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Journal of Virology, August 2008, p. 8224-8229, Vol. 82, No. 16
0022-538X/08/$08.00+0     doi:10.1128/JVI.02584-07
Copyright © 2008, American Society for Microbiology. All Rights Reserved.

Human Metapneumovirus Small Hydrophobic Protein Inhibits NF-{kappa}B Transcriptional Activity{triangledown}

Xiaoyong Bao,1 Deepthi Kolli,1 Tianshuang Liu,1 Yichu Shan,1 Roberto P. Garofalo,1,2,3 and Antonella Casola1,2,3*

Departments of Pediatrics,1 Microbiology and Immunology,2 Sealy Center for Vaccine Development, University of Texas Medical Branch, Galveston, 301 University Blvd., Galveston, Texas 775553

Received 4 December 2007/ Accepted 2 May 2008


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ABSTRACT
 
Human metapneumovirus, a leading cause of respiratory tract infections in infants, encodes a small hydrophobic (SH) protein of unknown function. In this study, we showed that infection of airway epithelial cells or mice with recombinant human metapneumovirus lacking SH expression (rhMPV-{Delta}SH) enhanced secretion of proinflammatory mediators, including interleukin 6 (IL-6) and IL-8, encoded by two NF-kB-dependent genes, compared to infection with wild-type rhMPV. RhMPV-{Delta}SH infection resulted in enhanced NF-kB-dependent gene transcription and in increased levels of phosphorylated and acetylated NF-kB without affecting its nuclear translocation, identifying a possible novel mechanism by which paramyxovirus SH proteins modulate NF-kB activation.


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TEXT
 
Human metapneumovirus (hMPV) is a single-stranded, negative-sense RNA virus belonging to the Paramyxoviridae family and is the second most common cause of lower respiratory tract infections in children, the elderly, and immunocompromised patients (6, 16, 17, 22, 23, 31). The hMPV SH protein is a type II transmembrane glycoprotein (29), whose function is currently unknown. A recombinant hMPV virus lacking the SH protein is viable, grows as well as the wild-type virus, and is not significantly attenuated in animal models of infection (3, 5). The SH protein of mumps virus, parainfluenza virus 5 (PIV5), and respiratory syncytial virus (RSV), all members of the Paramyxoviridae family, has been shown to play a role in NF-{kappa}B activation, inhibiting tumor necrosis factor alpha (TNF-{alpha})-mediated signaling (18, 32). To determine whether the hMPV SH protein played a role in modulating cellular responses, we generated recombinant hMPV viruses, either wild type (rhMPV-WT) or one lacking SH (rhMPV-{Delta}SH), using the hMPV CAN83 strain as a template (4, 5). Recombinant virus generation was confirmed by restriction digestion analysis and viral genome sequencing, as previously described (4, 5). No mutations were found in either rhMPV-WT or -{Delta}SH compared to the naive virus. Recombinant viruses were passaged no more than four times in LLC-MK2 cells before use. To further verify SH gene deletion, G and SH gene expression was analyzed by reverse transcriptase PCR. As expected, there was no band corresponding to the SH gene in rhMPV-{Delta}SH, while the G gene, used as a positive control, was detected for both rhMPV-WT and rhMPV-{Delta}SH (Fig. 1A).


Figure 1
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  		FIG. 1. Characterization of recombinant viruses. (A) Verification of SH protein deletion. Viral RNA extracted from purified viruses was subjected to reverse transcriptase PCR using paired primers for the G or SH gene. PCR products were then analyzed on a 1% agarose gel. Numbers on the left represent molecular weight marker sizes, expressed in kilobases. (B) F-protein expression analysis in infected cells. A549 cells were infected with rhMPV-WT or rhMPV-{Delta}SH at a MOI of 2 and harvested to prepare total cell lysates at the indicated times (hours). Equal amounts of protein were subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis, followed by Western blotting using a monoclonal antibody against the hMPV F protein. Results are representative of three independent experiments. Densitometric analysis of band intensity was performed using the histogram function of Adobe Photoshop.

