scholarly journals The Ubiquitin Ligase Ubr11 Is Essential for Oligopeptide Utilization in the Fission Yeast Schizosaccharomyces pombe

2012 ◽  
Vol 11 (3) ◽  
pp. 302-310 ◽  
Author(s):  
Kenji Kitamura ◽  
Mai Nakase ◽  
Hideki Tohda ◽  
Kaoru Takegawa
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Ubiquitin Ligase ◽  
Peptide Transporter ◽  
Mrna Levels ◽  
Content Type ◽  
Peptide Transporters ◽  
Naturally Occurring ◽  
Actual Mechanism ◽  
Transcriptional Corepressors

ABSTRACT Uptake of extracellular oligopeptides in yeast is mediated mainly by specific transporters of the peptide transporter (PTR) and oligopeptide transporter (OPT) families. Here, we investigated the role of potential peptide transporters in the yeast Schizosaccharomyces pombe . Utilization of naturally occurring dipeptides required only Ptr2/SPBC13A2.04c and none of the other 3 OPT proteins (Isp4, Pgt1, and Opt3), whereas only Isp4 was indispensable for tetrapeptide utilization. Both Ptr2 and Isp4 localized to the cell surface, but under rich nutrient conditions Isp4 localized in the Golgi apparatus through the function of the ubiquitin ligase Pub1. Furthermore, the ubiquitin ligase Ubr11 played a significant role in oligopeptide utilization. The mRNA levels of both the ptr2 and isp4 genes were significantly reduced in ubr11 Δ cells, and the dipeptide utilization defect in the ubr11 Δ mutant was rescued by the forced expression of Ptr2. Consistent with its role in transcriptional regulation of peptide transporter genes, the Ubr11 protein was accumulated in the nucleus. Unlike the situation in Saccharomyces cerevisiae , the oligopeptide utilization defect in the S. pombe ubr11 Δ mutant was not rescued by inactivation of the Tup11/12 transcriptional corepressors, suggesting that the requirement for the Ubr ubiquitin ligase in the upregulation of peptide transporter mRNA levels is conserved in both yeasts; however, the actual mechanism underlying the control appears to be different. We also found that the peptidomimetic proteasome inhibitor MG132 was still operative in a strain lacking all known PTR and OPT peptide transporters. Therefore, irrespective of its peptide-like structure, MG132 is carried into cells independently of the representative peptide transporters.

scholarly journals Protective Role of Naturally Occurring Interleukin-17A-Producing γδ T Cells in the Lung at the Early Stage of Systemic Candidiasis in Mice

2011 ◽  
Vol 79 (11) ◽  
pp. 4503-4510 ◽  
Author(s):  
Takashi Dejima ◽  
Kensuke Shibata ◽  
Hisakata Yamada ◽  
Hiromitsu Hara ◽  
Yoichiro Iwakura ◽  
...  
Keyword(s):  
T Cells ◽  
Early Stage ◽  
Γδ T Cells ◽  
Protective Role ◽  
Dependent Manner ◽  
Peripheral Tissues ◽  
Content Type ◽  
Naturally Occurring ◽  
Interleukin 17A

ABSTRACTInterleukin-17A (IL-17A)-producing γδ T cells differentiate in the fetal thymus and reside in the peripheral tissues, such as the lungs of naïve adult mice. We show here that naturally occurring γδ T cells play a protective role in the lung at a very early stage after systemic infection withCandida albicans.Selective depletion of neutrophils byin vivoadministration of anti-Ly6G monoclonal antibody (MAb) impaired fungal clearance more prominently in the lung than in the kidney 24 h after intravenous infection withC. albicans.Rapid and transient production of IL-23 was detected in the lung at 12 h, preceding IL-17A production and the influx of neutrophils, which reached a peak at 24 h after infection. IL-17A knockout (KO) mice showed reduced infiltration of neutrophils concurrently with impaired fungal clearance in the lung after infection. The major source of IL-17A was the γδ T cell population in the lung, and Cδ KO mice showed little IL-17A production and reduced neutrophil infiltration after infection. Early IL-23 production in a TLR2/MyD88-dependent manner and IL-23-triggered tyrosine kinase 2 (Tyk2) signaling were essential for IL-17A production by γδ T cells. Thus, our study demonstrated a novel role of naturally occurring IL-17A-producing γδ T cells in the first line of host defense againstC. albicansinfection.

scholarly journals Silencing the Honey Bee (Apis mellifera) Naked Cuticle Gene (nkd) Improves Host Immune Function and Reduces Nosema ceranae Infections

