FIG. 1.

(A) The coxBAC locus of A. variabilis strain ATCC 29413. The restriction sites in λE2 are CelII (C), DraI (D), Eco47III (E), EcoRI (Ec), HindIII (H), HpaI (Hp), KpnI (K), MunI (M), MamI (Ma), MluNI (Ml), NheI (N), PstI (P), ScaI (S), SspI (Ss), SalI (Sa), and VspI (V). The small vertical bar in the coxA gene represents the binding site for oligonucleotide C (see Materials and Methods). pSSTUV17 is the plasmid used for construction of the CSW1 mutant. bom, basis of mobility (10); oriV, origin of replication in E. coli, not active in Anabaena. The hairpin denotes the position of a putative cutting site for RNase III (see Discussion). (B) Sequence of the cox locus around the SspI site (Ss) close to the putative translational start of coxB containing the two tsp (see Fig. 5). The hatched hexamers show putative −10 and −35 regions for tsp1. Similar sequences for tsp2 could not be identified.