We next investigated viral replication of the recombinant viruses in comparison to the naive virus. Replication of naive hMPV, rhMPV-WT, and rhMPV-{Delta}SH in LLC-MK2 cells, analyzed by multicycle growth curves, was essentially the same (data not shown). To determine whether the initial replication of rhMPV-WT and rhMPV-{Delta}SH was similar in airway epithelial cells, A549 cells were infected with rhMPV-WT or -{Delta}SH at a multiplicity of infection (MOI) of 2, which resulted in 80 to 90% infected cells at 24 h postinfection (p.i.) as determined by immunofluorescence (data not shown). Viral titers at 6, 15, and 24 h p.i. were almost identical in A549 cells infected with rhMPV-WT or -{Delta}SH (data not shown). Similarly, accumulation of the F protein was not different at 3, 6, and 15 h p.i. between the two infections (Fig. 1B).

To determine whether the SH protein played a role in hMPV-induced gene expression, cytokine, chemokine, and type I interferon (IFN) production was assessed in the supernatants of A549 cells mock infected or infected with either rhMPV-{Delta}SH or rhMPV-WT at a MOI of 2 at various times p.i. The cytokine/chemokine concentration was quantified by using the Luminex-based Bio-Plex system (Bio-Rad Laboratories, Hercules, CA), while alpha and beta IFN concentrations were determined by enzyme-linked immunosorbent assays (PBL, Piscataway, NJ). We observed increased interleukin 6 (IL-6), IL-8, and MCP-1 production in cells infected with rhMPV-{Delta}SH, compared to results with rhMPV-WT, at 6 and 15 h p.i. (Fig. 2A), while there was not a significant difference in alpha/beta IFN secretion (data not shown). Amounts of IL-6, IL-8, and MCP-1 were no longer different at 24 h p.i. (data not shown).


Figure 2
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  		FIG. 2. Effect of SH-protein deletion on cytokine and chemokine secretion. (A) A549 cells were infected with rhMPV-WT or rhMPV-{Delta}SH at a MOI of 2 and harvested at 6, 15, and 24 h p.i. to measure secretion of cytokines, CXC chemokines, and CC chemokines in cell supernatants by using the Bio-Plex assay. Data shown are representative of three independent experiments. *, P < 0.05 relative to results for rhMPV-WT. (B) Female, six- to eight-week-old BALB/c mice were sham infected or infected intranasally with 1 x 106 PFU rhMPV-WT or -{Delta}SH. Bronchoalveolar lavage fluid was collected at days 1 and 2 p.i. Cytokine and chemokine concentrations were determined by Bio-Plex assay. Data represent the means for at least four animals per group and are representative of two independent experiments. *, P < 0.05 relative to results for rhMPV-WT.

To determine whether rhMPV-{Delta}SH infection would lead to enhanced cytokine/chemokine production in vivo, 6- to 8-week-old BALB/c mice were infected intranasally with 1 x 106 PFU of rhMPV-WT or -{Delta}SH or mock infected with culture medium, as previously described (20). Bronchoalveolar lavage fluid of mice infected with rhMPV-WT or -{Delta}SH was collected at days 1 and 2 p.i., when significant production of proinflammatory and antiviral molecules occurs in hMPV-infected BALB/c mice, as previously described (20). Infection with rhMPV-{Delta}SH resulted in a severalfold increase in TNF-{alpha} and IL-6 secretion at both days 1 and 2 p.i., while KC (mouse counterpart of human IL-8) and MCP-1 were increased only at day 1 or 2, respectively, compared to results for rhMPV-WT (Fig. 2B). There was no significant difference in viral replication between rhMPV-{Delta}SH and -WT at days 1 and 2 p.i. (1.26 x 104 ± 0.05 versus 2.01 x 104 ± 0.5 PFU/gram of lung tissue).

