An Hfq-dependent post-transcriptional mechanism fine tunes RecB expression in Escherichia coli
All living organisms have developed strategies to respond to chromosomal damage and preserve genome integrity. One such response is the repair of DNA double-strand breaks (DSBs), one of the most toxic forms of DNA lesions. In Escherichia coli, DSBs are repaired via RecBCD-dependent homologous recomb...
Saved in:
| Main Authors: | , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
eLife Sciences Publications Ltd
2025-08-01
|
| Series: | eLife |
| Subjects: | |
| Online Access: | https://elifesciences.org/articles/94918 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1849768501053489152 |
|---|---|
| author | Irina Kalita Ira Alexandra Iosub Lorna McLaren Louise Goossens Sander Granneman Meriem El Karoui |
| author_facet | Irina Kalita Ira Alexandra Iosub Lorna McLaren Louise Goossens Sander Granneman Meriem El Karoui |
| author_sort | Irina Kalita |
| collection | DOAJ |
| description | All living organisms have developed strategies to respond to chromosomal damage and preserve genome integrity. One such response is the repair of DNA double-strand breaks (DSBs), one of the most toxic forms of DNA lesions. In Escherichia coli, DSBs are repaired via RecBCD-dependent homologous recombination. RecBCD is essential for accurate chromosome maintenance, but its over-expression can lead to reduced DNA repair ability. This apparent paradox suggests that RecBCD copy numbers may need to be tightly controlled within an optimal range. Using single-molecule fluorescence microscopy, we have established that RecB is present in very low abundance at mRNA and protein levels. RecB transcription shows high fluctuations, yet cell-to-cell protein variability remains remarkably low. Here, we show that the post-transcriptional regulator Hfq binds to recB mRNA and downregulates RecB protein translation in vivo. Furthermore, specific disruption of the Hfq-binding site leads to more efficient translation of recB mRNAs. In addition, we observe a less effective reduction of RecB protein fluctuations in the absence of Hfq. This fine-tuning Hfq-mediated mechanism might have the underlying physiological function of maintaining RecB protein levels within an optimal range. |
| format | Article |
| id | doaj-art-dda3dc8d50df49a8b2060a7d7fc8b0af |
| institution | DOAJ |
| issn | 2050-084X |
| language | English |
| publishDate | 2025-08-01 |
| publisher | eLife Sciences Publications Ltd |
| record_format | Article |
| series | eLife |
| spelling | doaj-art-dda3dc8d50df49a8b2060a7d7fc8b0af2025-08-20T03:03:46ZengeLife Sciences Publications LtdeLife2050-084X2025-08-011310.7554/eLife.94918An Hfq-dependent post-transcriptional mechanism fine tunes RecB expression in Escherichia coliIrina Kalita0https://orcid.org/0000-0002-0127-077XIra Alexandra Iosub1Lorna McLaren2Louise Goossens3Sander Granneman4Meriem El Karoui5https://orcid.org/0000-0003-2522-613XCentre for Engineering Biology, University of Edinburgh, Edinburgh, United Kingdom; Institute of Cell Biology, University of Edinburgh, Edinburgh, United Kingdom; Max Planck Institute for Terrestrial Microbiology & Center for Synthetic Microbiology (SYNMIKRO), Marburg, GermanyCentre for Engineering Biology, University of Edinburgh, Edinburgh, United Kingdom; Institute of Quantitative Biology, Biochemistry and Biotechnology, University of Edinburgh, Edinburgh, United Kingdom; The Francis Crick Institute, London, United KingdomCentre for Engineering Biology, University of Edinburgh, Edinburgh, United Kingdom; Institute of Cell Biology, University of Edinburgh, Edinburgh, United KingdomCentre for Engineering Biology, University of Edinburgh, Edinburgh, United Kingdom; Institute of Cell Biology, University of Edinburgh, Edinburgh, United KingdomCentre for Engineering Biology, University of Edinburgh, Edinburgh, United Kingdom; Institute of Quantitative Biology, Biochemistry and Biotechnology, University