'uidA-antibiotic-resistance cassettes for insertion mutagenesis, gene fusions and genetic constructions.

We have constructed a series of promoterprobe cassettes that provides powerful tools for insertion mutagenesis, transcription fusions and genetic constructions. These cassettes contain the Tn9 chloramphenicol (CmR) and the Tn903 kanamycin (KmR) resistance genes which are expressed in a large variety of microorganisms; these antibiotic-resistance markers were associated with the uidA promoterless gene. This beta-glucuronidase-encoding gene of Escherichia coli K-12 has been successfully used as reporter gene for various organisms including prokaryotes and eukaryotes. The resulting 'uidA-KmR and 'uidA-CmR cassettes (truncated at the ') can be excized with most of the commonly used restriction enzymes. Furthermore, they are borne by ApR or CmR plasmids which facilitate their utilization. These promoter-probe cassettes allow transcriptional signal localization and regulation studies.