To investigate the role of SH in the regulation of IL-8 gene expression, the SH gene was cloned into EcoRI and XhoI restriction sites of the pCAGGS vector using the following primers: forward, 5'-ACGCgaattcATGATAACATTAGATGT-3'; reverse, 5'-TctcgagTCACGTAGAATCGAGACCGAGGAGAGGGTTAGGGATAGGCTTACCATCTATTGAGTGGTGATAGCACTTCCAC-3'. Underlining indicates the V5 tag, added to the C terminus of the SH protein. Lowercase indicates restriction sites. The expression pattern of cloned SH in 293 cells, detected by anti-V5 antibody, was similar to the SH expression pattern during naive hMPV infection (5) (Fig. 3A), where SH presents as unglycosylated protein, N-glycosylated protein, and a more extensively glycosylated form. We then compared IL-8 promoter activation in A549 cells infected with either rhMPV-WT or rhMPV-{Delta}SH in the presence or absence of SH protein expression provided in trans. Briefly, A549 cells were cotransfected with a reporter plasmid containing the luciferase gene under control of the IL-8 promoter and the SH expression plasmid or its empty vector, as previously described (11-13, 25). The next day, cells were mock infected or infected with rhMPV, rhMPV-WT, or rhMPV-{Delta}SH at a MOI of 2. At various times p.i., cells were lysed to independently measure luciferase and β-galactosidase (internal control for normalization) activity, as previously described (10). We found that there was significantly higher induction of IL-8 gene transcription at 3 and 6 h p.i. in cells infected with rhMPV-{Delta}SH than in those infected with rhMPV-WT (Fig. 3B), similar to what occurred for IL-8 protein secretion. A difference was no longer observed at 15 and 24 h p.i. (data not shown). Expression of the SH protein significantly reduced the rhMPV-{Delta}SH-induced increase in IL-8 promoter activation, confirming the ability of SH to inhibit virus-induced cellular gene transcription.


Figure 3
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  		FIG. 3. SH protein modulates NF-{kappa}B activation. (A) Western blot analysis of overexpressed SH protein. 293 cells were transfected with a plasmid expressing V5-tagged SH protein or its control vector using Fugene 6. At 30 h posttransfection, cells were lysed using radioimmunoprecipitation assay buffer and proteins were separated by 8% sodium dodecyl sulfate-polyacrylamide gel electrophoresis, followed by Western blotting using anti-V5 antibody. Different forms of expressed SH protein are indicated on the right, as follows: SH0, unglycosylated form of SH; SHg1 and SHg2, putative glycosylated forms 1 and 2. Molecular weight markers are indicated on the left. (B) SH deletion enhances hMPV-induced IL-8 gene transcription. A549 cells were transfected with a luciferase reporter plasmid containing the human IL-8 promoter either an SH-expressing plasmid or its empty vector (CV) and were infected with rhMPV-WT or -{Delta}SH at a MOI of 2. Cells were harvested at 3 and 6 h p.i. to measure luciferase activity. Uninfected plates served as controls. For each plate, luciferase was normalized to the β-galactosidase reporter activity. Data are representative of two independent experiments and are expressed as means ± standard deviations of normalized luciferase activity. (C) SH protein inhibits TNF-{alpha}-induced IL-8 gene transcription. 293 cells were cotransfected with 1 µg of a luciferase reporter plasmid containing the human IL-8 promoter and 1 µg of the plasmid expressing the SH protein or its control vector (CV). At 30 h posttransfection, cells were mock treated or treated with 5 µg/ml TNF-{alpha} for 6 h. Cells were then harvested to measure luciferase activity. CV- and SH-expressing cells without TNF-{alpha} stimulation served as controls. For each plate, luciferase was normalized to β-galactosidase reporter activity. Data are representative of two independent experiments and are expressed as n-fold induction of normalized luciferase activity. *, P < 0.05, relative to results for TNF-treated CV-transfected cells.

NF-kB activation is absolutely required for virus- and cytokine-induced IL-8 gene expression (7, 19). We then determined whether SH protein expression was able to inhibit cytokine-stimulated NF-{kappa}B-dependent gene transcription. 293 cells were transfected with the SH expression plasmid or its empty vector and the IL-8 promoter linked to the luciferase reporter gene. After transfection, cells were treated with 5 ng/ml of TNF-{alpha} for 6 h and harvested to measure luciferase activity. As shown in Fig. 3C, SH expression significantly inhibited TNF-induced IL-8 promoter activation, confirming a role of SH in NF-{kappa}B-dependent gene transcription.

NF-{kappa}B is a superfamily of ubiquitous transcription factors whose activation is controlled by accessory inhibitory proteins called I{kappa}Bs (2). NF-{kappa}B inducing stimuli cause I{kappa}B phosphorylation through activation of the I{kappa}B kinase (IKK) complex (24), with subsequent I{kappa}B proteolytic degradation (21), allowing NF-{kappa}B to enter the nucleus and activate gene transcription. We have previously shown that p65 and p50 are the two major NF-{kappa}B members induced by hMPV infection of airway epithelial cells (1, 19), with p65 being necessary for a variety of virus-induced chemokines and cytokine gene expression (28). To investigate the role of the SH protein in NF-{kappa}B activation, p65 nuclear translocation was compared with that of p50 in A549 cells infected with either rhMPV-WT or -{Delta}SH. Nuclear proteins, prepared as described previously (8), were used for Western blot analysis using antibody against p65 or p50 (Cell Signaling). We found that both viruses induced significant p65 and p50 nuclear translocation as early as 3 h p.i. Surprisingly, there was no difference in the nuclear abundance of either NF-{kappa}B subunit between rhMPV-WT- and rhMPV-{Delta}SH-infected cells (Fig. 4A). Similarly, hMPV-induced DNA binding to the IL-8 promoter NF-{kappa}B site was not affected by SH deletion (data not shown).


