Fig. 4.

Developmental lacZ expression patterns of the WT nla6 and nla28 promoter fragments. Fragments of the nla6 (A) and nla28 (B) promoter regions were cloned into a promoterless lacZ expression vector and integrated into the Mx8 phage attachment site in the M. xanthus chromosome. Mean β-galactosidase–specific activities were determined at various times in development from six to nine replicates. The mean β-galactosidase–specific activities shown are relative to that found at 0 h (vegetative growth). The error bars indicate SDs of the mean.