FIG 1.

Gene composition and organization of the ars1 and ars2 operons in Agrobacterium tumefaciens 5A in relation to the nearby aio operon and the pst/pho gene cluster. Black dumbbell lines indicate the approximate regions of DNA used to construct the different arsR-lacZ fusions. The gray dumbbell line indicates the part of the arsR3-lysR region in the ars2 operon examined in the RT-PCR experiments. The black line connecting phoU1 and “reg. protein” is not drawn to scale and does not depict actual distance but illustrates the physical connectivity of the genes. The open reading frame denoted by a boldly outlined arrow represents a modification from prior depictions of the arsR1 locus. (Modified from reference 20.)