Nucleic Acids Research, 2001, Vol. 29, No. 2 e5
© 2001 Oxford University Press
Inducible expression of exogenous genes in Dictyostelium discoideum using the ribonucleotide reductase promoter
1Department of Chemistry and Biochemistry, 2Centre for Structural and Functional Genomics and 3Department of Biology, Concordia University, 1455 de Maisonneuve Boulevard West, Montreal, Quebec H3G 1M8, Canada and 4Zoologisches Institut, Ludwig-Maximilians-Universität, Luisenstrasse 14, D-80333 München, Germany
We report here the development of a regulated gene expression system for Dictyostelium discoideum based on the DNA-damage inducibility of the rnrB gene. rnrB, which codes for the small subunit of the enzyme ribonucleotide reductase, responds to DNA-damaging agents at all stages of the D.discoideum life cycle. Doses that have little effect on development have previously been shown to increase the level of the rnrB transcript by up to 15-fold. Here we show that all elements necessary for DNA-damage induction are contained in a 450 bp promoter fragment. We used a fusion of the rnrB promoter with the gene encoding GFP to demonstrate an up to 10-fold induction at the RNA level, which appears in all aspects similar to induction of the endogenous rnrB transcript. Using a fusion with the lacZ gene we observed an up to 7-fold induction at the protein level. These results indicate that the rnrB promoter can be used to regulate the expression of specific genes in D.discoideum. This controllable gene expression system provides the following new characteristics: the induction is rapid, taking place in the order of minutes, and the promoter is responsive at all stages of the D.discoideum life cycle.
* To whom correspondence should be addressed at: Department of Biology, Concordia University, 1455 de Maisonneuve Boulevard West, Montreal, Quebec H3G 1M8, Canada. Tel: +1 514 848 3405; Fax: +1 514 848 4504; Email: tsang{at}vax2.concordia.ca