1
|
Lee K, Yoon H, Park OS, Lim J, Kim SG, Seo PJ. The ESR2-HDA6 complex exerts negative feedback regulation of auxin biosynthesis to delay callus initiation from Arabidopsis leaf explants during tissue culture. Plant Commun 2024:100892. [PMID: 38566417 DOI: 10.1016/j.xplc.2024.100892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 03/27/2024] [Accepted: 04/01/2024] [Indexed: 04/04/2024]
Abstract
Plants exhibit an astonishing ability to regulate organ regeneration upon wounding. Excision of leaf explants promotes biosynthesis of indole-3-acetic acid (IAA), which is polar-transported to excised regions, where cell fate transition leads to specification of root founder cells to induce de novo root regeneration. The regeneration capacity of plants has been utilized to develop in vitro tissue culture technology. Here, we report that IAA accumulation near wounded site of leaf explants is essential for induction of callus on 2,4-dichlorophenoxyacetic acid (2,4-D)-rich callus-inducing medium (CIM). Notably, a high concentration of a synthetic auxin, 2,4-D, does not compensate for IAA action because of its limited efflux; rather, it lowers IAA biosynthesis via a negative feedback mechanism at an early stage of in vitro tissue culture, delaying callus initiation. The auxin negative feedback loop in CIM-cultured leaf explants is mediated by an auxin-inducible AP2 transcription factor, ENHANCER OF SHOOT REGENERATION 2 (ESR2), and its interacting partner HISTONE DEACETYLASE 6 (HDA6). The ESR2-HDA6 complex binds directly to, and removes the H3ac mark from, the YUCCA1 (YUC1), YUC7, and YUC9 loci, consequently repressing auxin biosynthesis and inhibiting cell fate transition on 2,4-D-rich CIM. These findings indicate that negative feedback regulation of auxin biosynthesis by ESR2 and HDA6 interferes with proper cell fate transition and callus initiation.
Collapse
Affiliation(s)
- Kyounghee Lee
- Department of Chemistry, Seoul National University, Seoul 08826, Korea; Research Institute of Basic Sciences, Seoul National University, Seoul 08826, Korea
| | - Hobin Yoon
- Interdisciplinary Program in Agricultural Biotechnology, Seoul National University, Seoul 08826, Korea
| | - Ok-Sun Park
- Plant Genomics and Breeding Institute, Seoul National University, Seoul 08826, Korea
| | - Jongbu Lim
- Department of Biological Sciences, KAIST, Daejeon 34141, Korea
| | - Sang-Gyu Kim
- Department of Biological Sciences, KAIST, Daejeon 34141, Korea
| | - Pil Joon Seo
- Department of Chemistry, Seoul National University, Seoul 08826, Korea; Research Institute of Basic Sciences, Seoul National University, Seoul 08826, Korea; Interdisciplinary Program in Agricultural Biotechnology, Seoul National University, Seoul 08826, Korea; Plant Genomics and Breeding Institute, Seoul National University, Seoul 08826, Korea.
| |
Collapse
|
2
|
McKenna JA, Karney MMA, Chan DK, Weatherspoon-Griffin N, Becerra Larios B, Pilonieta MC, Munson GP, Wing HJ. The AraC/XylS Protein MxiE and Its Coregulator IpgC Control a Negative Feedback Loop in the Transcriptional Cascade That Regulates Type III Secretion in Shigella flexneri. J Bacteriol 2022;:e0013722. [PMID: 35703565 DOI: 10.1128/jb.00137-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Members of the AraC family of transcriptional regulators (AFTRs) control the expression of many genes important to cellular processes, including virulence. In Shigella species, the type III secretion system (T3SS), a key determinant for host cell invasion, is regulated by the three-tiered VirF/VirB/MxiE transcriptional cascade. Both VirF and MxiE belong to the AFTRs and are characterized as positive transcriptional regulators. Here, we identify a novel regulatory activity for MxiE and its coregulator IpgC, which manifests as a negative feedback loop in the VirF/VirB/MxiE transcriptional cascade. Our findings show that MxiE and IpgC downregulate the virB promoter and, hence, VirB protein production, thus decreasing VirB-dependent promoter activity at ospD1, one of the nearly 50 VirB-dependent genes. At the virB promoter, regions required for negative MxiE- and IpgC-dependent regulation were mapped and found to be coincident with regions required for positive VirF-dependent regulation. In tandem, negative MxiE- and IpgC-dependent regulation of the virB promoter only occurred in the presence of VirF, suggesting that MxiE and IpgC can function to counter VirF activation of the virB promoter. Lastly, MxiE and IpgC do not downregulate another VirF-activated promoter, icsA, demonstrating that this negative feedback loop targets the virB promoter. Our study provides insight into a mechanism that may reprogram Shigella virulence gene expression following type III secretion and provides the impetus to examine if MxiE and IpgC homologs in other important bacterial pathogens, such as Burkholderia pseudomallei and Salmonella enterica serovars Typhimurium and Typhi, coordinate similar negative feedback loops. IMPORTANCE The large AraC family of transcriptional regulators (AFTRs) control virulence gene expression in many bacterial pathogens. In Shigella species, the AraC/XylS protein MxiE and its coregulator IpgC positively regulate the expression of type III secretion system genes within the three-tiered VirF/VirB/MxiE transcriptional cascade. Our findings suggest a negative feedback loop in the VirF/VirB/MxiE cascade, in which MxiE and IpgC counter VirF-dependent activation of the virB promoter, thus making this the first characterization of negative MxiE- and IpgC-dependent regulation. Our study provides insight into a mechanism that likely reprograms Shigella virulence gene expression following type III secretion, which has implications for other important bacterial pathogens with functional homologs of MxiE and IpgC.
Collapse
|
3
|
Jamsheer K M, Jindal S, Sharma M, Awasthi P, S S, Sharma M, Mannully CT, Laxmi A. A negative feedback loop of TOR signaling balances growth and stress-response trade-offs in plants. Cell Rep 2022; 39:110631. [PMID: 35385724 DOI: 10.1016/j.celrep.2022.110631] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 07/26/2021] [Accepted: 03/16/2022] [Indexed: 12/20/2022] Open
Abstract
TOR kinase is a central coordinator of nutrient-dependent growth in eukaryotes. Maintaining optimal TOR signaling is critical for the normal development of organisms. In this study, we describe a negative feedback loop of TOR signaling helping in the adaptability of plants in changing environmental conditions. Using an interdisciplinary approach, we show that the plant-specific zinc finger protein FLZ8 acts as a regulator of TOR signaling in Arabidopsis. In sugar sufficiency, TOR-dependent and -independent histone modifications upregulate the expression of FLZ8. FLZ8 negatively regulates TOR signaling by promoting antagonistic SnRK1α1 signaling and bridging the interaction of SnRK1α1 with RAPTOR1B, a crucial accessory protein of TOR. This negative feedback loop moderates the TOR-growth signaling axis in the favorable condition and helps in the activation of stress signaling in unfavorable conditions, establishing its importance in the adaptability of plants.
Collapse
Affiliation(s)
- Muhammed Jamsheer K
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi 110067, India.
| | - Sunita Jindal
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Mohan Sharma
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Prakhar Awasthi
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Sreejath S
- Department of Mechanical Engineering, Indian Institute of Technology Delhi, New Delhi 110016, India
| | - Manvi Sharma
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi 110067, India
| | | | - Ashverya Laxmi
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi 110067, India.
| |
Collapse
|
4
|
Abstract
A central theme that governs the functional design of biological networks is their ability to sustain stable function despite widespread parametric variability. Here, we investigated the impact of distinct forms of biological heterogeneities on the stability of a two-dimensional continuous attractor network (CAN) implicated in grid-patterned activity generation. We show that increasing degrees of biological heterogeneities progressively disrupted the emergence of grid-patterned activity and resulted in progressively large perturbations in low-frequency neural activity. We postulated that targeted suppression of low-frequency perturbations could ameliorate heterogeneity-induced disruptions of grid-patterned activity. To test this, we introduced intrinsic resonance, a physiological mechanism to suppress low-frequency activity, either by adding an additional high-pass filter (phenomenological) or by incorporating a slow negative feedback loop (mechanistic) into our model neurons. Strikingly, CAN models with resonating neurons were resilient to the incorporation of heterogeneities and exhibited stable grid-patterned firing. We found CAN models with mechanistic resonators to be more effective in targeted suppression of low-frequency activity, with the slow kinetics of the negative feedback loop essential in stabilizing these networks. As low-frequency perturbations (1/f noise) are pervasive across biological systems, our analyses suggest a universal role for mechanisms that suppress low-frequency activity in stabilizing heterogeneous biological networks.
