TEICHOIC ACIDS OF ACTINOMYCETES. STRUCTURE AND REGULATORY ROLE IN CELLS

1985 ◽  
pp. 451-458 ◽  
Author(s):  
I.B. Naumova ◽  
G.M. Streshinskaya ◽  
N.S. Agre ◽  
V.D. Kusnetsov
Keyword(s):  
Regulatory Role ◽  
Teichoic Acids ◽  
In Cells

Activation of the MKK3-p38-MK2-ZFP36 axis by coronavirus infection restricts the upregulation of AU-rich element-containing transcripts in proinflammatory response

2022 ◽  
Author(s):  
Shumin Li ◽  
Siying Liu ◽  
Rui Ai Chen ◽  
Mei Huang ◽  
To Sing Fung ◽  
...  
Keyword(s):  
Map Kinase ◽  
Proinflammatory Cytokines ◽  
Binding Protein ◽  
Regulatory Role ◽  
Proinflammatory Response ◽  
Cytokines And Chemokines ◽  
Coronavirus Infection ◽  
Anti Inflammatory ◽  
Coronavirus Infections ◽  
In Cells

Coronavirus infections induce the expression of multiple proinflammatory cytokines and chemokines. We have previously shown that in cells infected with gammacoronavirus infectious bronchitis virus (IBV), interleukin 6 (IL-6) and IL-8 were drastically upregulated, and the MAP kinase p38 and the integrated stress response pathways were implicated in this process. In this study, we report that coronavirus infection activates a negative regulatory loop that restricts the upregulation of a number of proinflammatory genes. As revealed by the initial transcriptomic and subsequent validation analyses, the anti-inflammatory adenine-uridine (AU)-rich element (ARE)-binding protein, Zinc finger protein 36 (ZFP36) and its related family members were upregulated in cells infected with IBV and three other coronaviruses, alphacoronaviruses porcine epidemic diarrhea virus (PEDV) and human coronavirus 229E (HCoV-229E), and betacoronavirus HCoV-OC43, respectively. Characterization of the functional roles of ZFP36 during IBV infection demonstrated that ZFP36 promoted the degradation of transcripts coding for IL-6, IL-8, dual-specificity phosphatase 1 (DUSP1), prostaglandin-endoperoxide synthase 2 (PTGS2) and TNF-α-induced protein 3 (TNFAIP3), through binding to AREs in these transcripts. Consistently, knockdown and inhibition of JNK and p38 kinase activities reduced the expression of ZFP36, as well as the expression of IL-6 and IL-8. On the contrary, overexpression of mitogen-activated protein kinase kinase 3 (MKK3) and MAPKAP kinase-2 (MK2), the upstream and downstream kinases of p38, respectively, increased the expression of ZFP36 and decreased the expression of IL-8. Taken together, this study reveals an important regulatory role of the MKK3-p38-MK2-ZFP36 axis in coronavirus infection-induced proinflammatory response. Importance Excessive and uncontrolled induction and release of proinflammatory cytokines and chemokines, the so-called cytokine release syndrome (CRS), would cause life-threatening complications and multiple organ failure in severe coronavirus infections, including severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS) and COVID-19. This study reveals that coronavirus infection also induces the expression of ZFP36, an anti-inflammatory ARE-binding protein, promoting the degradation of ARE-containing transcripts coding for IL-6 and IL-8 as well as a number of other proteins related to inflammatory response. Furthermore, the p38 MAP kinase, its upstream kinase MKK3 and downstream kinase MK2 were shown to play a regulatory role in upregulation of ZFP36 during coronavirus infection cycles. This MKK3-p38-MK2-ZFP36 axis would constitute a potential therapeutic target for severe coronavirus infections.

scholarly journals A partial reconstitution implicates DltD in catalyzing lipoteichoic acid d-alanylation

2018 ◽  
Vol 293 (46) ◽  
pp. 17985-17996 ◽  
Author(s):  
B. McKay Wood ◽  
John P. Santa Maria ◽  
Leigh M. Matano ◽  
Christopher R. Vickery ◽  
Suzanne Walker
Keyword(s):  
Lipoteichoic Acid ◽  
Synthetic Lethal Interaction ◽  
Synthetic Lethal ◽  
Teichoic Acids ◽  
Biochemical Assays ◽  
Mutant Strains ◽  
Reconstituted System ◽  
Catalytic Dyad ◽  
In Cells

