaP cell growth. 1,25(OH)2D3 regulation of androgen-responsive genes as well as genes involved in androgen catabolism suggests that there are interactions between 1,25(OH)2D3 and androgen signaling pathways in LNCaP cells. Further studies on the role of these genes and others in mediating the anti-cancer effects of 1,25(OH)2D3 may lead to better approaches to the prevention and treatment of prostate cancer. © 2004 Wiley-Liss, Inc. [source] The influence of extracellular matrix and prolactin on global gene expression profiles of primary bovine mammary epithelial cells in vitroANIMAL GENETICS, Issue 1 2010L. G. Riley Summary An in vitro bovine mammosphere model was characterized for use in lactational biology studies using a functional genomics approach. Primary bovine mammary epithelial cells cultured on a basement membrane, Matrigel, formed three-dimensional alveoli-like structures or mammospheres. Gene expression profiling during mammosphere formation by high-density microarray analysis indicated that mammospheres underwent similar molecular and cellular processes to developing alveoli in the mammary gland. Gene expression profiles indicated that genes involved in milk protein and fat biosynthesis were expressed, however, lactose biosynthesis may have been compromised. Investigation of factors influencing mammosphere formation revealed that extracellular matrix (ECM) was responsible for the initiation of this process and that prolactin (Prl) was necessary for high levels of milk protein expression. CSN3 (encoding ,-casein) was the most highly expressed casein gene, followed by CSN1S1 (encoding ,S1-casein) and CSN2 (encoding ,-casein). Eighteen Prl-responsive genes were identified, including CSN1S1, SOCS2 and CSN2, however, expression of CSN3 was not significantly increased by Prl and CSN1S2 was not expressed at detectable levels in mammospheres. A number of novel Prl responsive genes were identified, including ECM components and genes involved in differentiation and apoptosis. This mammosphere model is a useful model system for functional genomics studies of certain aspects of dairy cattle lactation. [source] | |||||||||||||