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Panta M, Kump AJ, Schwab KR, Ahmad SM. Assessing the Roles of Potential Notch Signaling Components in Instructive and Permissive Pathways with Two Drosophila Pericardial Reporters. Methods Mol Biol 2022; 2472:109-130. [PMID: 35674896 DOI: 10.1007/978-1-0716-2201-8_10] [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: 06/15/2023]
Abstract
The highly conserved Notch signaling pathway brings about the transcriptional activation of target genes via either instructive or permissive mechanisms that depend on the identity of the specific target gene. As additional components of the Notch signaling pathway are identified, assessing whether each of these components are utilized exclusively by one of these mechanisms (and if so, which), or by both, becomes increasingly important. Using RNA interference-mediated knockdowns of the Notch component to be tested, reporters for two Notch-activated pericardial genes in Drosophila melanogaster, immunohistochemistry, and fluorescence microscopy, we describe a method to determine the type of signaling mechanism-instructive, permissive, or both-to which a particular Notch pathway component contributes.
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Affiliation(s)
- Manoj Panta
- Department of Biology, Indiana State University, Terre Haute, IN, USA
- The Center for Genomic Advocacy, Indiana State University, Terre Haute, IN, USA
| | - Andrew J Kump
- Department of Biology, Indiana State University, Terre Haute, IN, USA
- The Center for Genomic Advocacy, Indiana State University, Terre Haute, IN, USA
- Rich and Robin Porter Cancer Research Center, Indiana State University, Terre Haute, IN, USA
| | - Kristopher R Schwab
- Department of Biology, Indiana State University, Terre Haute, IN, USA
- The Center for Genomic Advocacy, Indiana State University, Terre Haute, IN, USA
- Rich and Robin Porter Cancer Research Center, Indiana State University, Terre Haute, IN, USA
| | - Shaad M Ahmad
- Department of Biology, Indiana State University, Terre Haute, IN, USA.
- The Center for Genomic Advocacy, Indiana State University, Terre Haute, IN, USA.
- Rich and Robin Porter Cancer Research Center, Indiana State University, Terre Haute, IN, USA.
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Tögel M, Pass G, Paululat A. Wing Hearts in Four-Winged Ultrabithorax-mutant Flies-the role of Hox genes in wing heart specification. Genetics 2021; 220:6428543. [PMID: 34791231 DOI: 10.1093/genetics/iyab191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 10/18/2021] [Indexed: 11/14/2022] Open
Abstract
Wings are probably the most advanced evolutionary novelty in insects. The development of wings requires the activity of so-called wing hearts located in the scutellum of the thorax. Immediately after the imaginal ecdysis, these accessory circulatory organs remove haemolymph and apoptotic epidermal cells from the premature wing through their pumping action. This clearing process is essential for the formation of functional wing blades. Mutant Drosophila that lack intact wing hearts are flightless and display malformed wings. The embryonic wing heart progenitors originate from two adjacent parasegments corresponding to the later thoracic segments T2 and T3. However, the adult dipterian fly harbors only one pair of wing hearts and also only one pair of wings located in thoracic segment T2. Here we show, that the specification of wing heart progenitors depends on the regulatory activity of the Hox gene Ultrabithorax. Furthermore, we analysed the development of four wing hearts in the famous four-winged Ultrabithorax (Ubx) mutant, which was first discovered by Ed Lewis in the 1970s. In these flies, the third thoracic segment (T3) is transformed into a second thoracic segment (HT2). This results in a second pair of wings instead of the club-shaped halteres normally formed by T3. We show that a second pair of wild-type wing hearts is formed in the four-winged fly and that all wing hearts originate from the wild-type progenitor cells.