Modifications to the Gram-positive bacterial cell wall play important roles in antibiotic resistance and pathogenesis, but the pathway for the d-alanylation of teichoic acids (DLT pathway), a ubiquitous modification, is poorly understood. The d-alanylation machinery includes two membrane proteins of unclear function, DltB and DltD, which are somehow involved in transfer of d-alanine from a carrier protein inside the cell to teichoic acids on the cell surface. Here, we probed the role of DltD in the human pathogen Staphylococcus aureus using both cell-based and biochemical assays. We first exploited a known synthetic lethal interaction to establish the essentiality of each gene in the DLT pathway for d-alanylation of lipoteichoic acid (LTA) and confirmed this by directly detecting radiolabeled d-Ala-LTA both in cells and in vesicles prepared from mutant strains of S. aureus. We developed a partial reconstitution of the pathway by using cell-derived vesicles containing DltB, but no other components of the d-alanylation pathway, and showed that d-alanylation of previously formed lipoteichoic acid in the DltB vesicles requires the presence of purified and reconstituted DltA, DltC, and DltD, but not of the LTA synthase LtaS. Finally, based on the activity of DltD mutants in cells and in our reconstituted system, we determined that Ser-70 and His-361 are essential for d-alanylation activity, and we propose that DltD uses a catalytic dyad to transfer d-alanine to LTA. In summary, we have developed a suite of assays for investigating the bacterial DLT pathway and uncovered a role for DltD in LTA d-alanylation.

scholarly journals Cytidine metabolism in photoreceptor cells of the rat.

1983 ◽  
Vol 97 (3) ◽  
pp. 824-831 ◽  
Author(s):  
S Y Schmidt
Keyword(s):  
Photoreceptor Cell ◽  
Actinomycin D ◽  
Cell Metabolism ◽  
Photoreceptor Cells ◽  
Regulatory Role ◽  
Inner Retina ◽  
Cytidine Diphosphate ◽  
Silver Grains ◽  
Isolated Rat ◽  
In Cells

During brief (30-min) incubations, isolated rat retinas accumulated [3H]cytidine, converted it to cytidine triphosphate (CTP), and incorporated it into RNA and cytidine diphosphate-diacylglyceride (CDG), a phospholipid precursor of phosphatidylinositol (Pl). Labeled CTP, RNA, and CDG contents were found to be two- to three-fold higher in photoreceptor cells than in cells of the inner retina. Autoradiograms showed that, within photoreceptor cells, silver grains representing RNA were concentrated over the nuclei in dark and light, while silver grains representing CDG were concentrated over the inner segments only after incubation in dark. The formation of labeled CTP and the synthesis of RNA were enhanced in light, while labeled CDG levels became reduced in light concurrent with an increase in the incorporation of labeled inositol into Pl. The 3H-labeled CDG content, however, was increased two- to fourfold in light in the presence of actinomycin D, and autoradiograms show a heavy concentration of silver grains over the inner segments of photoreceptor cells. These findings establish a role for cytidine nucleotides in photoreceptor cell metabolism and in light-dependent increases in RNA and Pl synthesis. Furthermore, the observations indicate that a competition may exist in light for cytidine or CTP and suggest that availability of cytidine for CDG synthesis may have a regulatory role in Pl metabolism within the photoreceptor cells.

scholarly journals Positive Regulation of IκB Kinase Signaling by Protein Serine/Threonine Phosphatase 2A

2005 ◽  
Vol 280 (43) ◽  
pp. 35974-35982 ◽  
Author(s):  
Arlene E. Kray ◽  
Robert S. Carter ◽  
Kevin N. Pennington ◽  
Rey J. Gomez ◽  
Laura E. Sanders ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Cellular Response ◽  
Kinase Activity ◽  
Nuclear Translocation ◽  
Regulatory Role ◽  
Regulatory Subunit ◽  
Iκb Kinase ◽  
Phosphatase 2A ◽  
In Cells

