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Liang YC, Li R, Bao SR, Li ZL, Yin HZ, Dai CL. Artificial Downregulation of Ribosomal Protein L34 Restricts the Proliferation and Metastasis of Colorectal Cancer by Suppressing the JAK2/STAT3 Signaling Pathway. Hum Gene Ther 2023; 34:719-731. [PMID: 37427415 DOI: 10.1089/hum.2023.046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/11/2023] Open
Abstract
The highly conserved ribosomal protein L34 (RPL34) has been reported to play an essential role in the progression of diverse malignancies. RPL34 is aberrantly expressed in multiple cancers, although its significant in colorectal cancer (CRC) is currently unclear. Here, we demonstrated that RPL34 expression was higher in CRC tissues than in normal tissues. Upon RPL34 overexpression, the ability of proliferation, migration, invasion, and metastasis of CRC cells were significantly enhanced in vitro and in vivo. Furthermore, high expression of RPL34 accelerated cell cycle progression, activated the JAK2/STAT3 signaling pathway, and induced the epithelial-to-mesenchymal transition (EMT) program. Conversely, RPL34 silencing inhibited the CRC malignant progression. Utilizing immunoprecipitation assays, we identified the RPL34 interactor, the cullin-associated NEDD8-dissociated protein 1 (CAND1), which is a negative regulator of cullin-RING ligases. CAND1 overexpression reduced the ubiquitin level of RPL34 and stabilized RPL34 protein. CAND1 silencing in CRC cells resulted in a decrease in the ability of proliferation, migration, and invasion. CAND1 overexpression promoted CRC malignant phenotypes and induced EMT, and RPL34 knockdown rescued CAND1-induced CRC progression. In summary, our study indicates that RPL34 acts as a mediator, is stabilized by CAND1, and promotes proliferation and metastasis, in part, through the activation of the JAK2/STAT3 signaling pathway and induction of EMT in CRC.
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Affiliation(s)
- Yi-Chao Liang
- Department of General Surgery, Shengjing Hospital of China Medical University, Shenyang, P.R. China
| | - Rui Li
- Department of General Surgery, Shengjing Hospital of China Medical University, Shenyang, P.R. China
| | - Shu-Rui Bao
- Department of General Surgery, Shengjing Hospital of China Medical University, Shenyang, P.R. China
| | - Zhi-Long Li
- Department of General Surgery, Shengjing Hospital of China Medical University, Shenyang, P.R. China
| | - Hong-Zhuan Yin
- Department of General Surgery, Shengjing Hospital of China Medical University, Shenyang, P.R. China
| | - Chao-Liu Dai
- Department of General Surgery, Shengjing Hospital of China Medical University, Shenyang, P.R. China
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Prediction of Streptococcus uberis clinical mastitis treatment success in dairy herds by means of mass spectrometry and machine-learning. Sci Rep 2021; 11:7736. [PMID: 33833319 PMCID: PMC8032699 DOI: 10.1038/s41598-021-87300-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 03/26/2021] [Indexed: 12/26/2022] Open
Abstract
Streptococcus uberis is one of the leading pathogens causing mastitis worldwide. Identification of S. uberis strains that fail to respond to treatment with antibiotics is essential for better decision making and treatment selection. We demonstrate that the combination of supervised machine learning and matrix-assisted laser desorption ionization/time of flight (MALDI-TOF) mass spectrometry can discriminate strains of S. uberis causing clinical mastitis that are likely to be responsive or unresponsive to treatment. Diagnostics prediction systems trained on 90 individuals from 26 different farms achieved up to 86.2% and 71.5% in terms of accuracy and Cohen’s kappa. The performance was further increased by adding metadata (parity, somatic cell count of previous lactation and count of positive mastitis cases) to encoded MALDI-TOF spectra, which increased accuracy and Cohen’s kappa to 92.2% and 84.1% respectively. A computational framework integrating protein–protein networks and structural protein information to the machine learning results unveiled the molecular determinants underlying the responsive and unresponsive phenotypes.