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Affiliation(s)
- Markus Tögel
- Department of Biology, University of Osnabrück, Zoology/Developmental Biology, Barbarastraße 11, D-49069, Osnabrück, Germany
| | - Günther Pass
- Department of Evolutionary Biology, University of Vienna, Althanstraße 14, A-1090 Vienna, Austria
| | - Achim Paululat
- Department of Biology, University of Osnabrück, Zoology/Developmental Biology, Barbarastraße 11, D-49069, Osnabrück, Germany
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3
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Watanabe LP, Riddle NC. Exercise-induced changes in climbing performance. ROYAL SOCIETY OPEN SCIENCE 2021; 8:211275. [PMID: 34804578 PMCID: PMC8580468 DOI: 10.1098/rsos.211275] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Accepted: 10/12/2021] [Indexed: 05/13/2023]
Abstract
Exercise is recommended to promote health and prevent a range of diseases. However, how exercise precipitates these benefits is unclear, nor do we understand why exercise responses differ so widely between individuals. We investigate how climbing ability in Drosophila melanogaster changes in response to an exercise treatment. We find extensive variation in baseline climbing ability and exercise-induced changes ranging from -13% to +20% in climbing ability. Climbing ability, and its exercise-induced change, is sex- and genotype-dependent. GWASs implicate 'cell-cell signalling' genes in the control of climbing ability. We also find that animal activity does not predict climbing ability and that the exercise-induced climbing ability change cannot be predicted from the activity level induced by the exercise treatment. These results provide promising new avenues for further research into the molecular pathways controlling climbing activity and illustrate the complexities involved in trying to predict individual responses to exercise.
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Affiliation(s)
- Louis P. Watanabe
- Department of Biology, The University of Alabama at Birmingham, CH464, 1720 2nd Ave South, Birmingham, AL 35294, US
| | - Nicole C. Riddle
- Department of Biology, The University of Alabama at Birmingham, CH464, 1720 2nd Ave South, Birmingham, AL 35294, US
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Kuang Y, Pyo A, Eafergan N, Cain B, Gutzwiller LM, Axelrod O, Gagliani EK, Weirauch MT, Kopan R, Kovall RA, Sprinzak D, Gebelein B. Enhancers with cooperative Notch binding sites are more resistant to regulation by the Hairless co-repressor. PLoS Genet 2021; 17:e1009039. [PMID: 34559800 PMCID: PMC8494340 DOI: 10.1371/journal.pgen.1009039] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 10/06/2021] [Accepted: 09/08/2021] [Indexed: 11/21/2022] Open
Abstract
Notch signaling controls many developmental processes by regulating gene expression. Notch-dependent enhancers recruit activation complexes consisting of the Notch intracellular domain, the Cbf/Su(H)/Lag1 (CSL) transcription factor (TF), and the Mastermind co-factor via two types of DNA sites: monomeric CSL sites and cooperative dimer sites called Su(H) paired sites (SPS). Intriguingly, the CSL TF can also bind co-repressors to negatively regulate transcription via these same sites. Here, we tested how synthetic enhancers with monomeric CSL sites versus dimeric SPSs bind Drosophila Su(H) complexes in vitro and mediate transcriptional outcomes in vivo. Our findings reveal that while the Su(H)/Hairless co-repressor complex similarly binds SPS and CSL sites in an additive manner, the Notch activation complex binds SPSs, but not CSL sites, in a cooperative manner. Moreover, transgenic reporters with SPSs mediate stronger, more consistent transcription and are more resistant to increased Hairless co-repressor expression compared to reporters with the same number of CSL sites. These findings support a model in which SPS containing enhancers preferentially recruit cooperative Notch activation complexes over Hairless repression complexes to ensure consistent target gene activation. Cell signaling provides a basic means of communication during development. Many signaling pathways, including the Notch pathway, convert extracellular signals into changes in gene expression via transcription factors that bind specific DNA sequences. Importantly, the Notch pathway transcription factor can either form activating complexes upon Notch activation to stimulate gene expression or repression complexes with co-repressors to inhibit gene expression. Prior studies showed that the Notch activation complex binds DNA as either an independent complex on monomer binding sites or as two cooperative complexes (dimer) on paired binding sites. In this study, we used synthetic biology to examine how these two types of DNA sites impact the binding of Notch activation versus repression complexes and the output of Notch target gene expression. Our studies reveal that unlike the Notch activation complex, the repression complex does not cooperatively bind dimer sites. Moreover, our findings support the model that the enhanced stability of the Notch activation complex on dimer sites makes target genes with dimer sites less sensitive to the repression complex than target genes with only monomer sites. Thus, our studies reveal how target genes with different binding sites differ in sensitivity to the ratio of Notch activation to repression complexes.