Transcription factor NF-κB plays a key regulatory role in the cellular response to pro-inflammatory cytokines such as tumor necrosis factor-α (TNF). In the absence of TNF, NF-κB is sequestered in the cytoplasm by inhibitory IκB proteins. Phosphorylation of IκBby the β-catalytic subunit of IKK, a multicomponent IκB kinase, targets the inhibitor for proteolytic destruction and facilitates nuclear translocation of NF-κB. This pathway is initiated by TNF-dependent phosphorylation of T loop serines in IKKβ, which greatly stimulates IκB kinase activity. Prior in vitro mixing experiments indicate that protein serine/threonine phosphatase 2A (PP2A) can dephosphorylate these T loop serines and inactivate IKK, suggesting a negative regulatory role for PP2A in IKK signaling. Here we provided several in vivo lines of evidence indicating that PP2A plays a positive rather than a negative role in the regulation of IKK. First, TNF-induced degradation of IκB is attenuated in cells treated with okadaic acid or fostriecin, two potent inhibitors of PP2A. Second, PP2A forms stable complexes with IKK in untransfected mammalian cells. This interaction is critically dependent on amino acid residues 121–179 of the IKKγ regulatory subunit. Third, deletion of the PP2A-binding site in IKKγ attenuates T loop phosphorylation and catalytic activation of IKKβ in cells treated with TNF. Taken together, these data provide strong evidence that the formation of IKK·PP2A complexes is required for the proper induction of IκB kinase activity in vivo.

Cytoplasmic Tubules in Cells Infected with Laryngotracheitis Virus

1969 ◽  
Vol 27 ◽  
pp. 376-377
Author(s):  
A. M. Watrach
Keyword(s):  
Tissue Culture ◽  
Small Proportion ◽  
Chicken Embryo ◽  
Culture Cells ◽  
Tissue Culture Cells ◽  
Morphologic Characteristics ◽  
Infectious Laryngotracheitis ◽  
Laryngotracheitis Virus ◽  
In Cells

During a study of the development of infectious laryngotracheitis (LT) virus in tissue culture cells, unusual tubular formations were found in the cytoplasm of a small proportion of the affected cells. It is the purpose of this report to describe the morphologic characteristics of the tubules and to discuss their possible association with the development of virus.The source and maintenance of the strain of LT virus have been described. Prior to this study, the virus was passed several times in chicken embryo kidney (CEK) tissue culture cells.

Effect of Some Metabolic Inhibitors on Vinblastine-Induced Ribosomal-Granular Material Complexes

1971 ◽  
Vol 29 ◽  
pp. 548-549
Author(s):  
Awtar Krishan ◽  
Dora Hsu
Keyword(s):  
Granular Material ◽  
Rna Synthesis ◽  
Culture Medium ◽  
Actinomycin D ◽  
Metabolic Inhibitors ◽  
Protein And Rna Synthesis ◽  
Apparent Reduction ◽  
Plant Alkaloids ◽  
In Cells

Cells exposed to antitumor plant alkaloids, vinblastine and vincristine sulfate have large proteinacious crystals and complexes of ribosomes, helical polyribosomes and electron-dense granular material (ribosomal complexes) in their cytoplasm, Binding of H3-colchicine by the in vivo crystals shows that they contain microtubular proteins. Association of ribosomal complexes with the crystals suggests that these structures may be interrelated.In the present study cultured human leukemic lymphoblasts (CCRF-CEM), were incubated with protein and RNA-synthesis inhibitors, p. fluorophenylalanine, puromycin, cycloheximide or actinomycin-D before the addition of crystal-inducing doses of vinblastine to the culture medium. None of these compounds could completely prevent the formation of the ribosomal complexes or the crystals. However, in cells pre-incubated with puromycin, cycloheximide, or actinomycin-D, a reduction in the number and size of the ribosomal complexes was seen. Large helical polyribosomes were absent in the ribosomal complexes of cells treated with puromycin, while in cells exposed to cycloheximide, there was an apparent reduction in the number of ribosomes associated with the ribosomal complexes (Fig. 2).

