Molecular Genetics and Genomics

, Volume 270, Issue 3, pp 201–215

The gastrointestinal tract as the portal of entry for foreign macromolecules: fate of DNA and proteins

  • M. Palka-Santini
  • B. Schwarz-Herzke
  • M. Hösel
  • D. Renz
  • S. Auerochs
  • H. Brondke
  • W. Doerfler
Original Paper

DOI: 10.1007/s00438-003-0907-2

Cite this article as:
Palka-Santini, M., Schwarz-Herzke, B., Hösel, M. et al. Mol Genet Genomics (2003) 270: 201. doi:10.1007/s00438-003-0907-2

Abstract

The gastrointestinal tract (GIT) of mammals is the main portal of entry for foreign DNA and proteins. We have documented the fate of orally administered DNA or protein in the GIT of the mouse. The gene for the Green Fluorescent Protein (GFP) (4.7 kb) and the genomes of bacteriophage M13 (7.25 kb) and adenovirus type 2 (Ad2; 35.9 kb) were used as test DNAs. Persistence of these DNAs in the GIT was monitored by Southern hybridization and fluorescent in situ hybridization (FISH) or by PCR. For studies on proteins, recombinant glutathione-S-transferase was fed to mice. Survival of the protein in the GIT was then assessed by Western blotting. Depending on feeding schedules and food regimens, but irrespective of mouse strain or DNA length, fragments of the GFP gene or other DNAs were detectable for up to 18 h after feeding by Southern blot analysis. The GFP DNA could be visualized by FISH in cecal epithelia. A high fiber diet reduced the time required for food to pass through the GIT, and foreign DNA was cleared more rapidly. A high fat diet or complexing of the foreign DNA with protamine or lipofectin did not extend DNA persistence times. Undegraded GST protein was detected only in foregut contents up to 30 min after feeding. At 15 and 30 min post feeding, trace amounts of GST were found in extracts of the kidney. The GIT is constantly exposed to highly recombinogenic fragments of foreign DNA and to intact foreign proteins. Our data have implications for studies on carcinogenesis and mutagenesis, and on the pathogenicity of infectious proteins such as prions.

Keywords

Persistence of macromolecules in the gastrointestinal tractGreen Fluorescent Protein (GFP)Southern analysisUptake of foreign DNAGlutathionine-S-transferase

Copyright information

© Springer-Verlag 2003

Authors and Affiliations

  • M. Palka-Santini
    • 1
    • 3
  • B. Schwarz-Herzke
    • 1
    • 2
  • M. Hösel
    • 1
    • 2
  • D. Renz
    • 1
  • S. Auerochs
    • 1
    • 2
  • H. Brondke
    • 2
  • W. Doerfler
    • 1
    • 2
  1. 1.Institute of GeneticsUniversity of CologneCologneGermany
  2. 2.Institute of Clinical and Molecular VirologyUniversity of Erlangen-NürnbergErlangenGermany
  3. 3.Institute of Medical MicrobiologyUniversity of CologneCologneGermany