2016 ◽  
Vol 82 (22) ◽  
pp. 6779-6787 ◽  
Author(s):  
Wenfeng Li ◽  
Jay D. Evans ◽  
Qiang Huang ◽  
Cristina Rodríguez-García ◽  
Jie Liu ◽  
...  
Keyword(s):  
Apis Mellifera ◽  
Immune Function ◽  
Honey Bee ◽  
Honey Bees ◽  
Nosema Ceranae ◽  
Negative Regulator ◽  
Mrna Levels ◽  
Content Type ◽  
Bee Disease

ABSTRACTNosema ceranaeis a new and emerging microsporidian parasite of European honey bees,Apis mellifera, that has been implicated in colony losses worldwide. RNA interference (RNAi), a posttranscriptional gene silencing mechanism, has emerged as a potent and specific strategy for controlling infections of parasites and pathogens in honey bees. While previous studies have focused on the silencing of parasite/pathogen virulence factors, we explore here the possibility of silencing a host factor as a mechanism for reducing parasite load. Specifically, we used an RNAi strategy to reduce the expression of a honey bee gene,naked cuticle(nkd), which is a negative regulator of host immune function. Our studies found thatnkdmRNA levels in adult bees were upregulated byN. ceranaeinfection (and thus, the parasite may use this mechanism to suppress host immune function) and that ingestion of double-stranded RNA (dsRNA) specific tonkdefficiently silenced its expression. Furthermore, we found that RNAi-mediated knockdown ofnkdtranscripts inNosema-infected bees resulted in upregulation of the expression of several immune genes (Abaecin,Apidaecin,Defensin-1, andPGRP-S2), reduction ofNosemaspore loads, and extension of honey bee life span. The results of our studies clearly indicate that silencing the hostnkdgene can activate honey bee immune responses, suppress the reproduction ofN. ceranae, and improve the overall health of honey bees. This study represents a novel host-derived therapeutic for honey bee disease treatment that merits further exploration.IMPORTANCEGiven the critical role of honey bees in the pollination of agricultural crops, it is urgent to develop strategies to prevent the colony decline induced by the infection of parasites/pathogens. Targeting parasites and pathogens directly by RNAi has been proven to be useful for controlling infections in honey bees, but little is known about the disease impacts of RNAi silencing of host factors. Here, we demonstrate that knocking down the honey bee immune repressor-encodingnkdgene can suppress the reproduction ofN. ceranaeand improve the overall health of honey bees, which highlights the potential role of host-derived and RNAi-based therapeutics in controlling the infections in honey bees. The information obtained from this study will have positive implications for honey bee disease management practices.

scholarly journals Growth Arrest-Specific 6 Enhances the Suppressive Function of CD4+CD25+Regulatory T Cells Mainly through Axl Receptor

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Guang-ju Zhao ◽  
Jia-yi Zheng ◽  
Jia-lan Bian ◽  
Long-wang Chen ◽  
Ning Dong ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
T Cells ◽  
Regulatory T Cells ◽  
Growth Arrest ◽  
Mrna Levels ◽  
Suppressive Function ◽  
Naturally Occurring ◽  
Tam Receptors

Background.Growth arrest-specific (Gas) 6 is one of the endogenous ligands of TAM receptors (Tyro3, Axl, and Mertk), and its role as an immune modulator has been recently emphasized. Naturally occurring CD4+CD25+regulatory T cells (Tregs) are essential for the active suppression of autoimmunity. The present study was designed to investigate whether Tregs express TAM receptors and the potential role of Gas6-TAM signal in regulating the suppressive function of Tregs.Methods.The protein and mRNA levels of TAM receptors were determined by using Western blot, immunofluorescence, flow cytometry, and RT-PCR. Then, TAM receptors were silenced using targeted siRNA or blocked with specific antibody. The suppressive function of Tregs was assessed by using a CFSE-based T cell proliferation assay. Flow cytometry was used to determine the expression of Foxp3 and CTLA4 whereas cytokines secretion levels were measured by ELISA assay.Results.Tregs express both Axl and Mertk receptors. Gas6 increases the suppressive function of Tregs in vitro and in mice. Both Foxp3 and CTLA-4 expression on Tregs are enhanced after Gas6 stimulation. Gas6 enhances the suppressive activity of Tregs mainly through Axl receptor.Conclusion. Gas6 has a direct effect on the functions of CD4+CD25+Tregs mainly through its interaction with Axl receptor.

