Analysis of acid-induced asr gene promoter of Enterobacteriaceae

Abstract

Enterobacteria in response to an external acidification strongly induce the transcription of asr gene. In this study mutational analysis of E. Coli asr promoter has been performed to locate regions important for acidtriggered transcriptional activation. Our study revealed that deletions within the predicted pho box located at the –21/–38 region of the asr promoter did not absolutely abolish acid-induced transcription indicating the existence of additional cis-regulatory elements involved in transcription regulation. Moreover, the consecutive deletions of upstream sequences located in the –40/–70 region were found important for the acid-triggered transcriptional activation of asr. A comparative sequence analysis of the promoter region of asr gene homologues of other enterobacteria demonstrated a high degree of conservation suggesting a common environmental stress-induced regulatory pathway. Keywords: acid stress, Enterobacteriaceae, E. coli asr promoter, mutational analysis