scholarly journals FixJ: a Major Regulator of the Oxygen Limitation Response and Late Symbiotic Functions of Sinorhizobium meliloti

2006 ◽  
Vol 188 (13) ◽  
pp. 4890-4902 ◽  
Author(s):  
Christine Bobik ◽  
Eliane Meilhoc ◽  
Jacques Batut
Keyword(s):  
Sinorhizobium Meliloti ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Regulatory System ◽  
Polyamine Metabolism ◽  
Nitrogen Fixing ◽  
Low Oxygen ◽  
Free Living ◽  
Expression Of Genes ◽  
Oxygen Conditions

ABSTRACT Sinorhizobium meliloti exists either in a free-living state in the soil or in symbiosis within legume nodules, where the bacteria differentiate into nitrogen-fixing bacteroids. Expression of genes involved in nitrogen fixation and associated respiration is governed by two intermediate regulators, NifA and FixK, respectively, which are controlled by a two-component regulatory system FixLJ in response to low-oxygen conditions. In order to identify the FixLJ regulon, gene expression profiles were determined in microaerobic free-living cells as well as during the symbiotic life of the bacterium for the wild type and a fixJ null-mutant strain. We identified 122 genes activated by FixJ in either state, including 87 novel targets. FixJ controls 74% of the genes induced in microaerobiosis (2% oxygen) and the majority of genes expressed in mature bacteroids. Ninety-seven percent of FixJ-activated genes are located on the symbiotic plasmid pSymA. Transcriptome profiles of a nifA and a fixK mutant showed that NifA activates a limited number of genes, all specific to the symbiotic state, whereas FixK controls more than 90 genes, involved in free-living and/or symbiotic life. This study also revealed that FixJ has no other direct targets besides those already known. FixJ is involved in the regulation of functions such as denitrification or amino acid/polyamine metabolism and transport. Mutations in selected novel FixJ targets did not affect the ability of the bacteria to form nitrogen-fixing nodules on Medicago sativa roots. From these results, we propose an updated model of the FixJ regulon.

scholarly journals Global Changes in Gene Expression in Sinorhizobium meliloti 1021 under Microoxic and Symbiotic Conditions

2004 ◽  
Vol 17 (3) ◽  
pp. 292-303 ◽  
Author(s):  
Anke Becker ◽  
Hélène Bergès ◽  
Elizaveta Krol ◽  
Claude Bruand ◽  
Silvia Rüberg ◽  
...  
Keyword(s):  
Gene Expression ◽  
Sinorhizobium Meliloti ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Transcriptome Profiling ◽  
Global Changes ◽  
Limited Extent ◽  
Free Living ◽  
Symbiotic Gene ◽  
Number Of Genes

Sinorhizobium meliloti is an α-proteobacterium that alternates between a free-living phase in bulk soil or in the rhizosphere of plants and a symbiotic phase within the host plant cells, where the bacteria ultimately differentiate into nitrogen-fixing organelle-like cells, called bacteroids. As a step toward understanding the physiology of S. meliloti in its free-living and symbiotic forms and the transition between the two, gene expression profiles were determined under two sets of biological conditions: growth under oxic versus microoxic conditions, and in free-living versus symbiotic state. Data acquisition was based on both macro- and microarrays. Transcriptome profiles highlighted a profound modification of gene expression during bacteroid differentiation, with 16% of genes being altered. The data are consistent with an overall slow down of bacteroid metabolism during adaptation to symbiotic life and acquisition of nitrogen fixation capability. A large number of genes of unknown function, including potential regulators, that may play a role in symbiosis were identified. Transcriptome profiling in response to oxygen limitation indicated that up to 5% of the genes were oxygen regulated. However, the microoxic and bacteroid transcriptomes only partially overlap, implying that oxygen contributes to a limited extent to the control of symbiotic gene expression.

scholarly journals Connectivity Map Analysis Indicates PI3K/Akt/mTOR Inhibitors as Potential Anti-Hypoxia Drugs in Neuroblastoma