Detection of Nucleic Acids in Cells or Tissue Sections Using In situ Polymerase Chain Reaction (PCR)

1996 ◽  
Vol 54 ◽  
pp. 16-17
Author(s):  
J. R. Hully ◽  
K. R. Luehrsen ◽  
K. Aoyagi ◽  
C. Shoemaker ◽  
R. Abramson
Keyword(s):  
Nucleic Acids ◽  
Viral Infections ◽  
Anatomical Location ◽  
Rt Pcr ◽  
Reverse Transcription Pcr ◽  
Cellular Source ◽  
Gene Transcripts ◽  
Initial Description ◽  
In Cells

The development of PCR technology has greatly accelerated medical research at the genetic and molecular levels. Until recently, the inherent sensitivity of this technique has been limited to isolated preparations of nucleic acids which lack or at best have limited morphological information. With the obvious exception of cell lines, traditional PCR or reverse transcription-PCR (RT-PCR) cannot identify the cellular source of the amplified product. In contrast, in situ hybridization (ISH) by definition, defines the anatomical location of a gene and/or it’s product. However, this technique lacks the sensitivity of PCR and cannot routinely detect less than 10 to 20 copies per cell. Consequently, the localization of rare transcripts, latent viral infections, foreign or altered genes cannot be identified by this technique. In situ PCR or in situ RT-PCR is a combination of the two techniques, exploiting the sensitivity of PCR and the anatomical definition provided by ISH. Since it’s initial description considerable advances have been made in the application of in situ PCR, improvements in protocols, and the development of hardware dedicated to in situ PCR using conventional microscope slides. Our understanding of the importance of viral latency or viral burden in regards to HIV, HPV, and KSHV infections has benefited from this technique, enabling detection of single viral copies in cells or tissue otherwise thought to be normal. Clearly, this technique will be useful tool in pathobiology especially carcinogenesis, gene therapy and manipulations, the study of rare gene transcripts, and forensics.

Absence of temporal ordering of apoptotic features in heat-shock treated leukemia and lymphoma cell lines

1996 ◽  
Vol 54 ◽  
pp. 758-759
Author(s):  
D. W. Fairbain ◽  
M.D. Standing ◽  
K.L. O'Neill
Keyword(s):  
Heat Shock ◽  
Cell Lines ◽  
Chromatin Condensation ◽  
Membrane Integrity ◽  
Resistant Cell ◽  
Membrane Blebbing ◽  
Late Loss ◽  
Induced Apoptosis ◽  
Dying Cells ◽  
In Cells

Apoptosis is a genetically defined response to physiological stimuli that results in cellular suicide. Features common to apoptotic cells include chromatin condensation, oligonucleosomal DNA fragmentation, membrane blebbing, nuclear destruction, and late loss of ability to exclude vital dyes. These characteristics contrast markedly from pathological necrosis, in which membrane integrity loss is demonstrated early, and other features of apoptosis, which allow a non-inflammatory removal of dead and dying cells, are absent. Using heat shock-induced apoptosis as a model for examining stress response in cells, we undertook to categorize a variety of human leukemias and lymphomas with regard to their response to heat shock. We were also interested in determining whether a common temporal order was followed in cells dying by apoptosis. In addition, based on our previous results, we investigated whether increasing heat load resulted in increased apoptosis, with particular interest in relatively resistant cell lines, or whether the mode of death changed from apoptosis to necrosis.

Umatilla Virus Association with Fibrils and Tubules in Cultured Cells

1980 ◽  
Vol 38 ◽  
pp. 476-477
Author(s):  
Neil M. Foster ◽  
Ruth D. Breckon
Keyword(s):  
Bluetongue Virus ◽  
Linear Array ◽  
Cultured Cells ◽  
Intimate Association ◽  
Infected Cells ◽  
Dark Staining ◽  
In Cells

Macrotubules have been described1 in cells infected with Umatilla virus (UMAV), an orbivirus for which bluetongue virus (BTV) is the protype. Macrotubules, often in linear array, were observed in the cytoplasm and in intimate association with viroplasms of infected cells. Macrotubules had outside and inside diameters of 20 and 15 nm and many had dark-staining centers with diameters similar to the interiors of the tubules. UMAV was 60 nm and the RNA core was 30 nm in diameter. This report describes the association of UMAV with macrotubules and two types of microtubules.

Photo-tethered molecular beacons for superior light-induction

2021 ◽  
Author(s):  
Robin Klimek ◽  
Mantian Wang ◽  
Vivien R. McKenney ◽  
Erin M. Schuman ◽  
Alexander Heckel
Keyword(s):  
Molecular Beacons ◽  
Light Induction ◽  
In Cells

Photolabile circularization of molecular beacons via backbone phosphates leads to superior probes to study spatiotemporal aspects of RNA in cells.

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