FIG. 8.

Effect of orf1 and orf2 mutations on developmental lacZ expression under the control of the Ω4514 promoter. Developmental β-galactosidase specific activity from pTH10-3 containing the Ω4514 promoter region from −54 bp to +65 bp fused to lacZ and integrated at attB was measured as described previously (34) for at least three independent isolates of M. xanthus containing wild-type orf1 and orf2 (•), the orf1 mutation (○), or the orf2 mutation (▪). β-Galactosidase specific activity is expressed in nanomoles of o-nitrophenyl phosphate per minute per milligram of protein.