FIG. 2.

Relative strengths of individual promoter elements as determined by primer extension analysis. Total RNA was isolated from strains containing the indicated promoter-lacZ fusion constructs and was used for primer extension analysis with a ³²P-labeled primer that hybridizes to the spoVG-lacZ junction present in the constructs. Primer extension products were separated by gel electrophoresis, and arbitrary values were calculated from densitometric scans of autoradiograms. Transcripts initiating at P1 or P2 were quantitated separately. Each experiment was repeated at least 3 times. Error bars represent the standard errors of the means.