Key plasmids used in this study. pB264 is depicted as it occurs in Rhodococcus sp. B264-1. pAL298 is a binary plasmid that carries both pB264 (indicated in yellow) and a ColEI-origin of replication, as well as GntR (aacC1) and AmpR markers. The ColEI origin does not by itself support replication in Rhodococcus sp. strains B264-1 or I24 (not shown). pJANET, contains the bulk of pB264 in conjunction with a GntR marker and an origin of replication derived from pNG2 . Note that the pNG2 origin replicates well in both E. coli and Rhodococcus and that it functions well at both 30°C and 37°C. The relative positions and strandedness of each of the 9 ORFs within pB264 are indicated as heavy blue lines.