Figure 4
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  		FIG. 4. SH protein modulates NF-{kappa}B posttranslational modifications. (A) A549 cells were infected with rhMPV-WT or rhMPV-{Delta}SH at a MOI of 2 for various lengths of time and harvested to prepare nuclear extracts. Equal amounts of protein from uninfected and infected cells were analyzed by Western blotting using either an anti-p65 or anti-p50 antibody. Membranes were stripped and reprobed for lamin B as a control for equal loading of the samples. Results are representative of two independent experiments. (B) A549 cells were infected with rhMPV-WT or rhMPV-{Delta}SH at a MOI of 2 for various lengths of time and harvested by using sodium dodecyl sulfate sample buffer to prepare total cell lysates. Serine phosphorylation and lysine acetylation levels of p65 were analyzed by Western blotting using antibodies recognizing either anti-phospho-Ser276, anti-phospho-Ser536, or anti-acetylated Lys310. Membranes were stripped and reprobed for total p65 and β-actin as a control for equal loading of the samples. Results are representative of two independent experiments. (C) A549 cells were transfected with a plasmid encoding the SH protein or its control vector (CV). After 40 h, the cells were mock treated or treated with 5 µg/ml TNF-{alpha} for 6 h. Cells were then harvested by using sodium dodecyl sulfate sample buffer to prepare total cell lysates. Phosphorylation of p65 was detected by Western blotting using antibodies recognizing either anti-phospho-Ser276 or anti-phospho-Ser536. Membranes were stripped and reprobed for total p65 and β-actin as a control for equal loading of the samples. Densitometric analysis of band intensity of Ser276 and Ser536 p65 was performed using the histogram function of Adobe Photoshop. Results are shown after corrections to β-actin. Results are representative of two independent experiments.

NF-{kappa}B must undergo a variety of posttranslational modifications, including phosphorylation and acetylation, to achieve its full biological activity (14, 15). Inducible phosphorylation on distinct serine residues, including Ser276 and Ser536, has been shown to regulate NF-{kappa}B transcriptional activity without modification of nuclear translocation or DNA-binding affinity (33). Similarly, acetylation of specific lysine residues has been shown to modulate distinct NF-{kappa}B functions (14), with acetylation of lysine 310 (K310) enhancing p65-dependent gene transcription without affecting p65 nuclear translocation and DNA binding activity (15). To determine whether rhMPV-{Delta}SH infection led to enhanced p65 phosphorylation and/or acetylation, total cell lysates from rhMPV-WT- or rhMPV-{Delta}SH-infected A549 cells were prepared at different time points of infection. Levels of p65 Ser276 and Ser536 phosphorylation and K310 acetylation were analyzed by Western blotting using antibody against Ser276- or Ser536-phosphorylated p65 (Cell Signaling) or against K310-acetylated p65 (a gift from Warner C. Greene, University of California, San Francisco). RhMPV-WT infection induced significant Ser276 phosphorylation starting at 3 h p.i. and that of Ser536 at later time points (between 15 and 24 h p.i.) with no changes in K310 acetylation. On the other hand, rhMPV-{Delta}SH infection resulted in enhanced p65 Ser276 phosphorylation at all time points of infection, enhanced Ser536 phosphorylation at 15 and 24 h p.i., and increased K310 acetylation at early time points (3 and 6 h p.i.) (Fig. 4B) compared to results for rhMPV-WT. Compared to mock treatment, TNF-{alpha} treatment also significantly enhanced p65 phosphorylation, which was reversibly inhibited by SH overexpression (Fig. 4C), further confirming the inhibitory role of SH in p65 phosphorylation.

