title: Expression of the Escherichia coli lacZ gene on a plasmid vector in a cyanobacterium.
abstract: A biphasic plasmid vector was used to introduce the Escherichia coli K-12 lac operon into the unicellular cyanobacterium Agmenellum quadruplicatum PR-6. The PR-6 transformants expressed beta-galactosidase at nearly as high a level as did Escherichia coli transformants. In order to accomplish this, it was necessary to obtain PR-6 mutants that could be transformed by plasmids with unmodified recognition sites for the endogenous PR-6 restriction endonuclease Aqu I. These mutants were generated by a variation of the ectopic mutagenesis techniques that have been used in other naturally transforming bacteria. The ability to assay the expression of lacZ in PR-6 paves the way for the construction of gene fusions with various PR-6 promoters and quantitation of their expression under specific in vivo conditions.
mesh_terms: D000458:Cyanobacteria / Q000235:genetics*; D004262:DNA Restriction Enzymes; D004926:Escherichia coli / Q000235:genetics*; D005822:Genetic Vectors; D007763:Lac Operon; D010957:Plasmids; D001616:beta-Galactosidase / Q000378:metabolism
chemical_list: D004262:DNA Restriction Enzymes; D001616:beta-Galactosidase