Analysis of BsaN box requirements for transcription activation by BsaN/BicA. The ability of BsaN/BicA to directly activate the expression of truncated promoters was examined by providing regulatory genes in trans and measuring β-galactosidase activities arising from the expression of transcriptional promoter-lacZ fusions in E. coli DH5α. The top sequence of each gene includes the intact promoter region; sequence 1 is deleted up to the BsaN box; sequence 2 also includes a 6 nucleotide deletion of the BsaN box. Effect of BsaN/BicA on the expression of A. PbicA-lacZ fusion, B. PvirA-lacZ fusion and C. Ps1518-lacZ fusion; Ps1518 denotes the promoter region of BPSS1518. Effect of BsaN/BicA on the expression of D. PbprD-lacZ fusion and E. PbopA-lacZ fusion.