These results indicate that SH protein affects NF-{kappa}B-dependent gene transcription, likely by modulating NF-{kappa}B transcriptional activity and not by affecting nuclear translocation, and therefore the canonical pathway leading to NF-{kappa}B activation (24). Several kinases have been shown to be able to phosphorylate p65 on Ser276 or Ser536, including protein kinase A (PKA), casein kinase II, IKKβ, and IKK{varepsilon}/TBK1, following cellular stimulation with different stimuli (9, 26, 30). It is likely that hMPV SH inhibits one of these kinases, similar to what has been shown for the Rep78 protein of adeno-associated virus type II, which targets PKA activation (27). Our results indicate a possible novel mechanism by which paramyxovirus SH proteins can affect NF-{kappa}B activation in addition to inhibiting TNF-induced NF-{kappa}B nuclear translocation, as has been shown for the RSV and PIV5 SH proteins (18, 32). Whether the RSV and PIV5 SH proteins can also affect virus-induced NF-{kappa}B posttranslational modifications will require further investigation.

In summary, this study provides us with novel information on the potential role of the hMPV SH protein in regulating host immune responses. Further studies are needed to identify the precise mechanisms by which SH modulates hMPV-activated cell signaling.


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ACKNOWLEDGMENTS
 
This work was supported by grants NIEHS 06676 and NIAID P01 062885 and VRPRU grant N01 AI30039. X.B. was supported by NIAID training grant T32 AI07536.


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FOOTNOTES
 
* Corresponding author. Mailing address: Department of Pediatrics, Division of Child Health Research Center, 301 University Blvd., Galveston, TX 77555-0366. Phone: (409) 747-0581. Fax: (409) 772-1761. E-mail: ancasola{at}utmb.edu Back