Cancers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2809
Author(s):  
Paolo Uva ◽  
Maria Carla Bosco ◽  
Alessandra Eva ◽  
Massimo Conte ◽  
Alberto Garaventa ◽  
...  
Keyword(s):  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Drug Repurposing ◽  
Enrichment Analysis ◽  
Mtor Inhibitors ◽  
Gene Set Enrichment Analysis ◽  
Low Oxygen ◽  
Connectivity Map ◽  
Hypoxic Conditions ◽  
Connectivity Score

Neuroblastoma (NB) is one of the deadliest pediatric cancers, accounting for 15% of deaths in childhood. Hypoxia is a condition of low oxygen tension occurring in solid tumors and has an unfavorable prognostic factor for NB. In the present study, we aimed to identify novel promising drugs for NB treatment. Connectivity Map (CMap), an online resource for drug repurposing, was used to identify connections between hypoxia-modulated genes in NB tumors and compounds. Two sets of 34 and 21 genes up- and down-regulated between hypoxic and normoxic primary NB tumors, respectively, were analyzed with CMap. The analysis reported a significant negative connectivity score across nine cell lines for 19 compounds mainly belonging to the class of PI3K/Akt/mTOR inhibitors. The gene expression profiles of NB cells cultured under hypoxic conditions and treated with the mTORC complex inhibitor PP242, referred to as the Mohlin dataset, was used to validate the CMap findings. A heat map representation of hypoxia-modulated genes in the Mohlin dataset and the gene set enrichment analysis (GSEA) showed an opposite regulation of these genes in the set of NB cells treated with the mTORC inhibitor PP242. In conclusion, our analysis identified inhibitors of the PI3K/Akt/mTOR signaling pathway as novel candidate compounds to treat NB patients with hypoxic tumors and a poor prognosis.

scholarly journals Expression of sugarcane genes induced by inoculation with Gluconacetobacter diazotrophicus and Herbaspirillum rubrisubalbicans

2001 ◽  
Vol 24 (1-4) ◽  
pp. 199-206 ◽  
Author(s):  
Eduardo de Matos Nogueira ◽  
Fabiano Vinagre ◽  
Hana Paula Masuda ◽  
Claudia Vargas ◽  
Vânia Lúcia Muniz de Pádua ◽  
...  
Keyword(s):  
Expressed Sequence Tag ◽  
Expression Profiles ◽  
Inorganic Nitrogen ◽  
Gene Expression Profiles ◽  
Nitrogen Fertilizers ◽  
Gluconacetobacter Diazotrophicus ◽  
Nitrogen Fixing ◽  
Preferential Expression ◽  
Sugarcane Varieties ◽  
Exclusive Or

Several Brazilian sugarcane varieties have the ability to grow with little addition of inorganic nitrogen fertilizers, showing high contributions of Biological Nitrogen Fixation (BNF). A particular type of nitrogen-fixing association has been described in this crop, where endophytic diazotrophs such as Gluconacetobacter diazotrophicus and Herbaspirillum spp. colonize plant tissues without causing disease symptoms. In order to gain insight into the role played by the sugarcane in the interaction between this plant and endophytic diazotrophs, we investigated gene expression profiles of sugarcane plants colonized by G. diazotrophicus and H. rubrisubalbicans by searching the sugarcane expressed sequence tag SUCEST Database (<A HREF="http://sucest.lad.ic.unicamp.br/en/">http://sucest.lad.ic.unicamp.br/en/</A>). We produced an inventory of sugarcane genes, candidates for exclusive or preferential expression during the nitrogen-fixing association. This data suggests that the host plant might be actively involved in the establishment of the interaction with G. diazotrophicus and H. rubrisubalbicans.

scholarly journals Viral fitness predicts the magnitude and direction of perturbations in the infected host transcriptome

2017 ◽  
Author(s):  
Héctor Cervera ◽  
Silvia Ambrós ◽  
Guillermo P. Bernet ◽  
Guillermo Rodrigo ◽  
Santiago F. Elena
Keyword(s):  
Rna Silencing ◽  
Regulatory Networks ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Viral Fitness ◽  
Evolutionary Potential ◽  
Expression Of Genes ◽  
Darwinian Fitness ◽  
Functional Classes ◽  
Host Genes

