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Jeon HJ, Monford Paul Abishek N, Lee Y, Park J, Lim HM. Transcription Needs Translation Initiation of the Downstream Gene to Continue Downstream at Intercistronic Junctions in E. Coli. Curr Microbiol 2024; 81:89. [PMID: 38311680 DOI: 10.1007/s00284-023-03592-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2023] [Accepted: 12/14/2023] [Indexed: 02/06/2024]
Abstract
We have reported a gal mutant called galE stop0, wherein the galE stop codon was changed to a sense codon. The experiment results demonstrated that preventing galE translation termination inhibited the production of galE 3' ends. This implies that when the galE translation termination was prevented, the galE 3' ends generation was reduced or impaired. We anticipated that the translation of galE would continue to galT, producing a chimeric protein GalE-GalT. This study verified that the chimeric protein was produced, but unexpectedly, we found that the GalT protein was also synthesized in the mutant, and its amount equaled that in the wild-type. In the wild-type, we also found that the GalE-GalT chimeric protein was produced in an amount equal to that of the GalE protein. These results suggest that translation termination of galE and translation initiation of galT occur independently, thus, corroborating our transcription-translation model: At the cistron junction, transcription, decoupled from translation due to the translation termination of galE, needs translation initiation of galT to continue downstream; otherwise, transcription would be terminated by Rho. RNase E-mediated transcript cleavage also produces the 3' ends of pre-galE mRNA. These findings indicated that RNase E produces the 3' end of mRNA and establishes gene expression polarity.
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Affiliation(s)
- Heung Jin Jeon
- Department of Biological Sciences, College of Biological Sciences and Biotechnology, Chungnam National University, Daejeon, 34134, Republic of Korea.
- Infection Control Convergence Research Center, Chungnam National University College of Medicine, Daejeon, 35015, Republic of Korea.
| | - N Monford Paul Abishek
- Department of Biological Sciences, College of Biological Sciences and Biotechnology, Chungnam National University, Daejeon, 34134, Republic of Korea
| | - Yonho Lee
- Department of Biological Sciences, College of Biological Sciences and Biotechnology, Chungnam National University, Daejeon, 34134, Republic of Korea
| | - Jeongok Park
- Department of Biological Sciences, College of Biological Sciences and Biotechnology, Chungnam National University, Daejeon, 34134, Republic of Korea
| | - Heon M Lim
- Department of Biological Sciences, College of Biological Sciences and Biotechnology, Chungnam National University, Daejeon, 34134, Republic of Korea.
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Liu J, Cui L, Shi X, Yan J, Wang Y, Ni Y, He J, Wang X. Generation of DNAzyme in Bacterial Cells by a Bacterial Retron System. ACS Synth Biol 2024; 13:300-309. [PMID: 38171507 DOI: 10.1021/acssynbio.3c00509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
DNAzymes are catalytically active single-stranded DNAs in which DNAzyme 10-23 (Dz 10-23) consists of a catalytic core and a substrate-binding arm that reduces gene expression through sequence-specific mRNA cleavage. However, the in vivo application of Dz 10-23 depends on exogenous delivery, which leads to its inability to be synthesized and stabilized in vivo, thus limiting its application. As a unique reverse transcription system, the bacterial retron system can synthesize single-stranded DNA in vivo using ncRNA msr/msd as a template. The objective of this work is to reduce target gene expression using Dz 10-23 generated in vivo by the retron system. In this regard, we successfully generated Dz 10-23 by cloning the Dz 10-23 coding sequence into the retron msd gene and tested its ability to reduce specific gene expression by examining the mRNA levels of cfp encoding cyan fluorescence protein and other functional genes such as mreB and ftsZ. We found that Dz had different repressive effects when targeting different mRNA regions, and in general, the repressive effect was stronger when targeting downstream of mRNAs. Our results also suggested that the reduction effect was due to cleavage of the substrate mRNA by Dz 10-23 rather than the antisense effect of the substrate-binding arm. Therefore, this study not only provided a retron-based method for the intracellular generation of Dz 10-23 but also demonstrated that Dz 10-23 could reduce gene expression by cleaving target mRNAs in cells. We believe that this new strategy would have great potential in the regulation of gene expression.
