SUMMARY: The bialaphos resistance gene, , was used as a selectable marker to isolate the bialaphos production genes () from the genome. The gene was cloned on overlapping restriction fragments using pIJ680 and pIJ702 in the bialaphos-sensitive host, . Although the restriction endonuclease cleavage map of these fragments was not similar to the cluster of , the presence and location of and four other genes as well as a gene required for the transcriptional activation of the cluster () was demonstrated by heterologous cloning experiments using a series of previously characterized bialaphos-nonproducing mutants. Since recombination-deficient mutants of streptomycetes have not been isolated, restored function provided by cloned homologous DNA results from both recombination (marker rescue) and complementation . In contrast to our previously reported homologous cloning experiments where we were able to define the position of mutant alleles by recombination, in these heterologous cloning experiments we observed little if any recombination between plasmid-cloned genes and the chromosome. As a result, this approach allowed us to define the location and orientation of functional genes using a genetic complementation test. The organization of the clustered genes was indistinguishable from the corresponding mutant alleles. The fact that the transcriptional regulatory gene, , functioned in implied that some transcriptional regulatory signals may also be interchangeable. In these two species, which have considerable nucleotide sequence divergence, the complex biochemical and genetic organization of the bialaphos biosynthetic pathway is conserved.


Article metrics loading...

Loading full text...

Full text loading...


Most cited this month Most Cited RSS feed

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error