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3
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Regulation of arginine biosynthesis, catabolism and transport in Escherichia coli. Amino Acids 2019; 51:1103-1127. [DOI: 10.1007/s00726-019-02757-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Accepted: 06/27/2019] [Indexed: 11/26/2022]
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Silué N, Marcantonio E, Campbell-Valois FX. RNA-Seq analysis of the T3SA regulon in Shigella flexneri reveals two new chromosomal genes upregulated in the on-state. Methods 2019; 176:71-81. [PMID: 30905752 DOI: 10.1016/j.ymeth.2019.03.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 03/11/2019] [Accepted: 03/20/2019] [Indexed: 02/06/2023] Open
Abstract
Shigella spp. are enterobacteria that invade human colonic mucosal cells using their Type Three Secretion Apparatus (T3SA). Shigella spp. possess a large plasmid that encodes most of its virulence factors and has been the focus of seminal work that defined the T3SA regulon. Thus, a global assessment of the transcriptional response regulated by the T3SA has been lacking. Herein we used RNA-Seq to identify genes that are differentially expressed when the T3SA is active (on-state) versus inactive (off-state). The quality of the RNA-Seq dataset was validated by its correlation with a prior microarray study. Using novel insights about the expression of non-coding regions, bioinformatic tools and experimentations, we demonstrated the existence of six operons and evidence that ipaH2.5 is a pseudogene. In addition, 86 chromosomal genes were downregulated in the on-state including several non-coding transcripts corresponding to short antisense RNA embedded in the 16S and 23S RNA genes, and 40 coding transcripts, whose cognate proteins were highly connected at the genetic and biochemical levels. Finally, we identified two novel chromosomal genes dubbed gem1 and gem3, which were upregulated in the on-state similarly to genes belonging to the T3SA regulon. The latter findings were validated on biological triplicates by droplet digital PCR. To our knowledge gem1 and gem3 are the first chromosomal members of the T3SA regulon that have no homologs on the plasmid. Our approach provides a path to optimizing RNA-Seq studies in case of bacterial models that had previously been the subject of medium to large scale studies.
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Affiliation(s)
- Navoun Silué
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Endrei Marcantonio
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - F-X Campbell-Valois
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada; Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada.
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Highly expressed ribosomal protein L34 indicates poor prognosis in osteosarcoma and its knockdown suppresses osteosarcoma proliferation probably through translational control. Sci Rep 2016; 6:37690. [PMID: 27883047 PMCID: PMC5121591 DOI: 10.1038/srep37690] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 11/01/2016] [Indexed: 01/25/2023] Open
Abstract
Osteosarcoma has devastating health implications on children and adolescents. However, due to its low incidence and high tumor heterogeneity, it is hard to achieve any further improvements in therapy and overall survival. Ribosomal protein L34 (RPL34) has been increasingly recognized to promote the proliferation of malignant cells, but its role in osteosarcoma has not been investigated. In this study, real-time quantitative PCR (RT-qPCR) and immunohistochemistry revealed that RPL34 was highly expressed in osteosarcoma tissues when compared to adjacent tissues and normal bone tissues. Survival analysis showed that high expression of RPL34 predicted a poor prognosis for osteosarcoma patients. Knockdown of RPL34 in Saos-2 cells via lentivirus-mediated small interfering RNA (siRNA) significantly inhibited cell proliferation, induced cell apoptosis and G2/M phase arrest. Moreover, screening of transcription factors using University of California Santa Cruz (UCSC) Genome Browser, protein-protein interaction (PPI) network analysis, Gene Ontology (GO) and pathway enrichment analysis revealed that MYC participates in the transcriptional regulation of RPL34, which interacts with the subunits of eukaryotic translation initiation factor 3 (eIF3) and probably involves the translational control of growth-promoting proteins. Our findings suggest that RPL34 plays an important role in the proliferation of osteosarcoma cells.
