FIG. 2.

Transcription of pspA. (A) Northern analysis. Lanes were loaded with 20 μg of RNA and probed with a pspA-specific DNA probe. Lane 1, Rx1; lane 2, WU2. (B) Primer extension analysis of WU2. Nucleotides are indicated above the lanes. The ladder reads 5′ to 3′ from bottom to top. The initiating nucleotide was confirmed by spiking the A sequencing reaction mixture with the primer extension reaction mixture. Lane P contained the primer extension product. (C) Nucleotide sequences of the WU2 and D39 pspA promoter regions. The transcription initiation site is indicated (+1). The D39 sequence contains two additional nucleotides in the spacer region between the −35 and −10 sequences. A gap was therefore introduced into the WU2 sequence for clarity of alignment.