Rapid recombination among transfected plasmids, chimeric episome formation and trans gene expression in Plasmodium falciparum

Madhusudan Kadekoppala, Paul Cheresh, Drew Catron, Dar der Ji, Kirk Deitsch, Thomas E. Wellems, H. S. Seifert, Kasturi Haldar*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

30 Scopus citations

Abstract

Although recombination is known to be important to generating diversity in the human malaria parasite P. falciparum, the low efficiencies of transfection and the fact that integration of transfected DNA into chromosomes is observed only after long periods (typically 12 weeks or more) have made it difficult to genetically manipulate the blood stages of this major human pathogen. Here we show that co-transfection of a P. falciparum line with two plasmids, one expressing a green fluorescent protein (gfp) reporter and the other expressing a drug resistance marker (Tgdhfr-ts M23), allowed selection of a population in which about ∼30% of the parasites produce GFP. In these GFP-producing parasites, the transfected plasmids had recombined into chimeric episomes as large as 20 kb and could be maintained under drug pressure for at least 16 weeks. Our data suggest that chimera formation occurs early (detected by 7-14 days) and that it involves homologous recombination favored by presence of the same P. falciparum 5′hrp3 UTR promoting transcription from each plasmid. This indicates the presence of high levels of homologous recombination activity in blood stage parasites that can be used to drive rapid recombination of newly introduced DNA, study mechanisms of recombination, and introduce genes for trans expression in P. falciparum.

Original languageEnglish (US)
Pages (from-to)211-218
Number of pages8
JournalMolecular and Biochemical Parasitology
Volume112
Issue number2
DOIs
StatePublished - Mar 3 2001

Keywords

  • Co-transfection
  • GFP
  • Malaria
  • Recombination
  • Selectable marker
  • Transformation

ASJC Scopus subject areas

  • Parasitology
  • Molecular Biology

Fingerprint Dive into the research topics of 'Rapid recombination among transfected plasmids, chimeric episome formation and trans gene expression in Plasmodium falciparum'. Together they form a unique fingerprint.

Cite this