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Over-expressed RPL34 promotes malignant proliferation of non-small cell lung cancer cells. Gene 2016; 576:421-8. [DOI: 10.1016/j.gene.2015.10.053] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 10/21/2015] [Indexed: 01/18/2023]
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Abstract
Early investigations on arginine biosynthesis brought to light basic features of metabolic regulation. The most significant advances of the last 10 to 15 years concern the arginine repressor, its structure and mode of action in both E. coli and Salmonella typhimurium, the sequence analysis of all arg structural genes in E. coli and Salmonella typhimurium, the resulting evolutionary inferences, and the dual regulation of the carAB operon. This review provides an overall picture of the pathways, their interconnections, the regulatory circuits involved, and the resulting interferences between arginine and polyamine biosynthesis. Carbamoylphosphate is a precursor common to arginine and the pyrimidines. In both Escherichia coli and Salmonella enterica serovar Typhimurium, it is produced by a single synthetase, carbamoylphosphate synthetase (CPSase), with glutamine as the physiological amino group donor. This situation contrasts with the existence of separate enzymes specific for arginine and pyrimidine biosynthesis in Bacillus subtilis and fungi. Polyamine biosynthesis has been particularly well studied in E. coli, and the cognate genes have been identified in the Salmonella genome as well, including those involved in transport functions. The review summarizes what is known about the enzymes involved in the arginine pathway of E. coli and S. enterica serovar Typhimurium; homologous genes were identified in both organisms, except argF (encoding a supplementary OTCase), which is lacking in Salmonella. Several examples of putative enzyme recruitment (homologous enzymes performing analogous functions) are also presented.
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Liu H, Liang S, Yang X, Ji Z, Zhao W, Ye X, Rui J. RNAi-mediated RPL34 knockdown suppresses the growth of human gastric cancer cells. Oncol Rep 2015; 34:2267-72. [PMID: 26323242 PMCID: PMC4583519 DOI: 10.3892/or.2015.4219] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 08/07/2015] [Indexed: 01/23/2023] Open
Abstract
An increasing body of evidence suggests that ribosomal proteins may have ribosome-independent functions and may be involved in various physiological and pathological processes. To examine the role of ribosomal protein L34 (RPL34) in cancer transformation, we assessed its expression in gastric cancer cell lines and found it highly expressed. We further used lentivirus-mediated small interfering RNAs (siRNAs) to knockdown RPL34 expression in the human gastric cancer cell line SGC-7901. RNA interference (RNAi)-mediated inhibition of RPL34 expression in SGC-7901 cells significantly suppressed cell proliferation, increased apoptosis and arrested cells in the S phase. The results of the present study suggest that RPL34 plays a critical role in cell proliferation, cell cycle distribution and apoptosis of human malignant gastric cells.
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Affiliation(s)
- Hui Liu
- Department of Oncology, Wannan Medical College, Wuhu, Anhui 241001, P.R. China
| | - Shaohua Liang
- Department of Oncology, Wannan Medical College, Wuhu, Anhui 241001, P.R. China
| | - Xi Yang
- Department of Oncology, Wannan Medical College, Wuhu, Anhui 241001, P.R. China
| | - Zhaoning Ji
- Department of Medical Oncology, Yijishan Hospital of Wannan Medical College, Wuhu, Anhui 241001, P.R. China
| | - Wenying Zhao
- Department of Medical Oncology, Yijishan Hospital of Wannan Medical College, Wuhu, Anhui 241001, P.R. China
| | - Xiaobing Ye
- Department of Medical Oncology, Yijishan Hospital of Wannan Medical College, Wuhu, Anhui 241001, P.R. China
| | - Jing Rui
- Department of Medical Oncology, Yijishan Hospital of Wannan Medical College, Wuhu, Anhui 241001, P.R. China
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Defect in the formation of 70S ribosomes caused by lack of ribosomal protein L34 can be suppressed by magnesium. J Bacteriol 2014; 196:3820-30. [PMID: 25182490 DOI: 10.1128/jb.01896-14] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
To elucidate the biological functions of the ribosomal protein L34, which is encoded by the rpmH gene, the rpmH deletion mutant of Bacillus subtilis and two suppressor mutants were characterized. Although the ΔrpmH mutant exhibited a severe slow-growth phenotype, additional mutations in the yhdP or mgtE gene restored the growth rate of the ΔrpmH strain. Either the disruption of yhdP, which is thought to be involved in the efflux of Mg(2+), or overexpression of mgtE, which plays a major role in the import of Mg(2+), could suppress defects in both the formation of the 70S ribosome and growth caused by the absence of L34. Interestingly, the Mg(2+) content was lower in the ΔrpmH cells than in the wild type, and the Mg(2+) content in the ΔrpmH cells was restored by either the disruption of yhdP or overexpression of mgtE. In vitro experiments on subunit association demonstrated that 50S subunits that lacked L34 could form 70S ribosomes only at a high concentration of Mg(2+). These results showed that L34 is required for efficient 70S ribosome formation and that L34 function can be restored partially by Mg(2+). In addition, the Mg(2+) content was consistently lower in mutants that contained significantly reduced amounts of the 70S ribosome, such as the ΔrplA (L1) and ΔrplW (L23) strains and mutant strains with a reduced number of copies of the rrn operon. Thus, the results indicated that the cellular Mg(2+) content is influenced by the amount of 70S ribosomes.
