Site-directed transposon integration in human cells

Nucleic Acids Res. 2007;35(7):e50. doi: 10.1093/nar/gkm089. Epub 2007 Mar 7.

Abstract

The Sleeping Beauty (SB) transposon is a promising gene transfer vector that integrates nonspecifically into host cell genomes. Herein, we attempt to direct transposon integration into predetermined DNA sites by coupling a site-specific DNA-binding domain (DBD) to the SB transposase. We engineered fusion proteins comprised of a hyperactive SB transposase (HSB5) joined via a variable-length linker to either end of the polydactyl zinc-finger protein E2C, which binds a unique sequence on human chromosome 17. Although DBD linkage to the C-terminus of SB abolished activity in a human cell transposition assay, the N-terminal addition of the E2C or Gal4 DBD did not. Molecular analyses indicated that these DBD-SB fusion proteins retained DNA-binding specificity for their respective substrate molecules and were capable of mediating bona fide transposition reactions. We also characterized transposon integrations in the presence of the E2C-SB fusion protein to determine its potential to target predefined DNA sites. Our results indicate that fusion protein-mediated tethering can effectively redirect transposon insertion site selection in human cells, but suggest that stable docking of integration complexes may also partially interfere with the cut-and-paste mechanism. These findings illustrate the feasibility of directed transposon integration and highlight potential means for future development.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Binding Sites
  • Catalysis
  • DNA Transposable Elements*
  • DNA-Binding Proteins / chemistry
  • Gene Transfer Techniques*
  • Genome, Human
  • HeLa Cells
  • Humans
  • Mutagenesis, Insertional*
  • Mutagenesis, Site-Directed*
  • Protein Engineering
  • Protein Structure, Tertiary
  • Recombinant Fusion Proteins / analysis
  • Recombinant Fusion Proteins / chemistry
  • Transposases / genetics*
  • Transposases / metabolism*

Substances

  • DNA Transposable Elements
  • DNA-Binding Proteins
  • Recombinant Fusion Proteins
  • Transposases
  • sleeping beauty transposase, human