FIG. 3.

Promoter assays. E. coli XL1-Blue transformed with the promoter probe vector pSD5B or the promoter construct pSD5V, either alone or in combination with the RepA expression vector pQERA, was assayed for the level of β-galactosidase activity under noninducing or inducing (+I) conditions. pSD5B alone (5B), pSD5V alone (5V), pSD5V plus pQERA (5V+RepA), and pSD5V plus pQERA induced by IPTG (5V+RepA+I) were tested. Activities are given in Miller units. Data are means for three different experiments. Error bars indicate standard errors.