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Abstract
Despite the fact that ribosomal proteins are the constituents of an organelle that is present in every cell, they show a surprising level of regulation, and several of them have also been shown to have other extra-ribosomal functions, such in replication, transcription, splicing or even ageing. This review provides a comprehensive summary of these important aspects.
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Affiliation(s)
- Rital B Bhavsar
- Department of Biology, University of Dayton, OH 45469-2320, USA
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11
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Adourian A, Jennings E, Balasubramanian R, Hines WM, Damian D, Plasterer TN, Clish CB, Stroobant P, McBurney R, Verheij ER, Bobeldijk I, van der Greef J, Lindberg J, Kenne K, Andersson U, Hellmold H, Nilsson K, Salter H, Schuppe-Koistinen I. Correlation network analysis for data integration and biomarker selection. MOLECULAR BIOSYSTEMS 2008; 4:249-59. [PMID: 18437268 DOI: 10.1039/b708489g] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
High-throughput biomolecular profiling techniques such as transcriptomics, proteomics and metabolomics are increasingly being used in in vivo studies to recognize and characterize effects of xenobiotics on organs and systems. Of particular interest are biomarkers of treatment-related effects which are detectable in easily accessible biological fluids such as blood. A fundamental challenge in such biomarker studies is selecting among the plethora of biomolecular changes induced by a compound and revealed by molecular profiling, to identify biomarkers which are exclusively or predominantly due to specific processes. In this work we present a cross-compartment correlation network approach, involving no a priori supervision or design, to integrate proteomic, metabolomic and transcriptomic data for selecting circulating biomarkers. The case study we present is the identification of biomarkers of drug-induced hepatic toxicity effects in a rodent model. Biomolecular profiling of both blood plasma and liver tissue from Wistar Hannover rats administered a toxic compound yielded many hundreds of statistically significant molecular changes. We exploited drug-induced correlations between blood plasma analytes and liver tissue molecules across study animals in order to nominate selected plasma molecules as biomarkers of drug-induced hepatic alterations of lipid metabolism and urea cycle processes.
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Affiliation(s)
- Aram Adourian
- BG Medicine Inc., 610N Lincoln Street, Waltham, MA, USA.
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Palaiomylitou MA, Matis KA, Zouboulis AI, Kyriakidis DA. A kinetic model describing cell growth and production of highly active, recombinant ice nucleation protein in Escherichia coli. Biotechnol Bioeng 2002; 78:321-32. [PMID: 11920448 DOI: 10.1002/bit.10107] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
A structured kinetic model, which describes the production of the recombinant ice nucleation protein in different conditions, was applied. The model parameters were estimated based on the variation of the specific growth rate and the intracellular product concentration during cultivation. The equations employed relate the cellular plasmid content or plasmid copy number with the cloned-gene expression; these correlations were successfully tested on the experimental data. The optimal nutrient conditions for the growth of Escherichia coli expressing the inaZ gene of Pseudomonas syringae were determined for the production of active ice nucleation protein. The kinetics of the cultures expressing the inaZ gene were studied in a bioreactor at different growth temperatures and nutrient conditions.
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Affiliation(s)
- M A Palaiomylitou
- Laboratory of Biochemistry, Department of Chemistry, Aristotle University of Thessaloniki, Thessaloniki 54006, Greece
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13
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Abstract
Ribosomal proteins have the complex task of coordinating protein biosynthesis to maintain cell homeostasis and survival. Recent evidence suggests that a number of ribosomal proteins have secondary functions independent of their involvement in protein biosynthesis. A number of these proteins function as cell proliferation regulators and in some instances as inducers of cell death. Specifically, expression of human ribosomal protein L13a has been shown to induce apoptosis, presumably by arresting cell growth in the G2/M phase of the cell cycle. In addition, inhibition of expression of L13a induces apoptosis in target cells, suggesting that this protein is necessary for cell survival. Similar results have been obtained in the yeast Saccharomyces cerevisiae, where inactivation of the yeast homologues of L13a, rp22 and rp23, by homologous recombination results in severe growth retardation and death. In addition, a closely related ribosomal protein, L7, arrests cells in G1 and also induces apoptosis. Thus, it appears that a group of ribosomal proteins may function as cell cycle checkpoints and compose a new family of cell proliferation regulators.
