FIG. 1.

Procedures for isolation of a yibP disrupted mutant strain of E. coli (see Materials and Methods). rpsL*, an rpsL mutation conferring streptomycin resistance (the mutant allele is recessive to the wild-type rpsL⁺ gene). rep^ts, temperature-sensitive rep mutant gene that codes for the initiation protein of plasmid replication. Δori, deletion of the origin region of plasmid replication. bla, kan, and cat, ampicillin, kanamycin, and chloramphenicol resistance-conferring genes, respectively. B, BamHI; K, KpnI; A, Aor51HI.