Collapse
Affiliation(s)
- Divyansh Mittal
- Cellular Neurophysiology Laboratory, Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
| | - Rishikesh Narayanan
- Cellular Neurophysiology Laboratory, Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
| |
Collapse
|
5
|
Cardona Gloria Y, Bernhart SH, Fillinger S, Wolz OO, Dickhöfer S, Admard J, Ossowski S, Nahnsen S, Siebert R, Weber ANR. Absence of Non-Canonical, Inhibitory MYD88 Splice Variants in B Cell Lymphomas Correlates With Sustained NF-κB Signaling. Front Immunol 2021; 12:616451. [PMID: 34163463 PMCID: PMC8215704 DOI: 10.3389/fimmu.2021.616451] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 05/18/2021] [Indexed: 11/13/2022] Open
Abstract
Gain-of-function mutations of the TLR adaptor and oncoprotein MyD88 drive B cell lymphomagenesis via sustained NF-κB activation. In myeloid cells, both short and sustained TLR activation and NF-κB activation lead to the induction of inhibitory MYD88 splice variants that restrain prolonged NF-κB activation. We therefore sought to investigate whether such a negative feedback loop exists in B cells. Analyzing MYD88 splice variants in normal B cells and different primary B cell malignancies, we observed that MYD88 splice variants in transformed B cells are dominated by the canonical, strongly NF-κB-activating isoform of MYD88 and contain at least three novel, so far uncharacterized signaling-competent splice isoforms. Sustained TLR stimulation in B cells unexpectedly reinforces splicing of NF-κB-promoting, canonical isoforms rather than the 'MyD88s', a negative regulatory isoform reported to be typically induced by TLRs in myeloid cells. This suggests that an essential negative feedback loop restricting TLR signaling in myeloid cells at the level of alternative splicing, is missing in B cells when they undergo proliferation, rendering B cells vulnerable to sustained NF-κB activation and eventual lymphomagenesis. Our results uncover MYD88 alternative splicing as an unappreciated promoter of B cell lymphomagenesis and provide a rationale why oncogenic MYD88 mutations are exclusively found in B cells.
Collapse
Affiliation(s)
- Yamel Cardona Gloria
- Department of Immunology, University of Tübingen, Tübingen, Germany.,Cluster of Excellence iFIT (EXC 2180) "Image-Guided and Functionally Instructed Tumor Therapies", University of Tübingen, Tübingen, Germany
| | - Stephan H Bernhart
- Interdisciplinary Center for Bioinformatics, University of Leipzig, Leipzig, Germany.,Bioinformatics Group, Department of Computer, University of Leipzig, Leipzig, Germany.,Transcriptome Bioinformatics, Leipzig Research Center for Civilization Diseases (LIFE), University of Leipzig, Leipzig, Germany
| | - Sven Fillinger
- Quantitative Biology Center (QBiC), University of Tübingen, Tübingen, Germany
| | - Olaf-Oliver Wolz
- Department of Immunology, University of Tübingen, Tübingen, Germany.,Cluster of Excellence iFIT (EXC 2180) "Image-Guided and Functionally Instructed Tumor Therapies", University of Tübingen, Tübingen, Germany
| | - Sabine Dickhöfer
- Department of Immunology, University of Tübingen, Tübingen, Germany.,Cluster of Excellence iFIT (EXC 2180) "Image-Guided and Functionally Instructed Tumor Therapies", University of Tübingen, Tübingen, Germany
| | - Jakob Admard
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany
| | - Stephan Ossowski
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany
| | - Sven Nahnsen
- Quantitative Biology Center (QBiC), University of Tübingen, Tübingen, Germany
| | - Reiner Siebert
- Institute of Human Genetics, Ulm University and Ulm University Medical Center, Ulm, Germany.,Institute of Human Genetics, Christian-Albrechts-University, Kiel, Germany
| | - Alexander N R Weber
- Department of Immunology, University of Tübingen, Tübingen, Germany.,Cluster of Excellence iFIT (EXC 2180) "Image-Guided and Functionally Instructed Tumor Therapies", University of Tübingen, Tübingen, Germany.,Deutsches Konsortium für Translationale Krebsforschung (DKTK; German Cancer Consortium), Partner Site Tübingen, Department of Immunology, University of Tübingen, Tübingen, Germany
| |
Collapse
|
6
|
Beesley S, Kim DW, D'Alessandro M, Jin Y, Lee K, Joo H, Young Y, Tomko RJ Jr, Faulkner J, Gamsby J, Kim JK, Lee C. Wake-sleep cycles are severely disrupted by diseases affecting cytoplasmic homeostasis. Proc Natl Acad Sci U S A 2020; 117:28402-11. [PMID: 33106420 DOI: 10.1073/pnas.2003524117] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Circadian rhythms including wake-sleep cycles are driven by molecular time cues generated by a self-sustaining transcriptional negative feedback loop. Among all clock proteins, PERIOD (PER) is considered the pacemaker protein because its rhythm of accumulation and nuclear entry generates the timing and duration of feedback inhibition. Here we provide a new understanding of how robust PER rhythms are generated: the collective action of interacting PER molecules, not a random mass action of individual molecules, allows compensation of spatial and temporal differences (or “noise”) of individual molecules. We also show that the collective PER rhythm requires healthy cytoplasmic trafficking, and that circadian sleep disorders can arise in such conditions as obesity, aging, and neurodegenerative disorders in which the cytoplasm becomes congested. The circadian clock is based on a transcriptional feedback loop with an essential time delay before feedback inhibition. Previous work has shown that PERIOD (PER) proteins generate circadian time cues through rhythmic nuclear accumulation of the inhibitor complex and subsequent interaction with the activator complex in the feedback loop. Although this temporal manifestation of the feedback inhibition is the direct consequence of PER’s cytoplasmic trafficking before nuclear entry, how this spatial regulation of the pacemaker affects circadian timing has been largely unexplored. Here we show that circadian rhythms, including wake-sleep cycles, are lengthened and severely unstable if the cytoplasmic trafficking of PER is disrupted by any disease condition that leads to increased congestion in the cytoplasm. Furthermore, we found that the time delay and robustness in the circadian clock are seamlessly generated by delayed and collective phosphorylation of PER molecules, followed by synchronous nuclear entry. These results provide clear mechanistic insight into why circadian and sleep disorders arise in such clinical conditions as metabolic and neurodegenerative diseases and aging, in which the cytoplasm is congested.
Collapse
|
7
|
Huang Q, Zhang F, Fu H, Shen J. Epigenetic regulation of miR-518a-5p-CCR6 feedback loop promotes both proliferation and invasion in diffuse large B cell lymphoma. Epigenetics 2020; 16:28-44. [PMID: 32600091 DOI: 10.1080/15592294.2020.1786317] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
To investigate the detailed functions and underlying mechanisms of miR-518a-5p/CCR6 in diffuse large B cell lymphoma (DLBCL) is needed. In this study, CCR6 expression levels were tested both in DLBCL cell lines and specimens. Through bioinformatics analysis and quantitative real-time PCR (qRT-PCR) validation, CCR6's targeted miRNA was obtained. Dual luciferase assay was used to verify their targeted relationship. Futhermore, using qRT-PCR, western blot, CCK8, Transwell assays, flow cytometry, pyrosequencing, chromatin immunoprecipitation, and azacitidine/C646 treatment, the detailed functions and underlying mechanisms of CCR6 and its targeted miRNA in DLBCL were detected. We found that negative correlation existed between CCR6 and miR-518a-5p in DLBCL. Both up-regulated miR-518a-5p and down-regulated CCR6 inhibited cell proliferation and invasion in vitro. Experiment then verified the regulatory relationship between miR-518a-5p and CCR6. JAK2 and STAT6 levels were reduced in DLBCL cells transfected with miR-518a-5p mimic or CCR6 small interfering RNA. Interestingly, we showed for the first time that a hyper-methylated condition existed at the promoter region of miR-518a-5p and azacitidine changed levels of miR-518a-5p in a time- and concentration-dependent manner. Finally, we found an enriched histone H3 on lysine 27 acetylation existed in the promoter of CCR6, whose expression could also be changed via C646 in a time- and concentration-dependent manner. The above results suggest that miR-518a-5p-CCR6 feedback loop plays a critical role in DLBCL development. The overexpression of CCR6 is mainly mediated by epigenetic modification through transcriptional and post-transcriptional activation, which provides new directions for DLBCL treatment.
