Light producing reporter plasmids for Escherichia coli K-12 that can be integrated into the chromosome

Plasmid vectors using the Photorhabdus luminescenslux operon can be used for real time measurements of promoter activity. We have generated a series of lux vectors that have a conditional origin of replication, different selectable markers and the attP sequence from λ. Single copies of these plasmids can be integrated into the λ attachment site in the Escherichia coli chromosome. We constructed reporter derivatives and compared light production when the plasmids were present in multiple copies and in single copies. We also demonstrated that expression could be induced under the appropriate conditions.