The effect of DNA-binding proteins on insertion sequence element transposition upstream of the bgl operon in Escherichia coli .
| Autor: | Kopkowski PW; Department of Molecular Biology, School of Biological Sciences, University of California, San Diego, La Jolla, CA, United States., Zhang Z; Department of Molecular Biology, School of Biological Sciences, University of California, San Diego, La Jolla, CA, United States., Saier MH Jr; Department of Molecular Biology, School of Biological Sciences, University of California, San Diego, La Jolla, CA, United States. |
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| Jazyk: | angličtina |
| Zdroj: | Frontiers in microbiology [Front Microbiol] 2024 Apr 11; Vol. 15, pp. 1388522. Date of Electronic Publication: 2024 Apr 11 (Print Publication: 2024). |
| DOI: | 10.3389/fmicb.2024.1388522 |
| Abstrakt: | The bglGFB operon in Escherichia coli K-12 strain BW25113, encoding the proteins necessary for the uptake and metabolism of β-glucosides, is normally not expressed. Insertion of either IS1 or IS5 upstream of the bgl promoter activates expression of the operon only when the cell is starving in the presence of a β-glucoside, drastically increasing transcription and allowing the cell to survive and grow using this carbon source. Details surrounding the exact mechanism and regulation of the IS insertional event remain unclear. In this work, the role of several DNA-binding proteins in how they affect the rate of insertion upstream of bgl are examined via mutation assays and protocols measuring transcription. Both Crp and IHF exert a positive effect on insertional Bgl + mutations when present, active, and functional in the cell. Our results characterize IHF's effect in conjunction with other mutations, show that IHF's effect on IS insertion into bgl also affects other operons, and indicate that it may exert its effect by binding to and altering the DNA conformation of IS1 and IS5 in their native locations, rather than by directly influencing transposase gene expression. In contrast, the cAMP-CRP complex acts directly upon the bgl operon by binding upstream of the promoter, presumably altering local DNA into a conformation that enhances IS insertion. Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. (Copyright © 2024 Kopkowski, Zhang and Saier.) |
| Databáze: | MEDLINE |
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