Revision as of 03:32, 8 October 2023

arsR coding sequence, Escherichia coli chromosomal ars repressor

Escherichia coli chromosomal arsR coding sequence, which encodes the ArsR repressor. This binds to the ars promoter and represses it in the absence of arsenate or arsenite (Cai, J., and DuBow, M.S. 1996. Expression of the Escherichia coli chromosomal ars operon. Canadian Journal of Microbiology 42, 662-671; Diorio, C., Cai, J., Marmor, J., Shinder, R., and DuBow, M.S. 1995. An Escherichia coli chromosomal ars operon homolog is functional in arsenic detoxification and is conserved in Gram negative bacteria. Journal of Bacteriology 177, 2050-2056).

Usage and Biology

CUG-China 2023--Improvement

A relatively well-studied arsenic resistance operon is the one found in Escherichia coli, which contains arsR (transcriptional regulator), arsB (arsenite permease), and arsC (arsenate reductase). When arsenic is absent, the transcription regulator ArsR binds to the ArsR-binding site (ABS) within the ars promoter and blocks transcription. Once arsenic is present, it binds to ArsR and activate the transcription of the ars genes and clear arsenic in the cell. The arsR regulator and the promoter of this operon have been used to construct arsenic whole cell biosensors (WCB) in various microorganism hosts.

When arsenic is absent, the transcription regulator ArsR binds to the ArsR-binding site (ABS) within the ars promoter and blocks transcription. Once arsenic is present, it binds to ArsR and activate the transcription of the downstream genes. We used gfp as a reporter to test its function of arsenic detection. Since this ars system comes from E. coli genome, to eliminate this impact, we used another model bacteria Shewanella oneidensis as the chassis cells to verify the function of this part. As the result shows below, with the arsenic concentration rises, the strain with the reporter produced higher fluorescence intensity.

Fig. Fluorescence curve of the reporter strain with different arsenic concentrations

[1]Yidan Hu, Wang Yinghui, Han Xi, et al. Biofilm Biology and Engineering of Geobacter and Shewanella spp. for Energy Applications[J]. Frontiers in Bioengineering and Biotechnology, 2021, 9.

[2]Liang Shi, Dong Hailiang, Reguera Gemma, et al. Extracellular electron transfer mechanisms between microorganisms and minerals[J]. Nature Reviews Microbiology, 2016, 14(10): 651-662.

This experience was added by the CUG-China 2023.

Sequence and Features