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Affiliation(s)
- Yi Kuang
- Graduate Program in Molecular and Developmental Biology, Cincinnati Children’s Hospital Research Foundation, Cincinnati, Ohio, United States of America
| | - Anna Pyo
- Department of Biomedical Engineering, University of Cincinnati, Cincinnati, Ohio, United States of America
| | - Natanel Eafergan
- School of Neurobiology, Biochemistry and Biophysics, George S. Wise Faculty of Life Science, Tel Aviv University, Tel Aviv, Israel
| | - Brittany Cain
- Department of Biomedical Engineering, University of Cincinnati, Cincinnati, Ohio, United States of America
| | - Lisa M. Gutzwiller
- Division of Developmental Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, United States of America
| | - Ofri Axelrod
- School of Neurobiology, Biochemistry and Biophysics, George S. Wise Faculty of Life Science, Tel Aviv University, Tel Aviv, Israel
| | - Ellen K. Gagliani
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - Matthew T. Weirauch
- Divisions of Biomedical Informatics and Developmental Biology, Center for Autoimmune Genomics and Etiology (CAGE), Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, United States of America
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - Raphael Kopan
- Division of Developmental Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, United States of America
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - Rhett A. Kovall
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - David Sprinzak
- School of Neurobiology, Biochemistry and Biophysics, George S. Wise Faculty of Life Science, Tel Aviv University, Tel Aviv, Israel
| | - Brian Gebelein
- Division of Developmental Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, United States of America
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
- * E-mail:
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The Spatiotemporal Expression of Notch1 and Numb and Their Functional Interaction during Cardiac Morphogenesis. Cells 2021; 10:cells10092192. [PMID: 34571841 PMCID: PMC8471136 DOI: 10.3390/cells10092192] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 08/18/2021] [Accepted: 08/21/2021] [Indexed: 12/13/2022] Open
Abstract
Numb family proteins (NFPs), including Numb and Numblike (Numbl), are commonly known for their role as cell fate determinants for multiple types of progenitor cells, mainly due to their function as Notch inhibitors. Previous studies have shown that myocardial NFP double knockout (MDKO) hearts display an up-regulated Notch activation and various defects in cardiac progenitor cell differentiation and cardiac morphogenesis. Whether enhanced Notch activation causes these defects in MDKO is not fully clear. To answer the question, we examined the spatiotemporal patterns of Notch1 expression, Notch activation, and Numb expression in the murine embryonic hearts using multiple approaches including RNAScope, and Numb and Notch reporter mouse lines. To further interrogate the interaction between NFPs and Notch signaling activation, we deleted both Notch1 or RBPJk alleles in the MDKO. We examined and compared the phenotypes of Notch1 knockout, NFPs double knockout, Notch1; Numb; Numbl and RBPJk; Numb; Numbl triple knockouts. Our study showed that Notch1 is expressed and activated in the myocardium at several stages, and Numb is enriched in the epicardium and did not show the asymmetric distribution in the myocardium. Cardiac-specific Notch1 deletion causes multiple structural defects and embryonic lethality. Notch1 or RBPJk deletion in MDKO did not rescue the structural defects in the MDKO but partially rescued the defects of cardiac progenitor cell differentiation, cardiomyocyte proliferation, and trabecular morphogenesis. Our study concludes that NFPs regulate progenitor cell differentiation, cardiomyocyte proliferation, and trabecular morphogenesis partially through Notch1 and play more roles than inhibiting Notch1 signaling during cardiac morphogenesis.