Collapse
Affiliation(s)
- Qian Huang
- Department of Hematology, Fujian Provincial Key Laboratory of Hematology, Fujian Medical University Union Hospital , Fuzhou, Fujian, People's Republic of China
| | - Feng Zhang
- Department of Hematology, Fujian Provincial Key Laboratory of Hematology, Fujian Medical University Union Hospital , Fuzhou, Fujian, People's Republic of China
| | - Haiying Fu
- Department of Hematology, Fujian Provincial Key Laboratory of Hematology, Fujian Medical University Union Hospital , Fuzhou, Fujian, People's Republic of China
| | - Jianzhen Shen
- Department of Hematology, Fujian Provincial Key Laboratory of Hematology, Fujian Medical University Union Hospital , Fuzhou, Fujian, People's Republic of China
| |
Collapse
|
8
|
Abstract
The red blood cell (RBC) membrane contains a mechanosensitive cation channel Piezo1 that is involved in RBC volume homeostasis. In a recent model of the mechanism of its action it was proposed that Piezo1 cation permeability responds to changes of the RBC shape. The aim here is to review in a descriptive manner different previous studies of RBC behavior that formed the basis for this proposal. These studies include the interpretation of RBC and vesicle shapes based on the minimization of membrane bending energy, the analyses of various consequences of compositional and structural features of RBC membrane, in particular of its membrane skeleton and its integral membrane proteins, and the modeling of the establishment of RBC volume. The proposed model of Piezo1 action is critically evaluated, and a perspective presented for solving some remaining experimental and theoretical problems. Part of the discussion is devoted to the usefulness of theoretical modeling in studies of the behavior of cell systems in general.
Collapse
Affiliation(s)
- Saša Svetina
- Institute of Biophysics, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia.,Jožef Stefan Institute, Ljubljana, Slovenia
| |
Collapse
|
9
|
Khan MA, Durica-Mitic S, Göpel Y, Heermann R, Görke B. Small RNA-binding protein RapZ mediates cell envelope precursor sensing and signaling in Escherichia coli. EMBO J 2020; 39:e103848. [PMID: 32065419 PMCID: PMC7073468 DOI: 10.15252/embj.2019103848] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 01/21/2020] [Accepted: 01/24/2020] [Indexed: 11/24/2022] Open
Abstract
The RNA‐binding protein RapZ cooperates with small RNAs (sRNAs) GlmY and GlmZ to regulate the glmS mRNA in Escherichia coli. Enzyme GlmS synthesizes glucosamine‐6‐phosphate (GlcN6P), initiating cell envelope biosynthesis. GlmZ activates glmS expression by base‐pairing. When GlcN6P is ample, GlmZ is bound by RapZ and degraded through ribonuclease recruitment. Upon GlcN6P depletion, the decoy sRNA GlmY accumulates through a previously unknown mechanism and sequesters RapZ, suppressing GlmZ decay. This circuit ensures GlcN6P homeostasis and thereby envelope integrity. In this work, we identify RapZ as GlcN6P receptor. GlcN6P‐free RapZ stimulates phosphorylation of the two‐component system QseE/QseF by interaction, which in turn activates glmY expression. Elevated GlmY levels sequester RapZ into stable complexes, which prevents GlmZ decay, promoting glmS expression. Binding of GlmY also prevents RapZ from activating QseE/QseF, generating a negative feedback loop limiting the response. When GlcN6P is replenished, GlmY is released from RapZ and rapidly degraded. We reveal a multifunctional sRNA‐binding protein that dynamically engages into higher‐order complexes for metabolite signaling.
Collapse
Affiliation(s)
- Muna A Khan
- Department of Microbiology, Immunobiology and Genetics, Max Perutz Labs, Vienna Biocenter (VBC), University of Vienna, Vienna, Austria
| | - Svetlana Durica-Mitic
- Department of Microbiology, Immunobiology and Genetics, Max Perutz Labs, Vienna Biocenter (VBC), University of Vienna, Vienna, Austria
| | - Yvonne Göpel
- Department of Microbiology, Immunobiology and Genetics, Max Perutz Labs, Vienna Biocenter (VBC), University of Vienna, Vienna, Austria
| | - Ralf Heermann
- Microbiology and Wine Research, Institute for Molecular Physiology, Johannes Gutenberg-University Mainz, Mainz, Germany
| | - Boris Görke
- Department of Microbiology, Immunobiology and Genetics, Max Perutz Labs, Vienna Biocenter (VBC), University of Vienna, Vienna, Austria
| |
Collapse
|
10
|
Wang L, Sun Z, Su C, Wang Y, Yan Q, Chen J, Ott T, Li X. A GmNINa-miR172c-NNC1 Regulatory Network Coordinates the Nodulation and Autoregulation of Nodulation Pathways in Soybean. Mol Plant 2019; 12:1211-1226. [PMID: 31201867 DOI: 10.1016/j.molp.2019.06.002] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2018] [Revised: 06/02/2019] [Accepted: 06/04/2019] [Indexed: 05/25/2023]
Abstract
Symbiotic root nodules are root lateral organs of plants in which nitrogen-fixing bacteria (rhizobia) convert atmospheric nitrogen to ammonia. The formation and number of nodules in legumes are precisely controlled by a rhizobia-induced signal cascade and host-controlled autoregulation of nodulation (AON). However, how these pathways are integrated and their underlying mechanisms are unclear. Here, we report that microRNA172c (miR172c) activates soybean (Glycine max) Rhizobia-Induced CLE1 (GmRIC1) and GmRIC2 by removing the transcriptional repression of these genes by Nodule Number Control 1 (NNC1), leading to the activation of the AON pathway. NNC1 interacts with GmNINa, the soybean ortholog of Lotus NODULE INCEPTION (NIN), and hampers its transcriptional activation of GmRIC1 and GmRIC2. Importantly, GmNINa acts as a transcriptional activator of miR172c. Intriguingly, NNC1 can transcriptionally repress miR172c expression, adding a negative feedback loop into the NNC1 regulatory network. Moreover, GmNINa interacts with NNC1 and can relieve the NNC1-mediated repression of miR172c transcription. Thus, the GmNINa-miR172c-NNC1 network is a master switch that coordinately regulates and optimizes NF and AON signaling, supporting the balance between nodulation and AON in soybean.
Collapse
Affiliation(s)
- Lixiang Wang
- State Key Laboratory of Agricultural Microbiology, College of Plant Science and Technology, Huazhong Agricultural University, No. 1 Shizishan Road, Hongshan District, Wuhan, Hubei 430070, P.R. China; College of Biological Science and Engineering, Panzhihua University, No. 10 Airport Road, Eastern District, Panzhihua, Sichuan, China
| | - Zhengxi Sun
- State Key Laboratory of Agricultural Microbiology, College of Plant Science and Technology, Huazhong Agricultural University, No. 1 Shizishan Road, Hongshan District, Wuhan, Hubei 430070, P.R. China
| | - Chao Su
- State Key Laboratory of Agricultural Microbiology, College of Plant Science and Technology, Huazhong Agricultural University, No. 1 Shizishan Road, Hongshan District, Wuhan, Hubei 430070, P.R. China; University of Freiburg, Faculty of Biology, University of Freiburg, Schänzlestrasse 1, 79104 Freiburg, Germany
| | - Yongliang Wang
- State Key Laboratory of Agricultural Microbiology, College of Plant Science and Technology, Huazhong Agricultural University, No. 1 Shizishan Road, Hongshan District, Wuhan, Hubei 430070, P.R. China
| | - Qiqi Yan
- State Key Laboratory of Agricultural Microbiology, College of Plant Science and Technology, Huazhong Agricultural University, No. 1 Shizishan Road, Hongshan District, Wuhan, Hubei 430070, P.R. China
| | - Jiahuan Chen
- State Key Laboratory of Agricultural Microbiology, College of Plant Science and Technology, Huazhong Agricultural University, No. 1 Shizishan Road, Hongshan District, Wuhan, Hubei 430070, P.R. China
| | - Thomas Ott
- University of Freiburg, Faculty of Biology, University of Freiburg, Schänzlestrasse 1, 79104 Freiburg, Germany; CIBSS - Centre for Integrative Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
| | - Xia Li
- State Key Laboratory of Agricultural Microbiology, College of Plant Science and Technology, Huazhong Agricultural University, No. 1 Shizishan Road, Hongshan District, Wuhan, Hubei 430070, P.R. China.