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Affiliation(s)
- Jie Liu
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Lina Cui
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Xinyu Shi
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Jiahao Yan
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Yifei Wang
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Yuyang Ni
- College of Life Sciences, Shangrao Normal University, Shangrao 334001, PR China
| | - Jin He
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Xun Wang
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China
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Clarke JE, Sabharwal K, Kime L, McDowall KJ. The recognition of structured elements by a conserved groove distant from domains associated with catalysis is an essential determinant of RNase E. Nucleic Acids Res 2023; 51:365-379. [PMID: 36594161 PMCID: PMC9841416 DOI: 10.1093/nar/gkac1228] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 11/11/2022] [Accepted: 12/08/2022] [Indexed: 01/04/2023] Open
Abstract
RNase E is an endoribonuclease found in many bacteria, including important human pathogens. Within Escherichia coli, it has been shown to have a major role in both the maturation of all classes of RNA involved in translation and the initiation of mRNA degradation. Thus, knowledge of the major determinants of RNase E cleavage is central to our understanding and manipulation of bacterial gene expression. We show here that the binding of RNase E to structured RNA elements is crucial for the processing of tRNA, can activate catalysis and may be important in mRNA degradation. The recognition of structured elements by RNase E is mediated by a recently discovered groove that is distant from the domains associated with catalysis. The functioning of this groove is shown here to be essential for E. coli cell viability and may represent a key point of evolutionary divergence from the paralogous RNase G family, which we show lack amino acid residues conserved within the RNA-binding groove of members of the RNase E family. Overall, this work provides new insights into the recognition and cleavage of RNA by RNase E and provides further understanding of the basis of RNase E essentiality in E. coli.
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Affiliation(s)
| | | | - Louise Kime
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Kenneth J McDowall
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
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Jeon HJ, Lee Y, N MPA, Kang C, Lim HM. sRNA expedites polycistronic mRNA decay in Escherichia coli. Front Mol Biosci 2023; 10:1097609. [PMID: 36936984 PMCID: PMC10020718 DOI: 10.3389/fmolb.2023.1097609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Accepted: 02/23/2023] [Indexed: 03/06/2023] Open
Abstract
In bacteria, most small RNA (sRNA) elicits RNase E-mediated target mRNA degradation by binding near the translation initiation site at the 5' end of the target mRNA. Spot 42 is an sRNA that binds in the middle of the gal operon near the translation initiation site of galK, the third gene of four, but it is not clear whether this binding causes degradation of gal mRNA. In this study, we measured the decay rate of gal mRNA using Northern blot and found that Spot 42 binding caused degradation of only a specific group of gal mRNA that shares their 3' end with full-length mRNA. The results showed that in the MG1655Δspf strain in which the Spot 42 gene was removed, the half-life of each gal mRNA in the group increased by about 200% compared to the wild type. Since these mRNA species are intermediate mRNA molecules created by the decay process of the full-length gal mRNA, these results suggest that sRNA accelerates the mRNA decaying processes that normally operate, thus revealing an unprecedented role of sRNA in mRNA biology.
