Products of RT-PCR are shown. Lanes 1 and 10 contain a 1-kb Plus DNA ladder (Invitrogen), and lanes 2 to 9 and 11 to 14 contain the products of the RT-PCR performed with template RNA isolated from the following strains and the primers shown in Fig. 1: lane 2, C7(β), primers A and c; lane 3, C7(β)dtxR-TnUP, primers A and c; lane 4, C7(β)dtxR-TnIN primers A and c; lane 5, C7(β)ΔdtxR, primers A and c; lane 6, C7(β), primers E and b; lane 7, C7(β)dtxR-TnIN, primers E and b; lane 8, C7(β)dtxR-TnUP, primers E and b; lane 9, C7(β)ΔdtxR, primers D and b; lane 11, C7(β), primers B and b; lane 12, C7(β), primers B and b with no reverse transcriptase added; lane 13, C7(β)ΔdtxR, primers B and b; lane 14, C7(β)ΔdtxR, primers B and b with no reverse transcriptase added.