| |
Collapse
|
11
|
Xu Z, Zhang H, Zhang X, Jiang H, Liu C, Wu F, Qian L, Hao B, Czajkowsky DM, Guo S, Xu Z, Bi L, Wang S, Li H, Tan M, Yan W, Feng L, Hou J, Tao SC. Interplay between the bacterial protein deacetylase CobB and the second messenger c-di-GMP. EMBO J 2019; 38:e100948. [PMID: 31418899 DOI: 10.15252/embj.2018100948] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 07/05/2019] [Accepted: 07/18/2019] [Indexed: 12/15/2022] Open
Abstract
As a ubiquitous bacterial secondary messenger, c-di-GMP plays key regulatory roles in processes such as bacterial motility and transcription regulation. CobB is the Sir2 family protein deacetylase that controls energy metabolism, chemotaxis, and DNA supercoiling in many bacteria. Using an Escherichia coli proteome microarray, we found that c-di-GMP strongly binds to CobB. Further, protein deacetylation assays showed that c-di-GMP inhibits the activity of CobB and thereby modulates the biogenesis of acetyl-CoA. Interestingly, we also found that one of the key enzymes directly involved in c-di-GMP production, DgcZ, is a substrate of CobB. Deacetylation of DgcZ by CobB enhances its activity and thus the production of c-di-GMP. Our work establishes a novel negative feedback loop linking c-di-GMP biogenesis and CobB-mediated protein deacetylation.
Collapse
Affiliation(s)
- Zhaowei Xu
- Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai, China
| | - Hainan Zhang
- Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai, China
| | - Xingrun Zhang
- MOE Key Laboratory of Protein Sciences, Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China.,Department of Basic Medical Sciences, School of Medicine, Tsinghua University, Beijing, China
| | - Hewei Jiang
- Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai, China
| | - Chengxi Liu
- Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai, China
| | - Fanlin Wu
- Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai, China
| | - Lili Qian
- The Chemical Proteomics Center and State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Bingbing Hao
- The Chemical Proteomics Center and State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Daniel M Czajkowsky
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Shujuan Guo
- Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai, China
| | - Zhijing Xu
- College of Life Sciences, Shanghai Normal University, Shanghai, China
| | - Lijun Bi
- National Key Laboratory of Biomacromolecules, Key Laboratory of Non-Coding RNA and Key Laboratory of Protein and Peptide Pharmaceuticals, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.,School of Stomatology and Medicine, Foshan University, Foshan, China
| | - Shihua Wang
- School of Life Science, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Haitao Li
- MOE Key Laboratory of Protein Sciences, Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China.,Department of Basic Medical Sciences, School of Medicine, Tsinghua University, Beijing, China
| | - Minjia Tan
- The Chemical Proteomics Center and State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Wei Yan
- Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai, China
| | - Lei Feng
- Instrumental Analysis Center, Shanghai Jiao Tong University, Shanghai, China
| | - Jingli Hou
- Instrumental Analysis Center, Shanghai Jiao Tong University, Shanghai, China
| | - Sheng-Ce Tao
- Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai, China.,School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China.,State Key Laboratory of Oncogenes and Related Genes, Shanghai, China
| |
Collapse
|
12
|
Szybowska P, Kostas M, Wesche J, Wiedlocha A, Haugsten EM. Cancer Mutations in FGFR2 Prevent a Negative Feedback Loop Mediated by the ERK1/2 Pathway. Cells 2019; 8:cells8060518. [PMID: 31146385 PMCID: PMC6627556 DOI: 10.3390/cells8060518] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 05/24/2019] [Accepted: 05/28/2019] [Indexed: 01/21/2023] Open
Abstract
Tight regulation of signaling from receptor tyrosine kinases is required for normal cellular functions and uncontrolled signaling can lead to cancer. Fibroblast growth factor receptor 2 (FGFR2) is a receptor tyrosine kinase that induces proliferation and migration. Deregulation of FGFR2 contributes to tumor progression and activating mutations in FGFR2 are found in several types of cancer. Here, we identified a negative feedback loop regulating FGFR2 signaling. FGFR2 stimulates the Ras/MAPK signaling pathway consisting of Ras-Raf-MEK1/2-ERK1/2. Inhibition of this pathway using a MEK1/2 inhibitor increased FGFR2 signaling. The putative ERK1/2 phosphorylation site at serine 780 (S780) in FGFR2 corresponds to serine 777 in FGFR1 which is directly phosphorylated by ERK1/2. Substitution of S780 in FGFR2 to an alanine also increased signaling. Truncated forms of FGFR2 lacking the C-terminal tail, including S780, have been identified in cancer and S780 has been found mutated to leucine in bladder cancer. Substituting S780 in FGFR2 with leucine increased FGFR2 signaling. Importantly, cells expressing these mutated versions of S780 migrated faster than cells expressing wild-type FGFR2. Thus, ERK1/2-mediated phosphorylation of S780 in FGFR2 constitutes a negative feedback loop and inactivation of this feedback loop in cancer cells causes hyperactivation of FGFR2 signaling, which may result in increased invasive properties.
Collapse
Affiliation(s)
- Patrycja Szybowska
- Department of Molecular Cell Biology, Institute for Cancer Research, The Norwegian Radium Hospital, Oslo University Hospital, Montebello, 0379 Oslo, Norway.
- Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Montebello, 0379 Oslo, Norway.
| | - Michal Kostas
- Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Montebello, 0379 Oslo, Norway.
- Department of Tumor Biology, Institute for Cancer Research, The Norwegian Radium Hospital, Oslo University Hospital, Montebello, 0379 Oslo, Norway.
| | - Jørgen Wesche
- Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Montebello, 0379 Oslo, Norway.
- Department of Tumor Biology, Institute for Cancer Research, The Norwegian Radium Hospital, Oslo University Hospital, Montebello, 0379 Oslo, Norway.
| | - Antoni Wiedlocha
- Department of Molecular Cell Biology, Institute for Cancer Research, The Norwegian Radium Hospital, Oslo University Hospital, Montebello, 0379 Oslo, Norway.
- Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Montebello, 0379 Oslo, Norway.
- Military Institute of Hygiene and Epidemiology, 01-163 Warsaw, Poland.
| | - Ellen Margrethe Haugsten
- Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Montebello, 0379 Oslo, Norway.
- Department of Tumor Biology, Institute for Cancer Research, The Norwegian Radium Hospital, Oslo University Hospital, Montebello, 0379 Oslo, Norway.
| |
Collapse
|
13
|
Chen L, Liu YC, Zheng YY, Xu J, Zhang Y, Liu WL, Li ZY, Huang GD, Li WP. Furanodienone overcomes temozolomide resistance in glioblastoma through the downregulation of CSPG4-Akt-ERK signalling by inhibiting EGR1-dependent transcription. Phytother Res 2019; 33:1736-1747. [PMID: 31006910 DOI: 10.1002/ptr.6363] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 01/31/2019] [Accepted: 03/16/2019] [Indexed: 12/15/2022]
Abstract
Glioblastoma multiforme (GBM) is a highly aggressive type of brain tumour. Patients with GBM respond poorly to chemotherapy and have poor survival outcomes. Neuron-glial antigen 2 (NG2), also known as chondroitin sulphate proteoglycan 4 (CSPG4), has been shown to contribute to critical processes, such as cell survival, proliferation, and chemotherapy resistance, during glioma progression. In this study, we found that furanodienone (FUR), a diene-type sesquiterpene isolated from the rhizomes of Rhizoma curcumae, exhibited a potential cytotoxic effect on temozolomide (TMZ)-resistant GBM cells in vitro by inhibiting CSPG4 and related signalling pathways. Studies investigating the mechanism demonstrated that FUR suppressed CSPG4-Akt-ERK signalling, inflammatory responses, and cytokine levels but activated caspase-dependent pathways and mitochondrial dysfunction. Furthermore, an immunofluorescence assay and a dual-luciferase reporter assay revealed that inhibition of EGR1-mediated transcription might have contributed to the FUR-dependent blockade of CSPG4 signalling and glioma cell survival. These results established a link between FUR-induced CSPG4 inhibition and the suppression of EGR1-dependent transcription. Attenuation of ERK1/2 and cytokine signalling might have generated the EGR1-dependent negative feedback loop of the CSPG4 pathway during FUR-induced apoptosis. These findings suggested that FUR could be a therapeutic candidate for the treatment of malignant glioma via targeting CSPG4 signalling.