of Edinburgh, Edinburgh, United KingdomCentre for Engineering Biology, University of Edinburgh, Edinburgh, United Kingdom; Institute of Cell Biology, University of Edinburgh, Edinburgh, United KingdomAll living organisms have developed strategies to respond to chromosomal damage and preserve genome integrity. One such response is the repair of DNA double-strand breaks (DSBs), one of the most toxic forms of DNA lesions. In Escherichia coli, DSBs are repaired via RecBCD-dependent homologous recombination. RecBCD is essential for accurate chromosome maintenance, but its over-expression can lead to reduced DNA repair ability. This apparent paradox suggests that RecBCD copy numbers may need to be tightly controlled within an optimal range. Using single-molecule fluorescence microscopy, we have established that RecB is present in very low abundance at mRNA and protein levels. RecB transcription shows high fluctuations, yet cell-to-cell protein variability remains remarkably low. Here, we show that the post-transcriptional regulator Hfq binds to recB mRNA and downregulates RecB protein translation in vivo. Furthermore, specific disruption of the Hfq-binding site leads to more efficient translation of recB mRNAs. In addition, we observe a less effective reduction of RecB protein fluctuations in the absence of Hfq. This fine-tuning Hfq-mediated mechanism might have the underlying physiological function of maintaining RecB protein levels within an optimal range.https://elifesciences.org/articles/94918RecBCD enzymeDNA repairHfq proteinpost-transcriptional regulationnoise suppression |
| spellingShingle | Irina Kalita Ira Alexandra Iosub Lorna McLaren Louise Goossens Sander Granneman Meriem El Karoui An Hfq-dependent post-transcriptional mechanism fine tunes RecB expression in Escherichia coli eLife RecBCD enzyme DNA repair Hfq protein post-transcriptional regulation noise suppression |
| title | An Hfq-dependent post-transcriptional mechanism fine tunes RecB expression in Escherichia coli |
| title_full | An Hfq-dependent post-transcriptional mechanism fine tunes RecB expression in Escherichia coli |
| title_fullStr | An Hfq-dependent post-transcriptional mechanism fine tunes RecB expression in Escherichia coli |
| title_full_unstemmed | An Hfq-dependent post-transcriptional mechanism fine tunes RecB expression in Escherichia coli |
| title_short | An Hfq-dependent post-transcriptional mechanism fine tunes RecB expression in Escherichia coli |
| title_sort | hfq dependent post transcriptional mechanism fine tunes recb expression in escherichia coli |
| topic | RecBCD enzyme DNA repair Hfq protein post-transcriptional regulation noise suppression |
| url | https://elifesciences.org/articles/94918 |
| work_keys_str_mv | AT irinakalita anhfqdependentposttranscriptionalmechanismfinetunesrecbexpressioninescherichiacoli AT iraalexandraiosub anhfqdependentposttranscriptionalmechanismfinetunesrecbexpressioninescherichiacoli AT lornamclaren anhfqdependentposttranscriptionalmechanismfinetunesrecbexpressioninescherichiacoli AT louisegoossens anhfqdependentposttranscriptionalmechanismfinetunesrecbexpressioninescherichiacoli AT sandergranneman anhfqdependentposttranscriptionalmechanismfinetunesrecbexpressioninescherichiacoli AT meriemelkaroui anhfqdependentposttranscriptionalmechanismfinetunesrecbexpressioninescherichiacoli AT irinakalita hfqdependentposttranscriptionalmechanismfinetunesrecbexpressioninescherichiacoli AT iraalexandraiosub hfqdependentposttranscriptionalmechanismfinetunesrecbexpressioninescherichiacoli AT lornamclaren hfqdependentposttranscriptionalmechanismfinetunesrecbexpressioninescherichiacoli AT louisegoossens hfqdependentposttranscriptionalmechanismfinetunesrecbexpressioninescherichiacoli AT sandergranneman hfqdependentposttranscriptionalmechanismfinetunesrecbexpressioninescherichiacoli AT meriemelkaroui hfqdependentposttranscriptionalmechanismfinetunesrecbexpressioninescherichiacoli |