A shortened adeno-associated virus expression cassette for CFTR gene transfer to cystic fibrosis airway epithelia

Proc Natl Acad Sci U S A. 2005 Feb 22;102(8):2952-7. doi: 10.1073/pnas.0409845102. Epub 2005 Feb 9.


Adeno-associated viruses (AAVs) such as AAV5 that transduce airway epithelia from the apical surface are attractive vectors for gene transfer in cystic fibrosis (CF). However, their utility in CF has been limited because packaging of the insert becomes inefficient when its length exceeds approximately 4,900-5,000 bp. To partially circumvent this size constraint, we previously developed a CF transmembrane conductance regulator (CFTR) transgene that deleted a portion of the R domain (CFTRDeltaR). In this study, we focused on shortening the other elements in the AAV expression cassette. We found that portions of the CMV immediate/early (CMVie) enhancer/promoter could be deleted without abolishing activity. We also tested various intervening sequences, poly(A) signals, and an intron to develop an expression cassette that meets the size restrictions imposed by AAV. We then packaged these shortened elements with the CFTRDeltaR transgene into AAV5 and applied them to the apical surface of differentiated CF airway epithelia. Two to 4 weeks later, the AAV5 vectors partially corrected the CF Cl(-) transport defect. These results demonstrate that a single AAV vector can complement the CF defect in differentiated airway epithelia and thereby further the development of effective CF gene transfer.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Cells, Cultured
  • Chlorides / metabolism
  • Cystic Fibrosis / therapy*
  • Cystic Fibrosis Transmembrane Conductance Regulator / genetics*
  • Dependovirus / genetics*
  • Enhancer Elements, Genetic
  • Epithelium / metabolism
  • Gene Transfer, Horizontal
  • Genetic Therapy*
  • Genetic Vectors / genetics
  • Humans
  • Introns
  • Ion Transport
  • Promoter Regions, Genetic
  • Trachea / metabolism*


  • CFTR protein, human
  • Chlorides
  • Cystic Fibrosis Transmembrane Conductance Regulator