Respiratory synctial virus (RSV), a common etiologic agent of epidemic pediatric wheezing, produces pulmonary inflammation by induces the transcriptional production of the CC chemokine, RANTES, by the airway epithelium. Although the nuclear factor of kappaB (NF-kappaB) response element is necessary for RANTES expression, two additional cis DNA control elements have been identified preliminary in its proximal promoter. In a eukaryotic cell expression assay, we demonstrate that selective expression of the RSV F glycoprotein activates RANTES promoter expression. In addition, RSV infection activates mitogen activated protein kinase (MAPK) kinase (MEK), a signaling molecule required for inducible RANTES secretion. In this project, we will pursue the hypothesis that RSV activates RANTES transcription through two separate cis DNA control elements. RSV activates RANTES secretion through expression of the F glycoprotein and activation of the MAPK cascade.
Our specific aims are to: 1) To define the mechanism for transcriptional activation of RANTES by RSV. The cis elements required for RANTES induction by RSV (Domains 1 and 2) will be defined functionally by transient transfection assays and regions of protein-DNA interaction will be identified by DNase I footprint analysis; 2) To determine the mechanism for RSV glycoprotein F in expression, we will identify the necessary domains necessary for RANTES production, and establish the relationship of F to MAPK activation; 3) To determine the mechanism of NF-kappaB activation of RANTES by RSV. RANTES is distinct from other NF-kappaB responsive genes in that RANTES is non- inducible without ankyrin repeat protect expression (such as IkappaBR). We have discovered the expression the an additional ankyrin repeat containing protein, BCL-3, not subunits binding to the RANTES and, separately, the highly inducible IL-8 gene promoter to the hypothesis that ankyrin repeat containing proteins are recruited to the RANTES NF- kappaB complex. These studies will identify control mechanisms required for RANTES induction in pulmonary infection and may allow for identification of targets that can be use to block eosinophil inflammation in viral-exacerbated asthma.
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