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Affiliation(s)
- F W Chen
- Department of Human Genetics, Mount Sinai School of Medicine, New York, NY 10029, USA
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Moorthamer M, Chaudhuri B. Identification of ribosomal protein L34 as a novel Cdk5 inhibitor. Biochem Biophys Res Commun 1999; 255:631-8. [PMID: 10049762 DOI: 10.1006/bbrc.1999.0145] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The cell cycle is regulated by sequential activation, inactivation of cyclin dependent kinases (Cdk-s). Like all other Cdk-s, the catalytic subunit of Cdk5 is present in cycling cells. However, its highest concentration is found in differentiated neurons, and the only known protein that activates Cdk5 (i.e., p35) is expressed solely in the brain. Active Cdk5 is thought to be involved in the in vivo phosphorylation of the neurofilament proteins and tau which are hyperphosphorylated in neurodegenerative diseases. Recent reports suggest that Cdk5 may also contribute to cellular differentiation. Therefore, it would not be unusual to surmise that there exist specific proteins that regulate Cdk5 activity in cycling cells. In order to find if this was true, a cDNA library prepared from HeLa cells was screened using the yeast-two-hybrid system. The 60S ribosomal protein, L34, was identified as a Cdk5-interacting protein. Biochemical analyses reveal that L34 cannot activate Cdk5 but potently inhibits the p35-activated kinase. L34 also interacts with Cdk4 and, in parallel, inhibits the Cdk4/cyclin D1 activity. Interestingly, L34 does not interact with Cdk2 in the two-hybrid assay nor does it inhibit the Cdk2/cyclin A enzyme. The fact that a ribosomal protein inhibits Cdk5 and Cdk4 may suggest that these two kinases have a cellular role in translational regulation.
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Affiliation(s)
- M Moorthamer
- Oncology Research, Novartis Pharma AG, Basel, Switzerland
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Lium EK, Panagiotidis CA, Wen X, Silverstein SJ. The NH2 terminus of the herpes simplex virus type 1 regulatory protein ICP0 contains a promoter-specific transcription activation domain. J Virol 1998; 72:7785-95. [PMID: 9733814 PMCID: PMC110090 DOI: 10.1128/jvi.72.10.7785-7795.1998] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The transcriptional program of herpes simplex virus is regulated by the concerted action of three immediate-early (alpha) proteins, ICP4, ICP27, and ICP0. The experiments described in this study examine the role of the acidic amino terminus (amino acids 1 to 103) of ICP0 in gene activation. When tethered to a DNA binding domain, this sequence activates transcription in the yeast Saccharomyces cerevisiae. Deletion of these amino acids affects the ability of ICP0 to activate alpha-gene promoter reporters in transient expression assays, while it has little or no effect on a beta- and a gamma-gene reporter in the same assay. Viruses that express the deleted form of ICP0 (ICP0-NX) have a small-plaque phenotype on both Vero cells and the complementing cell line L7. Transient expression and immunofluorescence analyses demonstrate that ICP0-NX is a dominant negative form of ICP0. Immunoprecipitation of ICP0 from cells coinfected with viruses expressing ICP0-NX and ICP0 revealed that ICP0 oligomerizes in infected cells. These data, in conjunction with the finding that ICP0-N/X is dominant negative, provide both biochemical and genetic evidence that ICP0 functions as a multimer in infected cells.
