Please fill the gaps using the words in the box above. 
   
  Transient transfection of epithelial cells with lipid reagents has been limited because of toxicity and 
    
    
     of efficacy. In this study, we show that more recently developed lipids transfect nonpolarized human airway epithelial 
      
      
       with high efficiency and little or no toxicity. Because of this success, we hypothesized that these lipids may also 
        
        
         transient transfection of polarized epithelial monolayers.
 
    A panel of reagents was tested for transfer of the reporter gene luciferase (LUC) 
      
      
       polarized monolayers of non-cystic fibrosis (non-CF) and CF human bronchial epithelial cells, MDCK epithelial cell monolayers, and, ultimately, primary non-CF and CF airway epithelial cells. 
      
    Lipid reagents, 
      
      
       were most successful in initial LUC assays, were also tested for transfer of vectors bearing the reporter gene green fluorescent protein (GFP) and for successful transfection and expression of an epithelial-specific protein (CFTR). Electrophysiological, biochemical, and immunological assays were 
        
        
         to show successful complementation of an epithelial monolayer with transiently expressed CFTR. We also present findings that help facilitate monolayer formation by these airway epithelial cell 
          
          
          . Together, these data show that polarized monolayers are transfected transiently with 
          
          
             recently developed lipids, specifically LipofectAMINE PLUS and LipofectAMINE 2000. Transient transfection of epithelial monolayers 
            
            
               a powerful system in which to express the cDNA of any epithelium-specific protein transiently in a native polarized epithelium to study protein 
              
              
                .