Collapse
Affiliation(s)
- Lei Chen
- Department of Neurosurgery, Shenzhen Key Laboratory of Neurosurgery, the First Affiliated Hospital of Shenzhen University, Shenzhen Second People's Hospital, 3002# Sungang Road, Futian District, Shenzhen, 518035, China
| | - Yue-Cheng Liu
- Department of Neurosurgery, Shenzhen Key Laboratory of Neurosurgery, the First Affiliated Hospital of Shenzhen University, Shenzhen Second People's Hospital, 3002# Sungang Road, Futian District, Shenzhen, 518035, China
| | - Yue-Yang Zheng
- Department of Neurosurgery, Shenzhen Key Laboratory of Neurosurgery, the First Affiliated Hospital of Shenzhen University, Shenzhen Second People's Hospital, 3002# Sungang Road, Futian District, Shenzhen, 518035, China
| | - Ji Xu
- Department of Neurosurgery, Shenzhen Key Laboratory of Neurosurgery, the First Affiliated Hospital of Shenzhen University, Shenzhen Second People's Hospital, 3002# Sungang Road, Futian District, Shenzhen, 518035, China
| | - Yuan Zhang
- Department of Neurosurgery, Shenzhen Key Laboratory of Neurosurgery, the First Affiliated Hospital of Shenzhen University, Shenzhen Second People's Hospital, 3002# Sungang Road, Futian District, Shenzhen, 518035, China
| | - Wen-Lan Liu
- Department of Neurosurgery, Shenzhen Key Laboratory of Neurosurgery, the First Affiliated Hospital of Shenzhen University, Shenzhen Second People's Hospital, 3002# Sungang Road, Futian District, Shenzhen, 518035, China
| | - Zong-Yang Li
- Department of Neurosurgery, Shenzhen Key Laboratory of Neurosurgery, the First Affiliated Hospital of Shenzhen University, Shenzhen Second People's Hospital, 3002# Sungang Road, Futian District, Shenzhen, 518035, China
| | - Guo-Dong Huang
- Department of Neurosurgery, Shenzhen Key Laboratory of Neurosurgery, the First Affiliated Hospital of Shenzhen University, Shenzhen Second People's Hospital, 3002# Sungang Road, Futian District, Shenzhen, 518035, China
| | - Wei-Ping Li
- Department of Neurosurgery, Shenzhen Key Laboratory of Neurosurgery, the First Affiliated Hospital of Shenzhen University, Shenzhen Second People's Hospital, 3002# Sungang Road, Futian District, Shenzhen, 518035, China
| |
Collapse
|
14
|
Maik-Rachline G, Hacohen-Lev-Ran A, Seger R. Nuclear ERK: Mechanism of Translocation, Substrates, and Role in Cancer. Int J Mol Sci 2019; 20:ijms20051194. [PMID: 30857244 PMCID: PMC6429060 DOI: 10.3390/ijms20051194] [Citation(s) in RCA: 107] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 03/03/2019] [Accepted: 03/04/2019] [Indexed: 12/15/2022] Open
Abstract
The extracellular signal-regulated kinases 1/2 (ERK) are central signaling components that regulate stimulated cellular processes such as proliferation and differentiation. When dysregulated, these kinases participate in the induction and maintenance of various pathologies, primarily cancer. While ERK is localized in the cytoplasm of resting cells, many of its substrates are nuclear, and indeed, extracellular stimulation induces a rapid and robust nuclear translocation of ERK. Similarly to other signaling components that shuttle to the nucleus upon stimulation, ERK does not use the canonical importinα/β mechanism of nuclear translocation. Rather, it has its own unique nuclear translocation signal (NTS) that interacts with importin7 to allow stimulated shuttling via the nuclear pores. Prevention of the nuclear translocation inhibits proliferation of B-Raf- and N/K-Ras-transformed cancers. This effect is distinct from the one achieved by catalytic Raf and MEK inhibitors used clinically, as cells treated with the translocation inhibitors develop resistance much more slowly. In this review, we describe the mechanism of ERK translocation, present all its nuclear substrates, discuss its role in cancer and compare its translocation to the translocation of other signaling components. We also present proof of principle data for the use of nuclear ERK translocation as an anti-cancer target. It is likely that the prevention of nuclear ERK translocation will eventually serve as a way to combat Ras and Raf transformed cancers with less side-effects than the currently used drugs.
Collapse
Affiliation(s)
- Galia Maik-Rachline
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot 7610001, Israel.
| | - Avital Hacohen-Lev-Ran
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot 7610001, Israel.
| | - Rony Seger
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot 7610001, Israel.
| |
Collapse
|
15
|
Zhou H, Lin-Wang K, Wang F, Espley RV, Ren F, Zhao J, Ogutu C, He H, Jiang Q, Allan AC, Han Y. Activator-type R2R3-MYB genes induce a repressor-type R2R3-MYB gene to balance anthocyanin and proanthocyanidin accumulation. New Phytol 2019; 221:1919-1934. [PMID: 30222199 DOI: 10.1111/nph.15486] [Citation(s) in RCA: 134] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Accepted: 09/12/2018] [Indexed: 05/22/2023]
Abstract
Anthocyanin and proanthocyanidin (PA) accumulation is regulated by both myeloblastosis (MYB) activators and repressors, but little information is available on hierarchical interactions between the positive and negative regulators. Here, we report on a R2R3-MYB repressor in peach, designated PpMYB18, which acts as a negative regulator of anthocyanin and PA accumulation. PpMYB18 can be activated by both anthocyanin- and PA-related MYB activators, and is expressed both at fruit ripening and juvenile stages when anthocyanins or PAs, respectively, are being synthesized. The PpMYB18 protein competes with MYB activators for binding to basic Helix Loop Helixes (bHLHs), which develops a fine-tuning regulatory loop to balance PA and anthocyanin accumulation. In addition, the bHLH binding motif in the R3 domain and the C1 and C2 repression motifs in the C-terminus of PpMYB18 both confer repressive activity of PpMYB18. Our study also demonstrates a modifying negative feedback loop, which prevents cells from excess accumulation of anthocyanin and PAs, and serves as a model for balancing secondary metabolite accumulation at the transcriptional level.
