Construction and application of plasmid pZCY11 for analyzing gene functions and expressions in Myxococcus

OBJECTIVE: To construct a plasmid for analyzing gene functions and expressions and to study the MXAN1334 gene in Myxococcus xanthus with the plasmid. METHODS: We constructed the plasmid vector pZCY11, amplified MXAN1334 gene fragment from M. xanthus DK1622 by PCR, and inserted the fragment into a site upstream of lacZ, resulting in the recombinant plasmid pZCY13. The plasmid pZCY13 was transformed by electroporation to DK1622, producing a mutant ZC16-18 (deltaMXAN1334). RESULTS: The plasmid pZCY11 carried the resistance gene aph as the selectable marker, the replication origin of OriR6K and promoterless reporter gene lacZ. We examined the swarm expansions of ZC16-18 on CTT hard and soft agar, and the result indicated that MXAN1334 gene was probably involved in gliding motility in M. xanthus. In addition, beta-galactosidase activity of ZC16-18 was detected by X-gal assay and the blue color developed was used to mark the colony growth. Time of colour showed that MXAN1334 gene was expressed in the early stage in M. xanthus. CONCLUSION: The plasmid vector pZCY11 made it more convenient for the study on functions and the expressions of target gene in M. xanthus.