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Affiliation(s)
- E K Lium
- Department of Microbiology and College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA
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16
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Lungu O, Panagiotidis CA, Annunziato PW, Gershon AA, Silverstein SJ. Aberrant intracellular localization of Varicella-Zoster virus regulatory proteins during latency. Proc Natl Acad Sci U S A 1998; 95:7080-5. [PMID: 9618542 PMCID: PMC22745 DOI: 10.1073/pnas.95.12.7080] [Citation(s) in RCA: 157] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Varicella-Zoster virus (VZV) is a herpesvirus that becomes latent in sensory neurons after primary infection (chickenpox) and subsequently may reactivate to cause zoster. The mechanism by which this virus maintains latency, and the factors involved, are poorly understood. Here we demonstrate, by immunohistochemical analysis of ganglia obtained at autopsy from seropositive patients without clinical symptoms of VZV infection that viral regulatory proteins are present in latently infected neurons. These proteins, which localize to the nucleus of cells during lytic infection, predominantly are detected in the cytoplasm of latently infected neurons. The restriction of regulatory proteins from the nucleus of latently infected neurons might interrupt the cascade of virus gene expression that leads to a productive infection. Our findings raise the possibility that VZV has developed a novel mechanism for maintenance of latency that contrasts with the transcriptional repression that is associated with latency of herpes simplex virus, the prototypic alpha herpesvirus.
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Affiliation(s)
- O Lungu
- Department of Microbiology, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA
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Lium EK, Silverstein S. Mutational analysis of the herpes simplex virus type 1 ICP0 C3HC4 zinc ring finger reveals a requirement for ICP0 in the expression of the essential alpha27 gene. J Virol 1997; 71:8602-14. [PMID: 9343218 PMCID: PMC192324 DOI: 10.1128/jvi.71.11.8602-8614.1997] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The herpes simplex virus type 1 (HSV-1) immediate-early (IE) protein ICP0 has been implicated in the regulation of viral gene expression and the reactivation of latent HSV-1. Evidence demonstrates that ICP0 is an activator of viral gene expression yet does not distinguish between a direct or indirect role in this process. To further our understanding of the function of ICP0 in the context of the virus life cycle, site-directed mutagenesis of the consensus C3HC4 zinc finger domain was performed, and the effects of these mutations on the growth and replication of HSV-1 were assessed. We demonstrate that alteration of any of the consensus C3HC4 cysteine or histidine residues within this domain abolishes ICP0-mediated transactivation, alters the intranuclear localization of ICP0, and significantly increases its stability. These mutations result in severe defects in the growth and DNA replication of recombinant herpesviruses and in their ability to initiate lytic infections at low multiplicities of infection. These viruses, at low multiplicities of infection, synthesize wild-type levels of the IE proteins ICP0 and ICP4 at early times postinfection yet exhibit significant decreases in the synthesis of the essential IE protein ICP27. These findings reveal a role for ICP0 in the expression of ICP27 and suggest that the multiplicity-dependent growth of alpha0 mutant viruses results partially from reduced levels of ICP27.
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Affiliation(s)
- E K Lium
- Integrated Program in Cellular, Molecular and Biophysical Studies, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA
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Panagiotidis CA, Lium EK, Silverstein SJ. Physical and functional interactions between herpes simplex virus immediate-early proteins ICP4 and ICP27. J Virol 1997; 71:1547-57. [PMID: 8995681 PMCID: PMC191212 DOI: 10.1128/jvi.71.2.1547-1557.1997] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The ordered expression of herpes simplex virus type 1 (HSV-1) genes, during the course of a productive infection, requires the action of the virus immediate-early regulatory proteins. Using a protein interaction assay, we demonstrate specific in vitro protein-protein interactions between ICP4 and ICP27, two immediate-early proteins of HSV-1 that are essential for virus replication. We map multiple points of contact between these proteins. Furthermore, by coimmunoprecipitation experiments, we demonstrate the following. (i) ICP4-ICP27 complexes are present in extracts from HSV-1 infected cells. (ii) ICP27 binds preferentially to less modified forms of ICP4, a protein that is extensively modified posttranslationally. We also demonstrate, by performing electrophoretic mobility shift assays and supershifts with monoclonal antibodies to ICP4 or ICP27, that both proteins are present in a DNA-protein complex with a noncanonical ICP4 binding site present in the HSV thymidine kinase (TK) gene. ICP4, in extracts from cells infected with ICP27-deficient viruses, is impaired in its ability to form complexes with the TK site but not with the canonical site from the alpha4 gene. However, ICP4 is able to form complexes with the TK probe, in the absence of ICP27, when overproduced in mammalian cells or expressed in bacteria. These data suggest that the inability of ICP4 from infected cell extracts to bind the TK probe in the absence of ICP27 does not reflect a requirement for the physical presence of ICP27 in the complex. Rather, they imply that ICP27 is likely to modulate the DNA binding activity of ICP4 by affecting its posttranslational modification status. Therefore, we propose that ICP27, in addition to its established role as a posttranscriptional regulator of virus gene expression, may also modulate transcription either through direct or indirect interactions with HSV regulatory regions, or through its ability to modulate the DNA binding activity of ICP4.
