FIG. 4.

Spo0A(A257V)∼P stimulates the rate of transcription initiation at the spoIIG promoter. Transcription was initiated by adding RNAPσ^A to a reaction mixture containing a linear DNA fragment encoding the spoIIG operon promoter, the initiating nucleotides (ATP and GTP), and either Spo0A or Spo0A(A257V) (phosphorylated or unphosphorylated). At various times, aliquots were removed and added to heparin plus CTP and UTP. After the reactions were terminated, ³²P-labeled spoIIG transcripts were separated by electrophoresis through an 8% denaturing polyacrylamide gel and detected by exposure to a phosphor screen (A), and their levels were determined by PhosphorImager analysis (B). The symbols indicate the addition of Spo0A∼P (filled circles), Spo0A (filled triangles), Spo0A(A257V)∼P (open circles), and Spo0A(A257V) (open triangles). A representative phosphorimage is shown. The values reflect the average of three independent experiments. The error bars indicate standard deviations.