Collapse
Affiliation(s)
- Hui Zhou
- Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden of the Chinese Academy of Sciences, Wuhan, 430074, China
- Institute of Horticulture, Anhui Academy of Agricultural Sciences, Hefei, 230031, China
| | - Kui Lin-Wang
- The New Zealand Institute for Plant & Food Research Ltd, Mt Albert Research Centre, Private Bag, Auckland, 92169, New Zealand
| | - Furong Wang
- Institute of Fruit Tree and Tea, Hubei Academy of Agricultural Sciences, Wuhan, 430209, China
| | - Richard V Espley
- The New Zealand Institute for Plant & Food Research Ltd, Mt Albert Research Centre, Private Bag, Auckland, 92169, New Zealand
| | - Fei Ren
- Institute of Forestry and Pomology, Beijing Academy of Agriculture and Forestry Sciences, Beijing, 100097, China
| | - Jianbo Zhao
- Institute of Forestry and Pomology, Beijing Academy of Agriculture and Forestry Sciences, Beijing, 100097, China
| | - Collins Ogutu
- Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden of the Chinese Academy of Sciences, Wuhan, 430074, China
- Sino-African Joint Research Center, Chinese Academy of Sciences, Wuhan, 430074, China
| | - Huaping He
- Institute of Fruit Tree and Tea, Hubei Academy of Agricultural Sciences, Wuhan, 430209, China
| | - Quan Jiang
- Institute of Forestry and Pomology, Beijing Academy of Agriculture and Forestry Sciences, Beijing, 100097, China
| | - Andrew C Allan
- The New Zealand Institute for Plant & Food Research Ltd, Mt Albert Research Centre, Private Bag, Auckland, 92169, New Zealand
- School of Biological Sciences, University of Auckland, Auckland, 1020, New Zealand
| | - Yuepeng Han
- Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden of the Chinese Academy of Sciences, Wuhan, 430074, China
- Sino-African Joint Research Center, Chinese Academy of Sciences, Wuhan, 430074, China
- College of Horticulture Science and Engineering, Shandong Agricultural University, Tai-An, 271018, China
| |
Collapse
|
16
|
Liu Y, Zhang X, Zhou S, Shi J, Xu Y, He J, Lin F, Wei A, Zhou L, Chen Z. Knockdown of Golgi phosphoprotein 73 blocks the trafficking of matrix metalloproteinase-2 in hepatocellular carcinoma cells and inhibits cell invasion. J Cell Mol Med 2019; 23:2399-2409. [PMID: 30677226 PMCID: PMC6433683 DOI: 10.1111/jcmm.14055] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 10/13/2018] [Accepted: 11/07/2018] [Indexed: 12/12/2022] Open
Abstract
Golgi phosphoprotein 73 (GP73) has been regarded as a novel serum biomarker for the diagnosis of hepatocellular carcinoma (HCC) in recent years. It has been reported that the upregulation of GP73 may promote the carcinogenesis and metastasis of HCC; however, the mechanisms remain poorly understood. In this study, GP73 correlates positively with matrix metalloproteinase‐2 (MMP‐2) in HCC‐related cells and tissues. Further studies indicate that the knockdown of GP73 blocks MMP‐2 trafficking and secretion, resulting in cell invasion inhibition. Additionally, the knockdown of GP73 induces the accumulation of intracellular MMP‐2, which inhibits the phosphorylation of Src at Y416 and triggers the inhibition of SAPK/JNK and p53‐p21 signalling pathways through a negative feedback loop. Finally, the transactivation of MMP2 was inhibited by the reduction in E2F1. This study reveals that GP73 plays functional roles in the trafficking and equilibrium of epithelial‐mesenchymal transition (EMT)‐related secretory proteins and that GP73 serves as a new potential target for combating the metastasis of HCC.
Collapse
Affiliation(s)
- Yiming Liu
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Disease, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Department of Biochemistry and Molecular Biology, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiaodi Zhang
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Disease, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Department of Biochemistry and Molecular Biology, Zhejiang University School of Medicine, Hangzhou, China
| | - Sining Zhou
- Department of Biochemistry and Molecular Biology, Zhejiang University School of Medicine, Hangzhou, China
| | - Jieyao Shi
- Department of Biochemistry and Molecular Biology, Zhejiang University School of Medicine, Hangzhou, China
| | - Yun Xu
- Department of Pathology and Pathophysiology Program in Molecular Cell Biology, Zhejiang University School of Medicine, Hangzhou, China
| | - Jia He
- Institute of Immunology, Zhejiang University School of Medicine, Hangzhou, China
| | - Feng Lin
- Institute of Immunology, Zhejiang University School of Medicine, Hangzhou, China
| | - Anbang Wei
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Disease, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Linfu Zhou
- Department of Biochemistry and Molecular Biology, Zhejiang University School of Medicine, Hangzhou, China.,Key Laboratory of Clinical In Vitro Diagnostic Techniques of Zhejiang Province, Department of Clinical Laboratory, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Zhi Chen
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Disease, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| |
Collapse
|
17
|
Zhang ZB, Wang QY, Ke YX, Liu SY, Ju JQ, Lim WA, Tang C, Wei P. Design of Tunable Oscillatory Dynamics in a Synthetic NF-κB Signaling Circuit. Cell Syst 2017; 5:460-470.e5. [PMID: 29102361 DOI: 10.1016/j.cels.2017.09.016] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 07/18/2017] [Accepted: 09/25/2017] [Indexed: 12/11/2022]
Abstract
Although oscillatory circuits are prevalent in transcriptional regulation, it is unclear how a circuit's structure and the specific parameters that describe its components determine the shape of its oscillations. Here, we engineer a minimal, inducible human nuclear factor κB (NF-κB)-based system that is composed of NF-κB (RelA) and degradable inhibitor of NF-κB (IκBα), into the yeast, Saccharomyces cerevisiae. We define an oscillation's waveform quantitatively as a function of signal amplitude, rest time, rise time, and decay time; by systematically tuning RelA concentration, the strength of negative feedback, and the degradation rate of IκBα, we demonstrate that peak shape and frequency of oscillations can be controlled in vivo and predicted mathematically. In addition, we show that nested negative feedback loops can be employed to specifically tune the frequency of oscillations while leaving their peak shape unchanged. In total, this work establishes design principles that enable function-guided design of oscillatory signaling controllers in diverse synthetic biology applications.
Collapse
Affiliation(s)
- Zhi-Bo Zhang
- Center for Quantitative Biology and Peking-Tsinghua Joint Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China; The MOE Key Laboratory of Cell Proliferation and Differentiation, School of Life Sciences, Peking University, Beijing 100871, China
| | - Qiu-Yue Wang
- Center for Quantitative Biology and Peking-Tsinghua Joint Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Yu-Xi Ke
- School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Shi-Yu Liu
- The MOE Key Laboratory of Cell Proliferation and Differentiation, School of Life Sciences, Peking University, Beijing 100871, China
| | - Jian-Qi Ju
- Center for Quantitative Biology and Peking-Tsinghua Joint Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China; The MOE Key Laboratory of Cell Proliferation and Differentiation, School of Life Sciences, Peking University, Beijing 100871, China
| | - Wendell A Lim
- Center for Systems and Synthetic Biology, Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA; Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Chao Tang
- Center for Quantitative Biology and Peking-Tsinghua Joint Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Ping Wei
- Center for Quantitative Biology and Peking-Tsinghua Joint Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China; The MOE Key Laboratory of Cell Proliferation and Differentiation, School of Life Sciences, Peking University, Beijing 100871, China.
| |
Collapse
|
18
|
Zhang C, Liu J, Tan C, Yue X, Zhao Y, Peng J, Wang X, Laddha SV, Chan CS, Zheng S, Hu W, Feng Z. microRNA-1827 represses MDM2 to positively regulate tumor suppressor p53 and suppress tumorigenesis. Oncotarget 2016; 7:8783-96. [PMID: 26840028 DOI: 10.18632/oncotarget.7088] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Accepted: 01/15/2016] [Indexed: 12/14/2022] Open
Abstract
The tumor suppressor p53 plays a central role in tumor prevention. The E3 ubiquitin ligase MDM2 is the most critical negative regulator of p53, which binds to p53 and degrades p53 through ubiquitation. MDM2 itself is a transcriptional target of p53, and therefore, MDM2 forms a negative feedback loop with p53 to tightly regulate p53 levels and function. microRNAs (miRNAs) play a key role in regulation of gene expression. miRNA dysregulation plays an important role in tumorigenesis. In this study, we found that miRNA miR-1827 is a novel miRNA that targets MDM2 through binding to the 3′-UTR of MDM2 mRNA. miR-1827 negatively regulates MDM2, which in turn increases p53 protein levels to increase transcriptional activity of p53 and enhance p53-mediated stress responses, including apoptosis and senescence. Overexpression of miR-1827 suppresses the growth of xenograft colorectal tumors, whereas the miR-1827 inhibitor promotes tumor growth in mice in a largely p53-dependent manner. miR-1827 is frequently down-regulated in human colorectal cancer. Decreased miR-1827 expression is associated with high MDM2 expression and poor prognosis in colorectal cancer. In summary, our results reveal that miR-1827 is a novel miRNA that regulates p53 through targeting MDM2, and highlight an important role and the underlying mechanism of miR-1827 in tumor suppression.