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Chen J, Cheng W, Li J, Wang Y, Chen J, Shen X, Su A, Gan D, Ke L, Liu G, Lin J, Li L, Bai X, Zhang P. Notch-1 and Notch-3 Mediate Hypoxia-Induced Activation of Synovial Fibroblasts in Rheumatoid Arthritis. Arthritis Rheumatol 2021; 73:1810-1819. [PMID: 33844448 DOI: 10.1002/art.41748] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 03/23/2021] [Indexed: 12/13/2022]
Abstract
OBJECTIVE To investigate the molecular mechanism of hypoxia-induced rheumatoid arthritis synovial fibroblast (RASF) activation via Notch-1 and Notch-3 signaling, and to evaluate its potential as a therapeutic target. METHODS Expression of Notch-1 intracellular domain (N1ICD), N3ICD, and hypoxia-inducible factor 1α (HIF-1α) was assessed by immunhistology in synovial tissue from patients with RA. RASFs were cultured under hypoxic conditions and normoxic conditions with or without small interfering RNAs (siRNAs), and N1ICD and N3ICD were overexpressed under normoxic conditions. Rats with collagen-induced arthritis (CIA) were administered LY411575 (inhibitor of N1ICD and N3ICD) for 15 days and 28 days, and its therapeutic efficacy was assessed by histologic and radiologic evaluation of the rat synovial tissue, and by analysis of inflammatory cytokine production in the serum of rats. RESULTS N1ICD, N3ICD, and HIF-1α were expressed abundantly in the synovial tissue of RA patients. HIF-1α was shown to directly regulate the expression of Notch-1 and Notch-3 genes under hypoxic conditions. Moreover, hypoxia-induced N1ICD and N3ICD expression in RASFs was blocked by HIF-1α siRNA. Notch-1 siRNA and Notch-3 siRNA inhibited hypoxia-induced RASF invasion and angiogenesis in vitro, whereas overexpression of N1ICD and N3ICD promoted these processes. In addition, Notch-1 was shown to regulate RASF migration and epithelial-mesenchymal transition under hypoxic conditions, whereas Notch-3 was shown to regulate the processes of anti-apoptosis and autophagy. Furthermore, in vivo studies in rats with CIA showed that the N1ICD and N3ICD inhibitor LY411575 had a therapeutic effect in terms of ameliorating the symptoms and severity of the disease. CONCLUSION This study identified a functional link between HIF-1α, Notch-1, and Notch-3 signaling in regulating activation of RASFs and the processes involved in the pathogenesis of RA.
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Affiliation(s)
- Jianhai Chen
- Center for Translational Medicine Research and Development, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, China and University of Chinese Academy of Sciences, Beijing, China
| | - Wenxiang Cheng
- Center for Translational Medicine Research and Development, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, China and University of Chinese Academy of Sciences, Beijing, China
| | - Jian Li
- Center for Translational Medicine Research and Development, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, China and University of Chinese Academy of Sciences, Beijing, China
| | - Yan Wang
- Center for Translational Medicine Research and Development, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, China and University of Chinese Academy of Sciences, Beijing, China
| | - Jingqin Chen
- Center for Translational Medicine Research and Development, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, China and University of Chinese Academy of Sciences, Beijing, China
| | - Xin Shen
- Center for Translational Medicine Research and Development, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, China and University of Chinese Academy of Sciences, Beijing, China
| | - Ailing Su
- Center for Translational Medicine Research and Development, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, China and University of Chinese Academy of Sciences, Beijing, China
| | - Donghao Gan
- Shandong University of Traditional Chinese Medicine, Jinan City, Jinan City, Shangdong, China
| | - Liqing Ke
- Center for Translational Medicine Research and Development, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, China and University of Chinese Academy of Sciences, Beijing, China
| | - Gang Liu
- Shenzhen Hospital, University of Chinese Academy of Sciences, Beijing, China
| | - Jietao Lin
