Heterologous expression of the gene for chlorite dismutase from Ideonella dechloratans is induced by an FNR ‐type transcription factor

Activation of the chlorite dismutase (cld) gene, located in the chlorate composite transposon of the chlorate reducerIdeonella dechloratans, was studied in a transcriptional reporter system in anfnr‐deficientEscherichia coli strain. The results demonstrate that anfnr‐type regulator ofI. dechloratans, not present in the chlorate composite transposon, induces this gene under anaerobic conditions. Implications for horizontal gene transfer of the capability of dissimilatory chlorate reduction are discussed. AbstractRegulation of the expression of the gene for chlorite dismutase (cld), located on the chlorate reduction composite transposon of the chlorate reducerIdeonella dechloratans, was studied. A 200  bp upstream sequence of thecld gene, and mutated and truncated versions thereof, was used in a reporter system inEscherichia coli. It was found that a sequence within this upstream region, which is nearly identical to the canonical FNR ‐binding sequence ofE.coli, is necessary for anaerobic induction of the reporter gene. Anaerobic induction was regained in an FNR ‐deficient strain ofE. coli when supplemented either with thefnr gene fromE. coli or with a candidatefnr gene cloned fromI. dechloratans. In vivo transcription of the suggestedfnr gene ofI. dechloratans was demonstrated by qRT ‐PCR. Based on these results, thecld promoter ofI. dechloratans is suggested to be a class II ‐activated promoter regulated by an FNR‐type protein ofI. dechloratans. Nofnr‐type gen...
Source: MicrobiologyOpen - Category: Microbiology Authors: Tags: ORIGINAL ARTICLE Source Type: research