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Homologous recombination in Dictyostelium discoideum
Abstract
To exploit DNA-mediated transformation as a tool for studying the mechanisms controlling differential gene expression in Dictyostelium discoideum, it is necessary to know the fate of exogenous sequences. I examined the ability of unlinked nonreplicating plasmid molecules to undergo homologous recombination during cotransformation of Dictyostelium amoebae. The transformation vector B10S confers resistance to the antibiotic G418 and was always presented to amoebae as a closed circle. Cotransforming DNA, containing a slime mold cDNA and sequences homologous to the primary vector, was presented either as a closed circle or as a linear molecule after digestion with restriction endonucleases which cut within one of three distinct regions of the plasmid. Remarkably, homologous recombination occurred in every clone examined. Moreover, the products of recombination were identical in all instances, irrespective of the presence or position of linearized ends. The ends of the linear templates were not recombinogenic. Accurate repair of the introduced double-strand break occurred frequently during recombination. The repair could occur inter-molecularly or, more likely, intra-molecularly, i.e. by recircularization. Recombination was predominantly nonreciprocal, and the recombinant products were present in separate head-to-tail tandem arrays. A single mechanism is proposed that links nonreciprocal recombination to the formation of homogenous head-to-tail tandem arrays.
Subject Area
Genetics|Molecular biology
Recommended Citation
Katz, Kenneth Scott, "Homologous recombination in Dictyostelium discoideum" (1990). Doctoral Dissertations Available from Proquest. AAI9110162.
https://scholarworks.umass.edu/dissertations/AAI9110162