- Center for Translational Medicine Research and Development, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, China and University of Chinese Academy of Sciences, Beijing, China
| | - Liang Li
- Institutes of Biomedicine and Biotechnology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, China
| | - Xueling Bai
- Center for Translational Medicine Research and Development, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, China and University of Chinese Academy of Sciences, Beijing, China
| | - Peng Zhang
- Center for Translational Medicine Research and Development, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, China and University of Chinese Academy of Sciences, Beijing, China
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Chen J, Li J, Chen J, Cheng W, Lin J, Ke L, Liu G, Bai X, Zhang P. Treatment of collagen-induced arthritis rat model by using Notch signalling inhibitor. J Orthop Translat 2021; 28:100-107. [PMID: 33816113 PMCID: PMC7995347 DOI: 10.1016/j.jot.2021.01.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 11/22/2020] [Accepted: 01/15/2021] [Indexed: 12/27/2022] Open
Abstract
Background The Notch signalling pathway has been reported to play a key role in rheumatoid arthritis (RA) development. Thus, inhibition of the activation of this signalling pathway may be a promising approach to the treatment of RA. In this study, the Notch signalling inhibitor LY411575, which can inhibit both Notch1 and Notch3, was used for the treatment of collagen-induced arthritis (CIA) rats. Methods Wistar rats were immunised with bovine type II collagen (CII) to establish rats CIA model. The inhibitory effects of LY411575 on Notch1 intracellular domain (N1ICD) and Notch3 intracellular domain (N3ICD) protein was verified by western blot (WB) in vitro. CIA rats were treated with different doses of LY411575 for 15 and 28 days, respectively. Methotrexate and sodium carboxymethyl cellulose (CMC-Na) were used as positive and negative (vehicle) control respectively. Destruction of the rat ankle joint and the bone loss on the periarticular side were evaluated by micro-computed tomography (Micro-CT). In addition, destruction of the ankle articular cartilage and the osteoclast numbers were determined by histology. Expression of N1ICD and N3ICD in the ankle joint was detected by immunohistochemistry. Results LY411575 could significantly inhibit the expression of N1ICD and N3ICD in vitro. Micro-CT test showed that the ankle joint destruction significantly improved after treatment with LY411575 (5 mg/kg and 10 mg/kg, respectively). The bone quality in the LY411575 (5 mg/kg and 10 mg/kg, respectively) groups were improved compared with the vehicle group. Histological analysis showed that LY411575 (5 mg/kg and 10 mg/kg, respectively) treatment reduced the severity of ankle joint inflammation in CIA rats (including ankle joint destruction, pannus formation, and cartilage damage) and reduced the expression of N1ICD and N3ICD in CIA rats ankle joints significantly. Conclusion The inhibitor of Notch signalling LY411575 is an effective treatment for CIA. The translational potential of this article Our study provides new evidence to support the potential clinical application of Notch signalling pathway inhibitor LY411575 as a drug candidate for the treatment of RA.
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Affiliation(s)
- Jianhai Chen
- Center for Translational Medicine Research and Development, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, 518055, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jian Li
- Center for Translational Medicine Research and Development, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, 518055, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jinqing Chen
- Research Laboratory for Biomedical Optics and Molecular Imaging, Shenzhen Key Laboratory for Molecular Imaging, Guangdong Provincial Key Laboratory of Biomedical Optical Imaging Technology, CAS Key Laboratory of Health Informatics, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Wenxiang Cheng
- Center for Translational Medicine Research and Development, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, 518055, China
| | - Jietao Lin
- Center for Translational Medicine Research and Development, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, 518055, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Liqing Ke
