FIG. 3.

Primer extension analysis of purC and purD transcription start points. Primer extension experiments were performed with 10 μg of RNA extracted from CHCC285 with primer MKP57 (5′-CCAAACGCTTTTTATATACACAGA-3′). RNA was extracted from cells growing exponentially in SA medium (lane 2) or in the same medium supplemented by purines (lane 1). Lanes G, A, T, and C contain sequencing reaction mixtures using the same primer as in the primer extension experiments and PCR-generated template DNA. The nucleotide sequence of the region around the transcription start point is shown, with the starting nucleotide in boldface type. The picture was scanned at 300 dots per in. by using a Scan Jet 4c/T device (Hewlett-Packard) and the DeskScan II version 2.3 software. The TIF file was imported into Top Draw (version 3.1) for the addition of text.