Fig. 1

Proposed genetic organisation and regulation for the Rhizobium sp. RCI dehalogenase genes. R represents regulator gene that controls all three dehalogenases. P1 and P2 represent promoter regions of the structural genes, dehE, and dehD/dehL respectively. The arrows indicate sites of mutations. Original mutant lack the ability to express any of the three dehalogenase structural genes. Type 1 revertant regained the wild type ability to express all the three dehalogenase genes. Type 2 and 3 are constitutive for DehE and DehD/DehL respectively