FIG. 2.
Heat shock response of chaperone genes. (A) Primer extension (Pgro, Phrc) and S1 nuclease (Pcbp) analyses of H. pylori RNA extracted from cells grown at 37°C (0 min) (lane 1) or upon temperature shift to 42°C (lanes 2 to 10). The time interval at which RNA was extracted is indicated, in minutes, above each lane. The products of RNA elongation or protection by S1 nuclease are marked on the rightmost side of the autoradiography by the names of the corresponding promoters: Pgro, Phrc, and Pcbp. (B) Pattern of RNA accumulation at the indicated promoters as obtained by PhosphorImager analysis quantifications of the radioactive bands shown in panel A. It is worth mentioning that primer extensions conducted on the cbpA mRNA gave unsatisfactory results. By contrast, S1 nuclease mapping turned out to function very well in mapping both the transcription start site and the regulation of transcription upon stress conditions.