- Center for Translational Medicine Research and Development, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, 518055, China
| | - Gang Liu
- Shenzhen Hospital, University of Chinese Academy of Sciences, China
| | - Xueling Bai
- Center for Translational Medicine Research and Development, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, 518055, China
| | - Peng Zhang
- Center for Translational Medicine Research and Development, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, 518055, China.,University of Chinese Academy of Sciences, Beijing, 100049, China.,Shenzhen Engineering Research Center for Medical Bioactive Materials, China.,Shenzhen Hospital, University of Chinese Academy of Sciences, China
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Phosphatidic acid increases Notch signalling by affecting Sanpodo trafficking during Drosophila sensory organ development. Sci Rep 2020; 10:21731. [PMID: 33303974 PMCID: PMC7729928 DOI: 10.1038/s41598-020-78831-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 11/27/2020] [Indexed: 11/08/2022] Open
Abstract
Organ cell diversity depends on binary cell-fate decisions mediated by the Notch signalling pathway during development and tissue homeostasis. A clear example is the series of binary cell-fate decisions that take place during asymmetric cell divisions that give rise to the sensory organs of Drosophila melanogaster. The regulated trafficking of Sanpodo, a transmembrane protein that potentiates receptor activity, plays a pivotal role in this process. Membrane lipids can regulate many signalling pathways by affecting receptor and ligand trafficking. It remains unknown, however, whether phosphatidic acid regulates Notch-mediated binary cell-fate decisions during asymmetric cell divisions, and what are the cellular mechanisms involved. Here we show that increased phosphatidic acid derived from Phospholipase D leads to defects in binary cell-fate decisions that are compatible with ectopic Notch activation in precursor cells, where it is normally inactive. Null mutants of numb or the α-subunit of Adaptor Protein complex-2 enhance dominantly this phenotype while removing a copy of Notch or sanpodo suppresses it. In vivo analyses show that Sanpodo localization decreases at acidic compartments, associated with increased internalization of Notch. We propose that Phospholipase D-derived phosphatidic acid promotes ectopic Notch signalling by increasing receptor endocytosis and inhibiting Sanpodo trafficking towards acidic endosomes.
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Zmojdzian M, de Joussineau S, Da Ponte JP, Jagla K. Distinct subsets of Eve-positive pericardial cells stabilise cardiac outflow and contribute to Hox gene-triggered heart morphogenesis in Drosophila. Development 2018; 145:dev.158717. [PMID: 29247145 PMCID: PMC5825839 DOI: 10.1242/dev.158717] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Accepted: 12/11/2017] [Indexed: 11/20/2022]
Abstract
The Drosophila heart, composed of discrete subsets of cardioblasts and pericardial cells, undergoes Hox-triggered anterior-posterior morphogenesis, leading to a functional subdivision into heart proper and aorta, with its most anterior part forming a funnel-shaped cardiac outflow. Cardioblasts differentiate into Tin-positive 'working myocytes' and Svp-expressing ostial cells. However, developmental fates and functions of heart-associated pericardial cells remain elusive. Here, we show that the pericardial cells that express the transcription factor Even Skipped adopt distinct fates along the anterior-posterior axis. Among them, the most anterior Antp-Ubx-AbdA-negative cells form a novel cardiac outflow component we call the outflow hanging structure, whereas the Antp-expressing cells differentiate into wing heart precursors. Interestingly, Hox gene expression in the Even Skipped-positive cells not only underlies their antero-posterior diversification, but also influences heart morphogenesis in a non-cell-autonomous way. In brief, we identify a new cardiac outflow component derived from a subset of Even Skipped-expressing cells that stabilises the anterior heart tip, and demonstrate non-cell-autonomous effects of Hox gene expression in the Even Skipped-positive cells on heart morphogenesis.