{triangledown} Published ahead of print on 11 June 2008. Back


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REFERENCES
 
    1
  1. Bao, X., T. Liu, L. Spetch, D. Kolli, R. P. Garofalo, and A. Casola. 2007. Airway epithelial cell response to human metapneumovirus infection. Virology 368:91-101.[CrossRef][Medline]
    2. 2
  2. Beg, A. A., and A. S. J. Baldwin. 1993. The I kappa B proteins: multifunctional regulators of Rel/NF-kappa B transcription factors. Genes Dev. 7:2064-2070.[Free Full Text]
    3. 3
  3. Biacchesi, S., Q. N. Pham, M. H. Skiadopoulos, B. R. Murphy, P. L. Collins, and U. J. Buchholz. 2005. Infection of nonhuman primates with recombinant human metapneumovirus lacking the SH, G, or M2-2 protein categorizes each as a nonessential accessory protein and identifies vaccine candidates. J. Virol. 79:12608-12613.[Abstract/Free Full Text]
    4. 4
  4. Biacchesi, S., M. H. Skiadopoulos, K. C. Tran, B. R. Murphy, P. L. Collins, and U. J. Buchholz. 2004. Recovery of human metapneumovirus from cDNA: optimization of growth in vitro and expression of additional genes. Virology 321:247-259.[CrossRef][Medline]
    5. 5
  5. Biacchesi, S., M. H. Skiadopoulos, L. Yang, E. W. Lamirande, K. C. Tran, B. R. Murphy, P. L. Collins, and U. J. Buchholz. 2004. Recombinant human metapneumovirus lacking the small hydrophobic SH and/or attachment G glycoprotein: deletion of G yields a promising vaccine candidate. J. Virol. 78:12877-12887.[Abstract/Free Full Text]
    6. 6
  6. Boivin, G., Y. Abed, G. Pelletier, L. Ruel, D. Moisan, S. Cote, T. C. Peret, D. D. Erdman, and L. J. Anderson. 2002. Virological features and clinical manifestations associated with human metapneumovirus: a new paramyxovirus responsible for acute respiratory-tract infections in all age groups. J. Infect. Dis. 186:1330-1334.[CrossRef][Medline]
    7. 7
  7. Brasier, A. R., M. Jamaluddin, A. Casola, W. Duan, Q. Shen, and R. P. Garofalo. 1998. A promoter recruitment mechanism for tumor necrosis factor-alpha-induced interleukin-8 transcription in type II pulmonary epithelial cells. Dependence on nuclear abundance of Rel A, NF-kappaB1, and c-Rel transcription factors. J. Biol. Chem. 273:3551-3561.[Abstract/Free Full Text]
    8. 8
  8. Brasier, A. R., H. Spratt, Z. Wu, I. Boldogh, Y. Zhang, R. P. Garofalo, A. Casola, J. Pashmi, A. Haag, B. Luxon, and A. Kurosky. 2004. Nuclear heat shock response and novel nuclear domain 10 reorganization in respiratory syncytial virus-infected A549 cells identified by high-resolution two-dimensional gel electrophoresis. J. Virol. 78:11461-11476.[Abstract/Free Full Text]
    9. 9
  9. Buss, H., A. Dorrie, M. L. Schmitz, E. Hoffmann, K. Resch, and M. Kracht. 2004. Constitutive and interleukin-1-inducible phosphorylation of p65 NF-{kappa}B at serine 536 is mediated by multiple protein kinases including I{kappa}B kinase (IKK)-{alpha}, IKKβ, IKK{varepsilon}, TRAF family member-associated (TANK)-binding kinase 1 (TBK1), and an unknown kinase and couples p65 to TATA-binding protein-associated factor II31-mediated interleukin-8 transcription. J. Biol. Chem. 279:55633-55643.[Abstract/Free Full Text]
    10. 10
  10. Casola, A., N. Burger, T. Liu, M. Jamaluddin, A. R. Brasier, and R. P. Garofalo. 2001. Oxidant tone regulates RANTES gene transcription in airway epithelial cells infected with respiratory syncytial virus: role in viral-induced interferon regulatory factor activation. J. Biol. Chem. 276:19715-19722.[Abstract/Free Full Text]
    11. 11
  11. Casola, A., R. P. Garofalo, H. Haeberle, T. F. Elliott, A. Lin, M. Jamaluddin, and A. R. Brasier. 2001. Multiple cis regulatory elements control RANTES promoter activity in alveolar epithelial cells infected with respiratory syncytial virus. J. Virol. 75:6428-6439.[Abstract/Free Full Text]
    12. 12
  12. Casola, A., R. P. Garofalo, M. Jamaluddin, S. Vlahopoulos, and A. R. Brasier. 2000. Requirement of a novel upstream response element in respiratory syncytial virus-induced IL-8 gene expression. J. Immunol. 164:5944-5951.[Abstract/Free Full Text]
    13. 13
  13. Casola, A., A. Henderson, T. Liu, R. P. Garofalo, and A. R. Brasier. 2002. Regulation of RANTES promoter activation in alveolar epithelial cells after cytokine stimulation. Am. J. Physiol. Lung Cell Mol. Physiol. 283:L1280-L1290.[Abstract/Free Full Text]
    14. 14
  14. Chen, L. F., and W. C. Greene. 2004. Shaping the nuclear action of NF-{kappa}B. Nat. Rev. Mol. Cell Biol. 5:392-401.[CrossRef][Medline]
    15. 15
