FIG. 3.

Primer extension analysis of lacR transcription in the S. xylosus wild type, C2a. RNA was isolated from wild-type cells grown in B medium without additional sugar (lane 1), with lactose (lane 2), or with lactose and glucose (lane 3). Fifteen micrograms of RNA and a ³²P-labeled lacR-specific primer were used in the primer extension reactions. One-fourth of the reaction mixtures were separated on 5% polyacrylamide–urea gels next to a sequencing reaction mixture obtained with the same primer. The autoradiograph and the sequence interpretation around the +1 sites are shown.