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Affiliation(s)
- Heung Jin Jeon
- Department of Biological Sciences, College of Biological Sciences and Biotechnology, Chungnam National University, Daejeon, Republic of Korea
- Infection Control Convergence Research Center, College of Medicine, Chungnam National University, Daejeon, Republic of Korea
- *Correspondence: Heung Jin Jeon, ; Heon M. Lim,
| | - Yonho Lee
- Department of Biological Sciences, College of Biological Sciences and Biotechnology, Chungnam National University, Daejeon, Republic of Korea
| | - Monford Paul Abishek N
- Department of Biological Sciences, College of Biological Sciences and Biotechnology, Chungnam National University, Daejeon, Republic of Korea
| | - Changjo Kang
- Department of Biological Sciences, College of Biological Sciences and Biotechnology, Chungnam National University, Daejeon, Republic of Korea
| | - Heon M. Lim
- Department of Biological Sciences, College of Biological Sciences and Biotechnology, Chungnam National University, Daejeon, Republic of Korea
- *Correspondence: Heung Jin Jeon, ; Heon M. Lim,
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Otoupal PB, Cress BF, Doudna JA, Schoeniger J. CRISPR-RNAa: targeted activation of translation using dCas13 fusions to translation initiation factors. Nucleic Acids Res 2022; 50:8986-8998. [PMID: 35950485 PMCID: PMC9410913 DOI: 10.1093/nar/gkac680] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 07/19/2022] [Accepted: 08/05/2022] [Indexed: 12/24/2022] Open
Abstract
Tools for synthetically controlling gene expression are a cornerstone of genetic engineering. CRISPRi and CRISPRa technologies have been applied extensively for programmable modulation of gene transcription, but there are few such tools for targeted modulation of protein translation rates. Here, we employ CRISPR-Cas13 as a programmable activator of translation. We develop a novel variant of the catalytically-deactivated Cas13d enzyme dCasRx by fusing it to translation initiation factor IF3. We demonstrate dCasRx-IF3's ability to enhance expression 21.3-fold above dCasRx when both are targeted to the start of the 5' untranslated region of mRNA encoding red fluorescent protein in Escherichia coli. Activation of translation is location-dependent, and we show dCasRx-IF3 represses translation when targeted to the ribosomal binding site, rather than enhancing it. We provide evidence that dCasRx-IF3 targeting enhances mRNA stability relative to dCasRx, providing mechanistic insights into how this new tool functions to enhance gene expression. We also demonstrate targeted upregulation of native LacZ 2.6-fold, showing dCasRx-IF3's ability to enhance expression of endogenous genes. dCasRx-IF3 requires no additional host modification to influence gene expression. This work outlines a novel approach, CRISPR-RNAa, for post-transcriptional control of translation to activate gene expression.
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Affiliation(s)
| | - Brady F Cress
- Innovative Genomics Institute, University of California, Berkeley, CA, USA,Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Jennifer A Doudna
- Innovative Genomics Institute, University of California, Berkeley, CA, USA,Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA,California Institute for Quantitative Biosciences, University of California, Berkeley, CA, USA,Department of Chemistry, University of California, Berkeley, CA, USA,Howard Hughes Medical Institute, University of California, Berkeley, CA, USA,Molecular Biophysics & Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA,Gladstone Institutes, University of California, San Francisco, CA, USA
| | - Joseph S Schoeniger
- To whom correspondence should be addressed. Tel: +1 925 294 2955; Fax: +1 925 294 3020;
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N MPA, Lim HM. An in vitro Assay of mRNA 3' end Using the E. coli Cell-free Expression System. Bio Protoc 2022; 12:e4333. [PMID: 35340297 PMCID: PMC8899560 DOI: 10.21769/bioprotoc.4333] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 12/01/2021] [Accepted: 01/27/2022] [Indexed: 11/25/2023] Open
Abstract
At the end of about 80% of the operon in Escherichia coli, translation termination decouples transcription, leading to Rho-dependent transcription termination (RDT). However, no in vitro or in vivo assay system has proven to be good enough to see the 3' end of the mRNA generated by RDT. Here, we present a cell-free assay system that could provide detailed information on the 3' end of a transcript RNA generated by RDT. Our protocol shows how to extract transcript RNA generated by transcription reactions from a cell-free extract, followed by an RNA oligomer ligation to the 3' end of a transcript RNA of interest. The 3' end of the RNA is amplified using RT-PCR. Its genetic location can be determined using a gene-specific primer extension reaction. The 3' ends of mRNA can be visualized and quantified by polyacrylamide gel electrophoresis. One significant advantage of a cell-free assay system is that factors involved in the generation of the 3' end, such as proteins and sRNA, can be directly assayed by exogenously adding factor(s) to the reaction. Graphic abstract: An illustration of the experimental methodology.
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Affiliation(s)
- Monford Paul Abishek N
- Department of Biological Sciences, College of Biosciences and Biotechnology, Chungnam National University, Daejeon 34134, Republic of Korea
| | - Heon M. Lim
- Department of Biological Sciences, College of Biosciences and Biotechnology, Chungnam National University, Daejeon 34134, Republic of Korea
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