Ontogeny and effect of cortisol on vasopressin-1b receptor expression in anterior pituitaries of fetal sheep

2003 ◽  
Vol 284 (1) ◽  
pp. R51-R56 ◽  
Author(s):  
Sharla F. Young ◽  
Jennifer L. Smith ◽  
Jorge P. Figueroa ◽  
James C. Rose
Keyword(s):  
Receptor Expression ◽  
Late Gestation ◽  
Mrna Levels ◽  
Fetal Sheep ◽  
Fetal Plasma ◽  
Protein Levels ◽  
Receptor Mrna ◽  
Naturally Occurring ◽  
V1b Receptor

Corticotroph responsiveness to arginine vasopressin (AVP) increases during late gestation in fetal sheep. The mechanism of this increase in AVP responsiveness is currently unknown but could be related to an increase in vasopressin type 1b (V1b) receptor expression in the pituitary during development. To determine if there are ontogenic changes in V1b receptor expression that may help explain the changes in ACTH responses to AVP, we studied pituitaries from three groups of fetal sheep [100, 120, or 140 days gestational age (dGA)]. V1b receptor mRNA and protein significantly decreased by 140 dGA. Peak V1b mRNA levels were detected at 100 dGA, while peak V1b protein levels were detected at 120 dGA. The reduction in V1b receptor expression in late gestation may be due to the naturally occurring peripartum increase in fetal plasma cortisol because cortisol infusion at 122–130 dGA decreased V1b receptor mRNA. Thus there is a marked decrease in the expression of the V1b receptor in the pituitary during fetal development, leaving the role of the V1b receptor in increasing AVP responsiveness uncertain.

scholarly journals Role of Phosphate Transport System Component PstB1 in Phosphate Internalization by Nostoc punctiforme

2016 ◽  
Vol 82 (21) ◽  
pp. 6344-6356 ◽  
Author(s):  
L. Hudek ◽  
D. Premachandra ◽  
W. A. J. Webster ◽  
L. Bräu
Keyword(s):  
Transport System ◽  
Phosphate Uptake ◽  
Phosphate Transport ◽  
Mrna Levels ◽  
Nostoc Punctiforme ◽  
Content Type ◽  
Phosphate Accumulation ◽  
Phosphate Availability ◽  
In Cells

ABSTRACTIn bacteria, limited phosphate availability promotes the synthesis of active uptake systems, such as the Pst phosphate transport system. To understand the mechanisms that facilitate phosphate accumulation in the cyanobacteriumNostoc punctiforme, phosphate transport systems were identified, revealing a redundancy of Pst phosphate uptake systems that exists across three distinct operons. Four separate PstB system components were identified.pstB1was determined to be a suitable target for creating phenotypic mutations that could result in the accumulation of excessive levels of phosphate through its overexpression or in a reduction of the capacity to accumulate phosphate through its deletion. Using quantitative real-time PCR (qPCR), it was determined thatpstB1mRNA levels increased significantly over 64 h in cells cultured in 0 mM added phosphate and decreased significantly in cells exposed to high (12.8 mM) phosphate concentrations compared to the level in cells cultured under normal (0.8 mM) conditions. Possible compensation for the loss of PstB1 was observed whenpstB2,pstB3, andpstB4mRNA levels increased, particularly in cells starved of phosphate. The overexpression ofpstB1increased phosphate uptake byN. punctiformeand was shown to functionally complement the loss of PstB inE. coliPstB knockout (PstB−) mutants. The knockout ofpstB1inN. punctiformedid not have a significant effect on cellular phosphate accumulation or growth for the most part, which is attributed to the compensation for the loss of PstB1 by alterations in thepstB2,pstB3, andpstB4mRNA levels. This study provides novelin vivoevidence that PstB1 plays a functional role in phosphate uptake inN. punctiforme.IMPORTANCECyanobacteria have been evolving over 3.5 billion years and have become highly adept at growing under limiting nutrient levels. Phosphate is crucial for the survival and prosperity of all organisms. In bacteria, limited phosphate availability promotes the synthesis of active uptake systems. The Pst phosphate transport system is one such system, responsible for the internalization of phosphate when cells are in phosphate-limited environments. Our investigations reveal the presence of multiple Pst phosphate uptake systems that exist across three distinct operons inNostoc punctiformeand functionally characterize the role of the gene product PstB1 as being crucial for the maintenance of phosphate accumulation. We demonstrate that the genespstB2,pstB3, andpstB4show alterations in expression to compensate for the deletion ofpstB1. The overall outcomes of this work provide insights as to the complex transport mechanisms that exist in cyanobacteria likeN. punctiforme, allowing them to thrive in low-phosphate environments.

