Extension of the host range of Escherichia coli vectors by incorporation of RSF1010 replication and mobilization functions.

The broad-host-range vectors pSUP104, pSUP106, pSUP204, pSUP304, and pSUP404 are based on conventional Escherichia coli vectors (such as pBR325 and pACYC184) which have been modified to include the mobilization and broad-host-range replication functions of the IncQ plasmid RSF1010. These vector plasmids now can be maintained in a wide range of bacterial genera including Rhizobium, Agrobacterium, and Pseudomonas. They are efficiently mobilized by RP4 and thus are of particular interest for bacteria refractory to transformation. They offer the selection markers and cloning sites characteristic of the basic E. coli vectors. Therefore, they can be applied and adapted to a variety of cloning strategies. However, the cloning of very large fragments (e.g., in cosmid hybrids of pSUP106) was found to affect the stability of the recombinant molecules in a Rec+ background. This instability was not observed with smaller inserts of about 5 kilobases.