FIG. 1.

An upstream DNA element negatively regulates Ω4406 expression. Developmental expression from the 1.0-kb (bp −533 to 485) (○) or 0.6-kb (bp −100 to 485) (▪) DNA segment containing the Ω4406 promoter fused to lacZ and integrated at the Mx8 phage attachment site in the chromosome of M. xanthus wild-type DK1622, was measured for three independently isolated transformants (see Materials and Methods). The graph shows the average β-galactosidase specific activity expressed in nanomoles of o-nitrophenyl phosphate per minute per milligram of protein, and error bars show 1 standard deviation of the data.