scholarly journals Deletion ofv-chiAfrom a Baculovirus Reduces Horizontal Transmission in the Field

2013 ◽  
Vol 79 (13) ◽  
pp. 4056-4064 ◽  
Author(s):  
Vincent D'Amico ◽  
James Slavicek ◽  
John D. Podgwaite ◽  
Ralph Webb ◽  
Roger Fuester ◽  
...  
Keyword(s):  
Cell Culture ◽  
Horizontal Transmission ◽  
Laboratory Data ◽  
Disease Outbreaks ◽  
Wild Type ◽  
Content Type ◽  
Transmission Process ◽  
Naturally Occurring ◽  
First Time

ABSTRACTNucleopolyhedroviruses (NPVs) can initiate devastating disease outbreaks in populations of defoliating Lepidoptera, a fact that has been exploited for the purposes of biological control of some pest insects. A key part of the horizontal transmission process of NPVs is the degradation of the larval integument by virus-coded proteins called chitinases, such as V-CHIA produced by thev-chiAgenes. We used recombinant and naturally occurring strains of theLymantria disparNPV (LdMNPV) to test horizontal transmission in the field, release of virus from dead larvae under laboratory conditions, and cell lysis and virus release in cell culture. In the field, strains of LdMNPV lacking functionalv-chiAgenes showed reduced horizontal transmission compared to wild-type or repaired strains. These findings were mirrored by a marked reduction in released virus in laboratory tests and cell culture when the same strains were used to infect larvae or cells. Thus, this study tests the pivotal role of liquefaction and thev-chiAgene in field transmission for the first time and uses complementary laboratory data to provide a likely explanation for our findings.

scholarly journals Regulation of Peroxisome Proliferator-Activated Receptors by E6-Associated Protein

PPAR Research ◽  
2008 ◽  
Vol 2008 ◽  
pp. 1-8 ◽  
Author(s):  
Lakshmi Gopinathan ◽  
Daniel B. Hannon ◽  
Russell W. Smith ◽  
Jeffrey M. Peters ◽  
John P. Vanden Heuvel
Keyword(s):  
Ubiquitin Ligase ◽  
Target Genes ◽  
Peroxisome Proliferator ◽  
Mrna Levels ◽  
Independent Manner ◽  
Coordinate Regulation ◽  
Protein Levels ◽  
Ubiquitin Ligase Activity ◽  
Peroxisome Proliferator Activated Receptors

Peroxisome proliferator-activated receptors (PPARs) are nuclear receptors (NRs) that regulate genes involved in lipid and glucose metabolism. PPAR activity is regulated by interactions with cofactors and of interest are cofactors with ubiquitin ligase activity. The E6-associated protein (E6-AP) is an E3 ubiquitin ligase that affects the activity of other NRs, although its effects on PPARs have not been examined. E6-AP inhibited the ligand-independent transcriptional activity of PPARαand PPARβ, with marginal effects on PPARγ, and decreased basal mRNA levels of PPARαtarget genes. Inhibition of PPARαactivity required the ubiquitin ligase function of E6-AP, but occurred in a proteasome-independent manner. PPARαinteracted with E6-AP, and in mice treated with PPARαagonist clofibrate, mRNA and protein levels of E6-AP were increased in wildtype, but not in PPARαnull mice, indicating a PPARα-dependent regulation. These studies suggest coordinate regulation of E6-AP and PPARα, and contribute to our understanding of the role of PPARs in cellular metabolism.

scholarly journals The Staphylococcus aureus Chaperone PrsA Is a New Auxiliary Factor of Oxacillin Resistance Affecting Penicillin-Binding Protein 2A

2015 ◽  
Vol 60 (3) ◽  
pp. 1656-1666 ◽  
Author(s):  
Ambre Jousselin ◽  
Caroline Manzano ◽  
Alexandra Biette ◽  
Patricia Reed ◽  
Mariana G. Pinho ◽  
...  
Keyword(s):  
Binding Protein ◽  
Mrna Levels ◽  
Penicillin Binding Protein ◽  
Content Type ◽  
Oxacillin Resistance ◽  
Protein Membrane ◽  
Membrane Bound ◽  
Additional Level ◽  
Auxiliary Factor