Collapse
|
19
|
Miao Y, Warner M, Gustafsson JÅ. Liver X receptor β: new player in the regulatory network of thyroid hormone and 'browning' of white fat. Adipocyte 2016; 5:238-42. [PMID: 27386163 DOI: 10.1080/21623945.2016.1142634] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Revised: 01/06/2016] [Accepted: 01/07/2016] [Indexed: 01/24/2023] Open
Abstract
The recent discovery of browning of white adipose tissue (WAT) has raised great research interest because of its significant potential in counteracting obesity and type II diabetes. However, the mechanisms underlying browning are still poorly understood. Liver X receptors (LXRs) are one class of nuclear receptors, which play a vital role in regulating cholesterol, triglyceride and glucose metabolism. Following our previous finding that LXRs serve as repressors of UCP1 in classic brown adipose tissue in female mice, we found that LXRs, especially LXRβ, also repress the browning process of subcutaneous adipose tissue (SAT) in male rodents fed a normal diet. Depletion of LXRs activated thyrotropin releasing hormone positive neurons in the paraventricular area of the hypothalamus, and thus stimulated secretion of thyroid-stimulating hormone from the pituitary. Consequently production of thyroid hormones in the thyroid gland and circulating thyroid hormone level were increased. Moreover, the activity of thyroid signaling in SAT was markedly increased. One unexpected finding of our study is that LXRs are indispensable in the thyroid hormone negative feedback loop at the level of the hypothalamus. LXRs maintain expression of thyroid receptors in the brain and when they are inactivated there is no negative feedback of thyroid hormone in the hypothalamus. Together, our findings have uncovered the basis of increased energy expenditure in male LXR knock-out mice and provided support for targeting LXRs in treatment of obesity.
Collapse
Affiliation(s)
- Yifei Miao
- Center for Nuclear Receptors and Cell Signaling, Department of Biology and Biochemistry, University of Houston, Houston, TX, USA
| | - Margaret Warner
- Center for Nuclear Receptors and Cell Signaling, Department of Biology and Biochemistry, University of Houston, Houston, TX, USA
| | - Jan-Åke Gustafsson
- Center for Nuclear Receptors and Cell Signaling, Department of Biology and Biochemistry, University of Houston, Houston, TX, USA
- Center for Medical Innovations, Department of Biosciences and Nutrition, Karolinska Institutet, Novum, Stockholm, Sweden
| |
Collapse
|
20
|
Abstract
In development, morphogenetic processes are strictly coordinated in time. Cells in a developing tissue would need mechanisms for time-keeping. One such time-keeping mechanism is to use oscillations of gene expression. Oscillatory gene expression can be generated by transcriptional/translational feedback loops, usually referred to as a genetic oscillator. In this review article, we discuss genetic oscillators in the presence of developmental processes such as cell division, cell movement and cell differentiation. We first introduce the gene regulatory network for generating a rhythm of gene expression. We then discuss how developmental processes influence genetic oscillators. Examples include vertebrate somitogenesis and neural progenitor cell differentiation, as well as the circadian clock for comparison. To understand the behaviors of genetic oscillators in development, it is necessary to consider both gene expression dynamics and cellular behaviors simultaneously. Theoretical modeling combined with live imaging at single-cell resolution will be a powerful tool to analyze genetic oscillators in development.
Collapse
Affiliation(s)
- Koichiro Uriu
- Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa, 920-1192, Japan
| |
Collapse
|
21
|
Vexler K, Cymerman MA, Berezin I, Fridman A, Golani L, Lasnoy M, Saul H, Shaul O. The Arabidopsis NMD Factor UPF3 Is Feedback-Regulated at Multiple Levels and Plays a Role in Plant Response to Salt Stress. Front Plant Sci 2016; 7:1376. [PMID: 27746786 PMCID: PMC5040709 DOI: 10.3389/fpls.2016.01376] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2016] [Accepted: 08/29/2016] [Indexed: 05/22/2023]
Abstract
Nonsense-mediated mRNA decay (NMD) is a eukaryotic RNA surveillance mechanism that degrades aberrant transcripts and controls the levels of many normal mRNAs. It was shown that balanced expression of the NMD factor UPF3 is essential for the maintenance of proper NMD homeostasis in Arabidopsis. UPF3 expression is controlled by a negative feedback loop that exposes UPF3 transcript to NMD. It was shown that the long 3' untranslated region (3' UTR) of UPF3 exposes its transcript to NMD. Long 3' UTRs that subject their transcripts to NMD were identified in several eukaryotic NMD factors. Interestingly, we show here that a construct that contains all the regulatory regions of the UPF3 gene except this long 3' UTR is also feedback-regulated by NMD. This indicates that UPF3 expression is feedback-regulated at multiple levels. UPF3 is constitutively expressed in different plant tissues, and its expression is equal in leaves of plants of different ages. This finding is in agreement with the possibility that UPF3 is ubiquitously operative in the Arabidopsis NMD pathway. Expression mediated by the regulatory regions of UPF3 is significantly induced by salt stress. We found that both a deficiency and a strong excess of UPF3 expression are detrimental to plant resistance to salt stress. This indicates that UPF3 plays a role in plant response to salt stress, and that balanced expression of the UPF3 gene is essential for coping with this stress.
Collapse
|
22
|
Abstract
Neutel & Thorne (Ecology Letters, 17:651-661, June 2014) provide an approximation for the leading eigenvalue of a food web community matrix involving coefficients of its characteristic polynomial. Though valuably incorporating three-way species interactions, two critical problems emerge when one considers the dimensions of the system, calling the approach's accuracy and precision into question.
Collapse
Affiliation(s)
- Matthew J Smith
- Department of Ecology & Evolution, University of Chicago, 1101 E 57th Street, Chicago, IL, 60302, USA
| | - Elizabeth Sander
- Department of Ecology & Evolution, University of Chicago, 1101 E 57th Street, Chicago, IL, 60302, USA
| | - György Barabás
- Department of Ecology & Evolution, University of Chicago, 1101 E 57th Street, Chicago, IL, 60302, USA
| | - Stefano Allesina
- Department of Ecology & Evolution, University of Chicago, 1101 E 57th Street, Chicago, IL, 60302, USA.,Computation Institute, University of Chicago, 5735 S Ellis Avenue, Chicago, IL, 60637, USA
| |
Collapse
|
23
|
Fernandez-Lopez R, de la Cruz F. Rebooting the genome: The role of negative feedback in horizontal gene transfer. Mob Genet Elements 2015; 4:1-6. [PMID: 26442172 DOI: 10.4161/2159256x.2014.988069] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 10/24/2014] [Accepted: 11/07/2014] [Indexed: 11/19/2022] Open
Abstract
Horizontal Gene Transfer (HGT) is one of the key mechanisms driving bacterial evolution. Conjugative plasmids are fundamental vehicles for HGT in bacteria, playing an essential role in the spread of antibiotic resistances. Although the classical view has stressed the instrumental role of these mobile genetic elements in the dissemination of antibiotic resistance genes, plasmids contain a rich physiology devoted to horizontal and vertical reproduction. This particular lifestyle imposes specific constrains and trade-offs on plasmid physiology, and plasmids have evolved dedicated circuits to balance the opposing demands of vertical and horizontal reproduction. Recent studies on the transcriptional networks of IncW plasmids and other incompatibility groups have unveiled common architectures in the regulatory networks of different plasmid groups. Comparative studies show that negative feedback loops (NFLs) with strong gains are preferred, opening the question of a possible convergent evolution dictated by certain adaptive properties of this particular network motif. System analysis of NFLs with strong feedback gains indicate that this architecture exhibits transient overshooting after horizontal gene transfer. Since plasmid burden is dependent on the expression of plasmid functions, transcriptional overshooting results in a transient increase of the burden immediately after conjugation. We discuss the possible implications of this phenomenon on plasmid propagation, and the regulatory networks that plasmids have evolved to counteract the detrimental side effects of transient overshooting.
