Requirement of a novel upstream response element in respiratory syncytial virus-induced IL-8 gene expression.
Respiratory syncytial virus (RSV) produces intense pulmonary inflammation, in part, through its ability to induce chemokine synthesis in infected airway epithelial cells. In this study, we compare mechanisms for induction of the CXC chemokine IL-8, in human type II alveolar (A549) cells by RSV infection and by stimulation with the cytokine TNF. Promoter deletion and mutagenesis experiments indicate that although the region from -99 to -54 nt is sufficient for TNF-induced IL-8 transcription, this region alone is not sufficient for RSV-induced IL-8 transcription. Instead, RSV requires participation of a previously unrecognized element, spanning from -162 to -132 nt, that we term the RSV response element (RSVRE), and a previously characterized element at -132 to -99 nt, containing an AP-1 binding site. RSV infection of A549 cells induces increased RSVRE- and AP-1-binding activities and increased synthesis of IFN regulatory factor-1 protein, which is present in the RSVRE-binding complex. These data confirm that the IL-8 gene enhancers are controlled in a stimulus-specific fashion and participation of distinct promoter elements is required to activate gene transcription. These observations are important for rational design of inhibitors of RSV-induced lung inflammation.
Casola
A
A
Departments of Pediatrics and Internal Medicine and Sealy Center for Molecular Sciences, University of Texas Medical Branch, Galveston, TX 77555, USA.
Garofalo
R P
RP
Jamaluddin
M
M
Vlahopoulos
S
S
Brasier
A R
AR
D020121:5' Untranslated Regions / Q000235:genetics / Q000276:immunology*; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D002460:Cell Line; D016207:Cytokines / Q000494:pharmacology; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation / Q000235:genetics / Q000276:immunology*; D006801:Humans; D050856:Interferon Regulatory Factor-1; D007371:Interferon-gamma / Q000502:physiology; D016209:Interleukin-8 / Q000096:biosynthesis / Q000235:genetics*; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics / Q000276:immunology; D012136:Respiratory Syncytial Viruses / Q000276:immunology*; D020218:Response Elements / Q000276:immunology*; D017384:Sequence Deletion; D018808:Transcription Factor AP-1 / Q000235:genetics / Q000378:metabolism; D015533:Transcriptional Activation / Q000235:genetics / Q000276:immunology
D020121:5' Untranslated Regions; D016207:Cytokines; D004268:DNA-Binding Proteins; C494257:IRF1 protein, human; D050856:Interferon Regulatory Factor-1; D016209:Interleukin-8; D009687:Nuclear Proteins; D010750:Phosphoproteins; D018808:Transcription Factor AP-1; D007371:Interferon-gamma