FIG. 5.

Primer extension analysis of gudB mRNA. Primer oBB60 was extended with reverse transcriptase by using total RNA from B. subtilis SMY grown in glucose minimal medium containing ammonia or proline as nitrogen source or from Saccharomyces cerevisiae (Sigma Chemical Company) as template. The sequence of the nontemplate strand of plasmid pBB917 deduced from sequencing reactions with oBB60 as primer is shown on the right. The apparent transcription start site of gudB and the −10 and the −35 regions of the likely gudB promoter are indicated by outlined letters. Primer oBB57 gave the same apparent gudB mRNA 5′ end (data not shown). The direction of transcription is shown by the arrow.