Deletion analysis of promoter regions of genes 14 and 19. β-galactosidase activity of extracts prepared from E. coli cultures of bacteria transformed with various deletion constructs was determined. Panels A and C have cartoons depicting deletion constructs and their orientations for genes 14 and 19, respectively. (Solid black boxes represent lacZ gene, and right and left arrowhead lines show orientation of the promoter regions ligated in front of the lacZ coding sequence. Lengths of the promoter regions in base pairs are indicated on the left. Panels B and D contain the β-galactosidase activity analysis data. (β-galactosidase activity was expressed as percent activity relative to the activity observed for full length promoter segments.) Data are presented with SD values calculated from four independent experiments (P ≤ 0.001).