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Affiliation(s)
- C A Panagiotidis
- Department of Microbiology, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA
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Lium EK, Panagiotidis CA, Wen X, Silverstein S. Repression of the alpha0 gene by ICP4 during a productive herpes simplex virus infection. J Virol 1996; 70:3488-96. [PMID: 8648681 PMCID: PMC190222 DOI: 10.1128/jvi.70.6.3488-3496.1996] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
During a productive infection by herpes simplex virus type 1 (HSV-1), ICP4, the major regulatory protein encoded by the alpha4 gene, binds to its transcription initiation site and represses the accumulation of alpha4 RNA. Evidence suggests that the degree of repression by ICP4 is a function of the absolute distance of an ICP4 binding site 3' from a TATA box. However, repression of HSV-1 gene expression by ICP4 through binding sites located 5' of TATA boxes, as in the case of the alpha0 gene, has not been adequately addressed. To this end, recombinant alpha0 promoters with various arrays of ICP4 binding sites flanking the alpha0 TATA box were constructed and recombined into the HSV-1 genome. Our results demonstrate the following. (i) Destruction of the endogenous alphaO ICP4 binding site, located 5' of the TATA box, results in derepression of alpha0 protein and RNA accumulation in infected Vero cells. (ii) The degree of alpha0 derepression is equivalent to that reported for the alpha4 gene following destruction of the ICP4 binding site at the alpha4 mRNA cap site in HSV-1. (iii) Introduction of an ICP4 binding site at the alpha0 mRNA cap site represses the accumulation of alpha0 RNA greater than threefold relative to the wild type. (iv) Changes in the abundance of alpha0 protein and RNA in infected cells do not affect replication or growth of HSV-1 in tissue culture. Our findings are consistent with the conclusion that alpha0 transcription is repressed by ICP4. These results demonstrate that repression by ICP4 can occur through binding sites located 5' of virus gene TATA boxes in HSV-1. Thus, models addressing repression of HSV-1 gene expression by ICP4 should incorporate the role of binding sites located 5', as well as 3', of virus gene TATA boxes.
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Affiliation(s)
- E K Lium
- Department of Microbiology, College of Physicians and Surgeons, Columbia University, New York 10032, USA
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Kitten T, Willis DK. Suppression of a sensor kinase-dependent phenotype in Pseudomonas syringae by ribosomal proteins L35 and L20. J Bacteriol 1996; 178:1548-55. [PMID: 8626280 PMCID: PMC177837 DOI: 10.1128/jb.178.6.1548-1555.1996] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The lemA gene of Pseudomonas syringae pv. syringae encodes the sensor kinase of a bacterial two-component signal transduction system. Phenotypes that are lemA dependent in P. syringae include lesion formation on bean and production of extracellular protease and the antibiotic syringomycin. Recently, the gacA gene has been identified as encoding the response regulator of the lemA regulon. To identify additional components that interact with LemA, suppressors of a lemA mutation were sought. A locus was identified that, when present in multiple copies, restores extracellular protease production to a lemA insertion mutant of P. syringae pv. syringae. This locus was found to encode the P. syringae homologs of translation initiation factor IF3 and ribosomal proteins L20 and L35 of Escherichia coli and other bacteria. Deletion analysis and data from Western immunoblots with anti-IF3 antiserum suggest that protease restoration does not require IF3. Deletion of both the L35 and L20 genes resulted in loss of protease restoration, whereas disruption of either gene alone increased protease restoration. Our results suggest that overexpression of either L20 or L35 is sufficient for protease restoration. It is unclear how alteration of ribosomal protein expression compensates in this instance for loss of a transcriptional activator, but a regulatory role for L20 and L35 apart from their function in the ribosome may be indicated.
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Affiliation(s)
- T Kitten
- Department of Plant Pathology, University of Wisconsin-Madison 53706, USA
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