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Affiliation(s)
- Monika Zmojdzian
- GReD - INSERM U1103, CNRS UMR6293, University of Clermont Auvergne, 63000 Clermont-Ferrand, France
| | - Svetlana de Joussineau
- GReD - INSERM U1103, CNRS UMR6293, University of Clermont Auvergne, 63000 Clermont-Ferrand, France
| | - Jean Philippe Da Ponte
- GReD - INSERM U1103, CNRS UMR6293, University of Clermont Auvergne, 63000 Clermont-Ferrand, France
| | - Krzysztof Jagla
- GReD - INSERM U1103, CNRS UMR6293, University of Clermont Auvergne, 63000 Clermont-Ferrand, France
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10
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Ahmad SM. Conserved signaling mechanisms in Drosophila heart development. Dev Dyn 2017; 246:641-656. [PMID: 28598558 DOI: 10.1002/dvdy.24530] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 04/06/2017] [Accepted: 05/08/2017] [Indexed: 12/24/2022] Open
Abstract
Signal transduction through multiple distinct pathways regulates and orchestrates the numerous biological processes comprising heart development. This review outlines the roles of the FGFR, EGFR, Wnt, BMP, Notch, Hedgehog, Slit/Robo, and other signaling pathways during four sequential phases of Drosophila cardiogenesis-mesoderm migration, cardiac mesoderm establishment, differentiation of the cardiac mesoderm into distinct cardiac cell types, and morphogenesis of the heart and its lumen based on the proper positioning and cell shape changes of these differentiated cardiac cells-and illustrates how these same cardiogenic roles are conserved in vertebrates. Mechanisms bringing about the regulation and combinatorial integration of these diverse signaling pathways in Drosophila are also described. This synopsis of our present state of knowledge of conserved signaling pathways in Drosophila cardiogenesis and the means by which it was acquired should facilitate our understanding of and investigations into related processes in vertebrates. Developmental Dynamics 246:641-656, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Shaad M Ahmad
- Department of Biology, Indiana State University, Terre Haute, Indiana.,The Center for Genomic Advocacy, Indiana State University, Terre Haute, Indiana
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Werner K, Donow C, Pandur P. Chip/Ldb1 interacts with Tailup/islet1 to regulate cardiac gene expression inDrosophila. Genesis 2017; 55. [DOI: 10.1002/dvg.23030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Revised: 03/09/2017] [Accepted: 03/10/2017] [Indexed: 11/11/2022]
Affiliation(s)
- Kathrin Werner
- Institut für Biochemie und Molekulare Biologie; Albert-Einstein-Allee 11; 89081 Ulm Germany
| | - Cornelia Donow
- Institut für Biochemie und Molekulare Biologie; Albert-Einstein-Allee 11; 89081 Ulm Germany
| | - Petra Pandur
- Institut für Biochemie und Molekulare Biologie; Albert-Einstein-Allee 11; 89081 Ulm Germany
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12
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XIE CHENGZHI, LU ZHENHUI, LIU GUOXING, FANG YU, LIU JIEFENG, HUANG ZHAO, WANG FUSHENG, WU XIAOLONG, LEI XIAOHUA, LI XIAOCHENG, ZHANG YUEMING, HU ZECHENG, QIAN KE, HU JIXIONG, HUANG SHENGFU, ZHONG DEWU, XU XUNDI. Numb downregulation suppresses cell growth and is associated with a poor prognosis of human hepatocellular carcinoma. Int J Mol Med 2015; 36:653-60. [PMID: 26165304 PMCID: PMC4533774 DOI: 10.3892/ijmm.2015.2279] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2015] [Accepted: 06/24/2015] [Indexed: 01/06/2023] Open
Abstract
Numb, an endocytic adaptor, is a known cell fate determinant that participates in asymmetric cell division. The present study aimed to explore the potential roles of Numb in hepatocarcinogenesis. Numb expression was investigated in hepatocellular carcinomas (HCC) with reverse transcription‑quantitative polymerase chain reaction and immunohistochemical examination; its association with the prognosis of HCC patients was analyzed. In addition, the effects of Numb deletion on proliferation of HCC cells and its relevant molecules were evaluated in Huh7 and HepG2 cells. Numb overexpression was observed in 62% of adjacent non‑tumor tissues and 46% of tumor tissues. Overexpression of Numb in HCC was associated with histological grade, portal vein invasion and the number of tumors (P=0.001, 0.022 and 0.034 respectively). Multivariate analysis revealed that Numb expression was an independent prognostic indicator of HCC patients. Methylation of the Numb promoter contributed to hepatocarcinogenesis. In vitro assays demonstrated that Numb silencing resulted in inhibition of cell proliferation, induction of apoptosis, downregulation of cyclin‑dependent protein kinase 4 (CDK4) and S‑phase kinase‑associated protein 2 (SKP2), and upregulation of Bcl‑2 homologous antagonist/killer (BAK) and cyclin‑dependent kinase inhibitor 1 (p21). The present study suggests that downregulation of Numb inhibits colony formation and cell proliferation, induces apoptosis of HCC cells and independently predicts the poor prognosis of HCC patients. Thus, Numb has a potential role in the development and progression of HCC.