Expression of the methicillin-resistantS. aureus(MRSA) phenotype results from the expression of the extra penicillin-binding protein 2A (PBP2A), which is encoded bymecAand acquired horizontally on part of the SCCmeccassette. PBP2A can catalyzedd-transpeptidation of peptidoglycan (PG) because of its low affinity for β-lactam antibiotics and can functionally cooperate with the PBP2 transglycosylase in the biosynthesis of PG. Here, we focus upon the role of the membrane-bound PrsA foldase protein as a regulator of β-lactam resistance expression. Deletion ofprsAaltered oxacillin resistance in three different SCCmecbackgrounds and, more importantly, caused a decrease in PBP2A membrane amounts without affectingmecAmRNA levels. The N- and C-terminal domains of PrsA were found to be critical features for PBP2A protein membrane levels and oxacillin resistance. We propose that PrsA has a role in posttranscriptional maturation of PBP2A, possibly in the export and/or folding of newly synthesized PBP2A. This additional level of control in the expression of themecA-dependent MRSA phenotype constitutes an opportunity to expand the strategies to design anti-infective agents.

scholarly journals Application of a Broad-Range Resequencing Array for Detection of Pathogens in Desert Dust Samples from Kuwait and Iraq

2011 ◽  
Vol 77 (13) ◽  
pp. 4285-4292 ◽  
Author(s):  
Tomasz A. Leski ◽  
Anthony P. Malanoski ◽  
Michael J. Gregory ◽  
Baochuan Lin ◽  
David A. Stenger
Keyword(s):  
Coxiella Burnetii ◽  
Human Pathogens ◽  
Content Type ◽  
Airborne Dust ◽  
Multiplexed Pcr ◽  
Naturally Occurring ◽  
High Prevalence ◽  
Biowarfare Agent ◽  
Infectious Potential

ABSTRACTA significant percentage of the human population is exposed to high levels of naturally occurring airborne dusts. Although the link between airborne particulate inhalation and a variety of respiratory diseases has long been established, little is known about the pathogenic role of the microbial component of the dust. In this study, we applied highly multiplexed PCR and a high-density resequencing microarray (RPM-TEI version 1.0) to screen samples of fine topsoil particles and airborne dust collected in 19 locations in Iraq and Kuwait for the presence of a broad range of human pathogens. The results indicated the presence of potential human pathogens, includingMycobacterium,Brucella,Coxiella burnetii,Clostridium perfringens, andBacillus. The presence ofCoxiella burnetii, a highly infectious potential biowarfare agent, was confirmed and detected in additional samples by use of a more sensitive technique (real-time PCR), indicating a high prevalence of this organism in the analyzed samples. The detection of potentially viable pathogens in breathable dusts from arid regions of Iraq and Kuwait underscores the importance of further study of these environments.

scholarly journals The Oxygenase CAO-1 of Neurospora crassa Is a Resveratrol Cleavage Enzyme

2013 ◽  
Vol 12 (9) ◽  
pp. 1305-1314 ◽  
Author(s):  
Violeta Díaz-Sánchez ◽  
Alejandro F. Estrada ◽  
M. Carmen Limón ◽  
Salim Al-Babili ◽  
Javier Avalos
Keyword(s):  
Neurospora Crassa ◽  
Sequence Similarity ◽  
Hydroxyl Groups ◽  
Mrna Levels ◽  
Pronounced Increase ◽  
Content Type ◽  
Carotenoid Metabolism ◽  
Cleavage Enzyme ◽  
Β Carotene

ABSTRACT The genome of the ascomycete Neurospora crassa encodes CAO-1 and CAO-2, two members of the carotenoid cleavage oxygenase family that target double bonds in different substrates. Previous studies demonstrated the role of CAO-2 in cleaving the C 40 carotene torulene, a key step in the synthesis of the C 35 apocarotenoid pigment neurosporaxanthin. In this work, we investigated the activity of CAO-1, assuming that it may provide retinal, the chromophore of the NOP-1 rhodopsin, by cleaving β-carotene. For this purpose, we tested CAO-1 activity with carotenoid substrates that were, however, not converted. In contrast and consistent with its sequence similarity to family members that act on stilbenes, CAO-1 cleaved the interphenyl Cα-Cβ double bond of resveratrol and its derivative piceatannol. CAO-1 did not convert five other similar stilbenes, indicating a requirement for a minimal number of unmodified hydroxyl groups in the stilbene background. Confirming its biological function in converting stilbenes, adding resveratrol led to a pronounced increase in cao-1 mRNA levels, while light, a key regulator of carotenoid metabolism, did not alter them. Targeted Δ cao-1 mutants were not impaired by the presence of resveratrol, a phytoalexin active against different fungi, which did not significantly affect the growth and development of wild-type Neurospora . However, under partial sorbose toxicity, the Δ cao-1 colonies exhibited faster radial growth than control strains in the presence of resveratrol, suggesting a moderate toxic effect of resveratrol cleavage products.

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