  15. Chen, L. F., S. A. Williams, Y. Mu, H. Nakano, J. M. Duerr, L. Buckbinder, and W. C. Greene. 2005. NF-{kappa}B RelA phosphorylation regulates RelA acetylation. Mol. Cell. Biol. 25:7966-7975.[Abstract/Free Full Text]
    16. 16
  16. Crowe, J. E., Jr., and J. V. Williams. 2003. Immunology of viral respiratory tract infection in infancy. Paediatr. Respir. Rev. 4:112-119.[CrossRef][Medline]
    17. 17
  17. Falsey, A. R., D. Erdman, L. J. Anderson, and E. E. Walsh. 2003. Human metapneumovirus infections in young and elderly adults. J. Infect. Dis. 187:785-790.[CrossRef][Medline]
    18. 18
  18. Fuentes, S., K. C. Tran, P. Luthra, M. N. Teng, and B. He. 2007. Function of the respiratory syncytial virus small hydrophobic protein. J. Virol. 81:8361-8366.[Abstract/Free Full Text]
    19. 19
  19. Garofalo, R. P., M. Sabry, M. Jamaluddin, R. K. Yu, A. Casola, P. L. Ogra, and A. R. Brasier. 1996. Transcriptional activation of the interleukin-8 gene by respiratory syncytial virus infection in alveolar epithelial cells: nuclear translocation of the RelA transcription factor as a mechanism producing airway mucosal inflammation. J. Virol. 70:8773-8781.[Abstract]
    20. 20
  20. Guerrero-Plata, A., A. Casola, and R. P. Garofalo. 2005. Human metapneumovirus induces a profile of lung cytokines distinct from that of respiratory syncytial virus. J. Virol. 79:14992-14997.[Abstract/Free Full Text]
    21. 21
  21. Henkel, T., T. Machleidt, I. Alkalay, M. Kronke, Y. Ben-Neriah, and P. A. Baeuerle. 1993. Rapid proteolysis of I kappa B-alpha is necessary for activation of transcription factor NF-kappa B. Nature 365:182-185.[CrossRef][Medline]
    22. 22
  22. Kahn, J. S. 2003. Human metapneumovirus: a newly emerging respiratory pathogen. Curr. Opin. Infect. Dis. 16:255-258.[Medline]
    23. 23
  23. Kahn, J. S. 2006. Epidemiology of human metapneumovirus. Clin. Microbiol. Rev. 19:546-557.[Abstract/Free Full Text]
    24. 24
  24. Karin, M., and M. Delhase. 2000. The I kappa B kinase (IKK) and NF-kappa B: key elements of proinflammatory signalling. Semin. Immunol. 12:85-98.[CrossRef][Medline]
    25. 25
  25. Liu, P., M. Jamaluddin, K. Li, R. P. Garofalo, A. Casola, and A. R. Brasier. 2007. Retinoic acid-inducible gene I mediates early antiviral response and toll-like receptor 3 expression in respiratory syncytial virus-infected airway epithelial cells. J. Virol. 81:1401-1411.[Abstract/Free Full Text]
    26. 26
  26. Sakurai, H., H. Chiba, H. Miyoshi, T. Sugita, and W. Toriumi. 1999. I{kappa}B kinases phosphorylate NF-{kappa}B p65 subunit on serine 536 in the transactivation domain. J. Biol. Chem. 274:30353-30356.[Abstract/Free Full Text]
    27. 27
  27. Schmidt, M., J. A. Chiorini, S. Afione, and R. Kotin. 2002. Adeno-associated virus type 2 Rep78 inhibition of PKA and PRKX: fine mapping and analysis of mechanism. J. Virol. 76:1033-1042.[Abstract/Free Full Text]
    28. 28
  28. Tian, B., Y. Zhang, B. Luxon, R. P. Garofalo, A. Casola, M. Sinha, and A. R. Brasier. 2002. Identification of NF-kB-dependent gene networks in respiratory syncytial virus-infected cells. J. Virol. 76:6800-6814.[Abstract/Free Full Text]
    29. 29
  29. van den Hoogen, B. G., T. M. Bestebroer, A. D. Osterhaus, and R. A. Fouchier. 2002. Analysis of the genomic sequence of a human metapneumovirus. Virology 295:119-132.[CrossRef][Medline]
    30. 30
  30. Wang, D., S. D. Westerheide, J. L. Hanson, and A. S. Baldwin, Jr. 2000. Tumor necrosis factor alpha-induced phosphorylation of RelA/p65 on Ser529 is controlled by casein kinase II. J. Biol. Chem. 275:32592-32597.[Abstract/Free Full Text]
    31. 31
  31. Williams, J. V., C. K. Wang, C. F. Yang, S. J. Tollefson, F. S. House, J. M. Heck, M. Chu, J. B. Brown, L. D. Lintao, J. D. Quinto, D. Chu, R. R. Spaete, K. M. Edwards, P. F. Wright, and J. E. Crowe, Jr. 2006. The role of human metapneumovirus in upper respiratory tract infections in children: a 20-year experience. J. Infect. Dis. 193:387-395.[CrossRef][Medline]
    32. 32
  32. Wilson, R. L., S. M. Fuentes, P. Wang, E. C. Taddeo, A. Klatt, A. J. Henderson, and B. He. 2006. Function of small hydrophobic proteins of paramyxovirus. J. Virol. 80:1700-1709.[Abstract/Free Full Text]
    33. 33
  33. Zhong, H., R. E. Voll, and S. Ghosh. 1998. Phosphorylation of NF-kappa B p65 by PKA stimulates transcriptional activity by promoting a novel bivalent interaction with the coactivator CBP/p300. Mol. Cell 1:661-671.[CrossRef][Medline]

Journal of Virology, August 2008, p. 8224-8229, Vol. 82, No. 16
0022-538X/08/$08.00+0     doi:10.1128/JVI.02584-07
Copyright © 2008, American Society for Microbiology. All Rights Reserved.




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