Determining the fitness of viral genotypes has become a standard practice in virology as it is essential to evaluate their evolutionary potential. Darwinian fitness, defined as the advantage of a given genotype with respect to a reference one, is a mesoscopic property that captures into a single figure differences in performance at every stage of viral infection. But to which extent viral fitness results from particular molecular interactions with host factors and regulatory networks during infection? Can we identify host genes, and then functional classes, whose expression depends on viral fitness? Here, we compared the transcriptomes of tobacco plants infected with seven genotypes of tobacco etch potyvirus (TEV) that differ in fitness. We found that the larger the fitness differences among genotypes, the more dissimilar the transcriptomic profiles are. Consistently, two different mutations, one in the viral RNA polymerase and another in the viral suppressor of RNA silencing, that led to close fitness values, also resulted in significantly similar gene expression profiles. Moreover, we identified host genes whose expression showed a significant correlation, positive or negative, with TEV fitness. Over-expression of genes with positive correlation activates hormone-and RNA silencing-mediated pathways of plant defense. By contrast, under-expression of genes negatively correlated reduces metabolism, growth, and development. Overall, these results reveal the high information content of viral fitness, and suggest its potential use to predict differences in genomic profiles of infected hosts.

scholarly journals Premature differentiation of nephron progenitor cell and dysregulation of gene pathways critical to kidney development in a model of preterm birth

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Aleksandra Cwiek ◽  
Masako Suzuki ◽  
Kimberly deRonde ◽  
Mark Conaway ◽  
Kevin M. Bennett ◽  
...  
Keyword(s):  
Preterm Birth ◽  
Progenitor Cells ◽  
Kidney Development ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Neonatal Morbidity ◽  
Expression Of Genes ◽  
Nephron Progenitor ◽  
Lower Expression ◽  
Nephrogenic Zone

AbstractPreterm birth is a leading cause of neonatal morbidity. Survivors have a greater risk for kidney dysfunction and hypertension. Little is known about the molecular changes that occur in the kidney of individuals born preterm. Here, we demonstrate that mice delivered two days prior to full term gestation undergo premature cessation of nephrogenesis, resulting in a lower glomerular density. Kidneys from preterm and term groups exhibited differences in gene expression profiles at 20- and 27-days post-conception, including significant differences in the expression of fat-soluble vitamin-related genes. Kidneys of the preterm mice exhibited decreased proportions of endothelial cells and a lower expression of genes promoting angiogenesis compared to the term group. Kidneys from the preterm mice also had altered nephron progenitor subpopulations, early Six2 depletion, and altered Jag1 expression in the nephrogenic zone, consistent with premature differentiation of nephron progenitor cells. In conclusion, preterm birth alone was sufficient to shorten the duration of nephrogenesis and cause premature differentiation of nephron progenitor cells. These candidate genes and pathways may provide targets to improve kidney health in preterm infants.

Monitoring expression of genes involved in drug metabolism and toxicology using DNA microarrays

2001 ◽  
Vol 5 (4) ◽  
pp. 161-170 ◽  
Author(s):  
DAVID GERHOLD ◽  
MEIQING LU ◽  
JIAN XU ◽  
CHRISTOPHER AUSTIN ◽  
C. THOMAS CASKEY ◽  
...  
Keyword(s):  
Gene Expression ◽  
Drug Metabolism ◽  
Stress Responses ◽  
Dna Microarrays ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Metabolic Effects ◽  
Microarray Technology ◽  
Drug Candidates ◽  
Expression Of Genes

Oligonucleotide DNA microarrays were investigated for utility in measuring global expression profiles of drug metabolism genes. This study was performed to investigate the feasibility of using microarray technology to minimize the long, expensive process of testing drug candidates for safety in animals. In an evaluation of hybridization specificity, microarray technology from Affymetrix distinguished genes up to a threshold of ∼90% DNA identity. Oligonucleotides representing human cytochrome P-450 gene CYP3A5 showed heterologous hybridization to CYP3A4 and CYP3A7 RNAs. These genes could be clearly distinguished by selecting a subset of oligonucleotides that hybridized selectively to CYP3A5. Further validation of the technology was performed by measuring gene expression profiles in livers of rats treated with vehicle, 3-methylcholanthrene (3MC), phenobarbital, dexamethasone, or clofibrate and by confirming data for six genes using quantitative RT-PCR. Responses of drug metabolism genes, including CYPs, epoxide hydrolases ( EHs), UDP-glucuronosyl transferases ( UGTs), glutathione sulfotransferases ( GSTs), sulfotransferases ( STs), drug transporter genes, and peroxisomal genes, to these well-studied compounds agreed well with, and extended, published observations. Additional gene regulatory responses were noted that characterize metabolic effects or stress responses to these compounds. Thus microarray technology can provide a facile overview of gene expression responses relevant to drug metabolism and toxicology.

