FIG. 2.

Primer extension analysis of lacPH transcription. (A) Analysis of lacPH transcription in the S. xylosus wild type, C2a. Total RNA was prepared from S. xylosus wild-type cells grown in B medium containing no additional sugar (lane 1), 25 mM lactose (lane 2), or 25 mM each lactose and glucose (lane 3). Fifteen micrograms of RNA and a ³²P-labeled lacP-specific primer were used for the primer extension reactions. One-fourth of each reaction mixture was separated on a 5% polyacrylamide–urea gel, together with a sequencing reaction mixture obtained with the same primer. The autoradiograph and the sequence interpretation around the +1 site are shown. (B) Analysis of lacPH transcription in the S. xylosus ccpA mutant, TX154. Total RNA was prepared from S. xylosus cells grown in B medium containing no additional sugar (lane 1), 25 mM lactose (lane 2), or 25 mM each glucose and lactose (lane 3). Fifteen micrograms of RNA and a ³²P-labeled lacP-specific primer were used in the primer extension reactions. One-fourth of each reaction mixture was separated on a 5% polyacrylamide–urea gel. The autoradiograph of the gel is shown.