Efficiency of transcription from promoter sequence variants in Lactobacillus is both strain and context dependent

The introduction of consensus -35 (TTGACA) and -10 (TATAAT) hexamers and a TG motif into the Lactobacillus acidophilus ATCC 4356 wild-type slpA promot er resulted in significant improvements (4.3-, 4.1-, and 10.7-fold, respect ively) in transcriptional activity in Lactobacillus fermentum BR11. In cont rast, the same changes resulted in decreased transcription in Lactobacillus rhamnosus GG. The TG motif was shown to be important in the context of wea k -35 and -10 hexamers (L. fermentum BR11) or a consensus -10 hexamer (L. r hamnosus GG). Thus, both strain- and context-dependent effects are critical factors influencing transcription in Lactobacillus.