Collapse
Affiliation(s)
- Raul Fernandez-Lopez
- Instituto de Biomedicina y Biotecnologia de Cantabria IBBTEC; Universidad de Cantabria / CSIC ; Santander, Spain
| | - Fernando de la Cruz
- Instituto de Biomedicina y Biotecnologia de Cantabria IBBTEC; Universidad de Cantabria / CSIC ; Santander, Spain
| |
Collapse
|
24
|
Abstract
To ensure proper function, the tumor suppressor p53 is tightly regulated through different post-translational modifications, particularly ubiquitination. Recently, TRIM32 was identified as a p53-regulated gene and an E3 ubiquitin ligase of p53. Thus, TRIM32 and p53 form a novel auto-regulatory negative feedback loop for p53 regulation in cells.
Collapse
Affiliation(s)
- Juan Liu
- Department of Radiation Oncology; Rutgers Cancer Institute of New Jersey; Rutgers, State University of New Jersey ; New Brunswick, NJ USA
| | - Yu Zhu
- Department of Radiation Oncology; Rutgers Cancer Institute of New Jersey; Rutgers, State University of New Jersey; New Brunswick, NJ USA; Department of Neurosurgery; First Affiliated Hospital; Zhejiang University School of Medicine; Hangzhou, China
| | - Wenwei Hu
- Department of Radiation Oncology; Rutgers Cancer Institute of New Jersey; Rutgers, State University of New Jersey ; New Brunswick, NJ USA
| | - Zhaohui Feng
- Department of Radiation Oncology; Rutgers Cancer Institute of New Jersey; Rutgers, State University of New Jersey ; New Brunswick, NJ USA
| |
Collapse
|
25
|
Abstract
The transforming growth factor-β (TGF-β) signal transduction pathway controls many cellular processes, including differentiation, proliferation and apoptosis. It plays a fundamental role during development and it is dysregulated in many diseases. The factors that control the dynamics of the pathway, however, are not fully elucidated yet and so far computational approaches have been very limited in capturing the distinct types of behaviour observed under different cellular backgrounds and conditions into a single-model description. Here, we develop a detailed computational model for TGF-β signalling that incorporates elements of previous models together with crosstalking between Smad1/5/8 and Smad2/3 channels through a negative feedback loop dependent on Smad7. The resulting model accurately reproduces the diverse behaviour of experimental datasets for human keratinocytes, bovine aortic endothelial cells and mouse mesenchymal cells, capturing the dynamics of activation and nucleocytoplasmic shuttling of both R-Smad channels. The analysis of the model dynamics and its system properties revealed Smad7-mediated crosstalking between Smad1/5/8 and Smad2/3 channels as a major determinant in shaping the distinct responses to single and multiple ligand stimulation for different cell types.
Collapse
Affiliation(s)
- Daniel Nicklas
- Modeling of Biological Networks Laboratory, Department of Biomedical Engineering, University of California, 451 East Health Sciences Drive, Davis, CA 95616, USA
| | | |
Collapse
|
26
|
Abstract
One of the key mechanisms that mediate renal autoregulation is the tubuloglomerular feedback (TGF) system, which is a negative feedback loop in the kidney that balances glomerular filtration with tubular reabsorptive capacity. Tubular fluid flow, NaCl concentration and other related variables are known to exhibit TGF-mediated oscillations. In this study, we used a mathematical model of the thick ascending limb (TAL) of a short loop of Henle of the rat kidney to study the effects of (i) spatially inhomogeneous TAL NaCl active transport rate, (ii) spatially inhomogeneous tubular radius and (iii) compliance of the tubular walls on TGF-mediated dynamics. A bifurcation analysis of the TGF model equations was performed by deriving a characteristic equation and finding its roots. Results of the bifurcation analysis were validated via numerical simulations of the full model equations. Model results suggest that a higher TAL NaCl active transport rate or a smaller TAL radius near the loop bend gives rise to stable oscillatory solutions at sufficiently high TGF gain values, even with zero TGF delay. In addition, when the TAL walls are assumed to be compliant, the TGF system exhibits a heightened tendency to oscillate, a result that is consistent with predictions of a previous modelling study.
Collapse
Affiliation(s)
- Hwayeon Ryu
- Department of Mathematics, Duke University, Durham, NC 27708-0320, USA
| | | |
Collapse
|
27
|
Gedaly R, Angulo P, Hundley J, Daily MF, Chen C, Koch A, Evers BM. PI-103 and sorafenib inhibit hepatocellular carcinoma cell proliferation by blocking Ras/Raf/MAPK and PI3K/AKT/mTOR pathways. Anticancer Res 2010; 30:4951-4958. [PMID: 21187475 PMCID: PMC3141822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
BACKGROUND Aberrant Ras/Raf/MAPK and PI3K/AKT/mTOR signaling pathways are found in hepatocellular carcinoma (HCC). This study reports how sorafenib (a multi-kinase inhibitor) and PI-103 (a dual PI3K/mTOR inhibitor) alone and in combination inhibit the proliferation of the HCC cell line, Huh7. MATERIALS AND METHODS Huh7 proliferation was assayed by 3H-thymidine incorporation and by MTT assay. Western blot was used to detect phosphorylation of the key enzymes in the Ras/Raf and PI3K pathways. RESULTS Sorafenib and PI-103, as single agents inhibited Huh7 proliferation and epidermal growth factor (EGF)-stimulated Huh7 proliferation in a dose-dependent fashion; the combination of sorafenib and PI-103 produced synergistic effects. EGF increased phosphorylation of MEK and ERK, key Ras/Raf downstream signaling proteins; this activation was inhibited by sorafenib. However, sorafenib as a single agent increased AKT(Ser473) and mTOR phosphorylation. EGF-stimulated activation of PI3K/AKT/mTOR pathway components was inhibited by PI-103. PI-103 is a potent inhibitor of AKT(Ser473) phosphorylation; in contrast, rapamycin stimulated AKT(Ser473) phosphorylation. It was found that PI-103, as a single agent, stimulated MEK and ERK phosphorylation. However, the combination of sorafenib and PI-103 caused inhibition of all the tested kinases in the Ras/Raf and PI3K pathways. CONCLUSION The combination of sorafenib and PI-103 can significantly inhibit EGF-stimulated Huh7 proliferation by blocking both Ras/Raf/MAPK and PI3K/AKT/mTOR pathways.
Collapse
Affiliation(s)
- Roberto Gedaly
- Department of Surgery, University of Kentucky, College of Medicine, Lexington, KY 40536, USA.
| | | | | | | | | | | | | |
Collapse
|
28
|
Tu KC, Long T, Svenningsen SL, Wingreen NS, Bassler BL. Negative feedback loops involving small regulatory RNAs precisely control the Vibrio harveyi quorum-sensing response. Mol Cell 2010; 37:567-79. [PMID: 20188674 PMCID: PMC2844700 DOI: 10.1016/j.molcel.2010.01.022] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2009] [Revised: 11/03/2009] [Accepted: 12/11/2009] [Indexed: 11/30/2022]
Abstract
Quorum-sensing (QS) bacteria assess population density through secretion and detection of molecules called autoinducers (AIs). We identify and characterize two Vibrio harveyi negative feedback loops that facilitate precise transitions between low-cell-density (LCD) and high-cell-density (HCD) states. The QS central regulator LuxO autorepresses its own transcription, and the Qrr small regulatory RNAs (sRNAs) posttranscriptionally repress luxO. Disrupting feedback increases the concentration of AIs required for cells to transit from LCD to HCD QS modes. Thus, the two cooperative negative feedback loops determine the point at which V. harveyi has reached a quorum and control the range of AIs over which the transition occurs. Negative feedback regulation also constrains the range of QS output by preventing sRNA levels from becoming too high and preventing luxO mRNA levels from reaching zero. We suggest that sRNA-mediated feedback regulation is a network design feature that permits fine-tuning of gene regulation and maintenance of homeostasis.
Collapse
Affiliation(s)
- Kimberly C. Tu
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544-1014, USA
| | - Tao Long
- Department of Physics, Princeton University, Princeton, NJ 08544-1014, USA
| | - Sine L. Svenningsen
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544-1014, USA
| | - Ned S. Wingreen
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544-1014, USA
| | - Bonnie L. Bassler
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544-1014, USA
- Howard Hughes Medical Institute, Princeton University, Princeton, NJ 08544-1014, USA
| |
Collapse
|