Immune- and tumor-intrinsic gene expression profiles of response or resistance to tislelizumab as monotherapy or in combination with chemotherapy in non-small cell lung cancer (NSCLC).

2020 ◽  
Vol 38 (15_suppl) ◽  
pp. e15258-e15258
Author(s):  
Jayesh Desai ◽  
Jie Wang ◽  
Qing Zhou ◽  
Jun Zhao ◽  
Sanjeev Deva ◽  
...  
Keyword(s):  
Gene Expression ◽  
Dna Repair ◽  
Clinical Benefit ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Rank Test ◽  
M2 Macrophage ◽  
Intrinsic Factors ◽  
Expression Of Genes ◽  
Intrinsic Gene

e15258 Background: Tislelizumab, an anti-PD-1 monoclonal antibody, showed clinical benefit for patients (pts) with NSCLC alone (NCT02407990, CTR20160872) and in combination with chemotherapy (NCT03432598). Gene expression profiles (GEP) associated with response and resistance to tislelizumab in these studies were assessed. Methods: The GEP of baseline tumor samples from 59 nonsquamous (NSQ) and 42 squamous (SQ) NSCLC pts treated with tislelizumab monotherapy (mono) as ≥1L treatment, and 16 NSQ and 21 SQ pts treated with tislelizumab plus chemotherapy (combo) as 1L treatment were assessed using the 1392-gene HTG GEP EdgeSeq panel. NSQ and SQ cohorts were analyzed separately due to distinct GEP features shown by PCA and t-SNE clustering. Results: Tislelizumab mono and combo showed antitumor activity in NSCLC (Table). In 80 biomarker-evaluable samples, inflamed tumor signatures (inflammatory GEP; antigen presentation GEP) were associated with longer overall survival (log-rank test, NSQ mono: P=0.04, 0.003; NSQ combo: P=0.05, 0.02; SQ combo: P=0.06, 0.06). Monotherapy non-responders (NRs) were clustered into 2 subgroups (NR1, NR2) with distinct GEPs. Compared with responders, NR1 had proliferation signatures (elevated cell cycle [CC] and DNA repair) in both NSQ ( P=0.2, 0.02) and SQ ( P=0.03, 0.4) cohorts, trending toward low inflamed tumor signatures. In NR pts receiving combo, CC and DNA repair signatures were not enriched, and high CC and DNA repair scores were observed in some SQ combo responders versus NRs ( P=0.2, 0.02). NR2 had higher M2 macrophage and Treg cell signatures versus responders in both NSQ and SQ mono, despite high inflamed tumor and low proliferation signatures. NR2 also had increased expression of genes related to immune regulation and angiogenesis, including PIK3CD, CCR2, CD244, IRAK3, and MAP4K1 ( P<0.05) in NSQ, and PIK3CD, CCR2, CD40, CD163, MMP12, VEGFC, and TEK ( P<0.05) in SQ. Conclusions: Clinical benefit in pts with NSCLC receiving tislelizumab (mono or combo) was associated with high inflamed tumor signatures, while elevated immune suppressive cell signatures may indicate resistance. High proliferation signatures were associated with resistance to monotherapy, but not to combination therapy. Both immune- and tumor-intrinsic factors may be considered for validation in future clinical trials. [Table: see text]

scholarly journals Comparison of Host Gene Expression Profiles in Spleen Tissues of Genetically Susceptible and Resistant Mice during ECTV Infection

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Wen-Yu Cheng ◽  
Huai-Jie Jia ◽  
Xiao-Bing He ◽  
Guo-Hua Chen ◽  
Yuan Feng ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Mapk Signaling ◽  
Mouse Strains ◽  
Resistant Mouse ◽  
Gene Profiles ◽  
Expression Of Genes ◽  
Leukocyte Transendothelial Migration ◽  
Specific Virus

