TABLE 3.

Mapping the chiA promoter in V. cholerae 569B

Plasmid	Segment of pTDCC2 inserteda	Promoter activityb (mean ± SD)
pRS415		34.1 ± 0.5
pZ1	31–465	191.6 ± 17.4
pZ3	99–465	70.8 ± 1.2
pZ13	123–465	48.6 ± 1.6
pZ56	157–465	44.1 ± 2.6

^a Numbering of nucleotides is consistent with that used for the sequence of the insert of pTDCC2 in Fig. 2. 

^b Units of β-galactosidase activity, determined by the method of Miller and Mekalanos (36).