Ectromelia virus (ECTV), the causative agent of mousepox, has emerged as a valuable model for investigating the host-Orthopoxvirusrelationship as it relates to pathogenesis and the immune response. ECTV is a mouse-specific virus and causes high mortality in susceptible mice strains, including BALB/c and C3H, whereas C57BL/6 and 129 strains are resistant to the disease. To understand the host genetic factors in different mouse strains during the ECTV infection, we carried out a microarray analysis of spleen tissues derived from BALB/c and C57BL/6 mice, respectively, at 3 and 10 days after ECTV infection. Differential Expression of Genes (DEGs) analyses revealed distinct differences in the gene profiles of susceptible and resistant mice. The susceptible BALB/c mice generated more DEGs than the resistant C57BL/6 mice. Additionally, gene ontology and KEGG pathway analysis showed the DEGs of susceptible mice were involved in innate immunity, apoptosis, metabolism, and cancer-related pathways, while the DEGs of resistant mice were largely involved in MAPK signaling and leukocyte transendothelial migration. Furthermore, the BALB/c mice showed a strong induction of interferon-induced genes, which, however, were weaker in the C57BL/6 mice. Collectively, the differential transcriptome profiles of susceptible and resistant mouse strains with ECTV infection will be crucial for further uncovering the molecular mechanisms of the host-Orthopoxvirusinteraction.

scholarly journals Sex-Biased Expression of Pharmacogenes Across Human Tissues

Biomolecules ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1206
Author(s):  
Maria Laura Idda ◽  
Ilaria Campesi ◽  
Giovanni Fiorito ◽  
Andrea Vecchietti ◽  
Silvana Anna Maria Urru ◽  
...  
Keyword(s):  
Drug Response ◽  
Current Knowledge ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Tissue Expression ◽  
Systematic Investigation ◽  
Individual Response ◽  
Human Tissues ◽  
Expression Of Genes ◽  
Human Pharmacology

Individual response to drugs is highly variable and largely influenced by genetic variants and gene-expression profiles. In addition, it has been shown that response to drugs is strongly sex-dependent, both in terms of efficacy and toxicity. To expand current knowledge on sex differences in the expression of genes relevant for drug response, we generated a catalogue of differentially expressed human transcripts encoded by 289 genes in 41 human tissues from 838 adult individuals of the Genotype-Tissue Expression project (GTEx, v8 release) and focused our analysis on relevant transcripts implicated in drug response. We detected significant sex-differentiated expression of 99 transcripts encoded by 59 genes in the tissues most relevant for human pharmacology (liver, lung, kidney, small intestine terminal ileum, skin not sun-exposed, and whole blood). Among them, as expected, we confirmed significant differences in the expression of transcripts encoded by the cytochromes in the liver, CYP2B6, CYP3A7, CYP3A5, and CYP1A1. Our systematic investigation on differences between male and female in the expression of drug response-related genes, reinforce the need to overcome the sex bias of clinical trials.

scholarly journals Dynamic Clustering of Gene Expression

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Lingling An ◽  
R. W. Doerge
Keyword(s):  
Gene Expression ◽  
Developmental Stages ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Optimal Number ◽  
Sequential Data ◽  
Dynamic Clustering ◽  
Biological Processes ◽  
Time Frequency ◽  
Expression Of Genes

It is well accepted that genes are simultaneously involved in multiple biological processes and that genes are coordinated over the duration of such events. Unfortunately, clustering methodologies that group genes for the purpose of novel gene discovery fail to acknowledge the dynamic nature of biological processes and provide static clusters, even when the expression of genes is assessed across time or developmental stages. By taking advantage of techniques and theories from time frequency analysis, periodic gene expression profiles are dynamically clustered based on the assumption that different spectral frequencies characterize different biological processes. A two-step cluster validation approach is proposed to statistically estimate both the optimal number of clusters and to distinguish significant clusters from noise. The resulting clusters reveal coordinated coexpressed genes. This novel dynamic clustering approach has broad applicability to a vast range of sequential data scenarios where the order of the series is of interest.

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