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Affiliation(s)
- CHENGZHI XIE
- Division of Hepatobiliary-Pancreatic Surgery, Department of Surgery, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, P.R. China
- Department of General Surgery, The Second Affiliated Hospital, Hunan University of Chinese Medicine, Changsha, Hunan 410005, P.R. China
| | - ZHENHUI LU
- Department of Hepatobiliary Surgery, General Hospital of Ningxia Medical University, Yinchuan, Ningxia Hui Autonomous Region 750004, P.R. China
| | - GUOXING LIU
- Division of Hepatobiliary-Pancreatic Surgery, Department of Surgery, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, P.R. China
| | - YU FANG
- Division of Hepatobiliary-Pancreatic Surgery, Department of Surgery, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, P.R. China
| | - JIEFENG LIU
- Division of Hepatobiliary-Pancreatic Surgery, Department of Surgery, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, P.R. China
| | - ZHAO HUANG
- Division of Hepatobiliary-Pancreatic Surgery, Department of Surgery, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, P.R. China
| | - FUSHENG WANG
- Division of Hepatobiliary-Pancreatic Surgery, Department of Surgery, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, P.R. China
| | - XIAOLONG WU
- Division of Hepatobiliary-Pancreatic Surgery, Department of Surgery, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, P.R. China
| | - XIAOHUA LEI
- Division of Hepatobiliary-Pancreatic Surgery, Department of Surgery, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, P.R. China
| | - XIAOCHENG LI
- Division of Hepatobiliary-Pancreatic Surgery, Department of Surgery, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, P.R. China
| | - YUEMING ZHANG
- Division of Hepatobiliary-Pancreatic Surgery, Department of Surgery, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, P.R. China
| | - ZECHENG HU
- Division of Hepatobiliary-Pancreatic Surgery, Department of Surgery, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, P.R. China
| | - KE QIAN
- Division of Hepatobiliary-Pancreatic Surgery, Department of Surgery, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, P.R. China
| | - JIXIONG HU
- Division of Hepatobiliary-Pancreatic Surgery, Department of Surgery, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, P.R. China
| | - SHENGFU HUANG
- Division of Hepatobiliary-Pancreatic Surgery, Department of Surgery, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, P.R. China
| | - DEWU ZHONG
- Division of Hepatobiliary-Pancreatic Surgery, Department of Surgery, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, P.R. China
| | - XUNDI XU
- Division of Hepatobiliary-Pancreatic Surgery, Department of Surgery, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, P.R. China
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Dobi KC, Schulman VK, Baylies MK. Specification of the somatic musculature in Drosophila. WILEY INTERDISCIPLINARY REVIEWS. DEVELOPMENTAL BIOLOGY 2015; 4:357-75. [PMID: 25728002 PMCID: PMC4456285 DOI: 10.1002/wdev.182] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Revised: 01/16/2015] [Accepted: 02/04/2015] [Indexed: 11/09/2022]
Abstract
The somatic muscle system formed during Drosophila embryogenesis is required for larvae to hatch, feed, and crawl. This system is replaced in the pupa by a new adult muscle set, responsible for activities such as feeding, walking, and flight. Both the larval and adult muscle systems are comprised of distinct muscle fibers to serve these specific motor functions. In this way, the Drosophila musculature is a valuable model for patterning within a single tissue: while all muscle cells share properties such as the contractile apparatus, properties such as size, position, and number of nuclei are unique for a particular muscle. In the embryo, diversification of muscle fibers relies first on signaling cascades that pattern the mesoderm. Subsequently, the combinatorial expression of specific transcription factors leads muscle fibers to adopt particular sizes, shapes, and orientations. Adult muscle precursors (AMPs), set aside during embryonic development, proliferate during the larval phases and seed the formation of the abdominal, leg, and flight muscles in the adult fly. Adult muscle fibers may either be formed de novo from the fusion of the AMPs, or are created by the binding of AMPs to an existing larval muscle. While less is known about adult muscle specification compared to the larva, expression of specific transcription factors is also important for its diversification. Increasingly, the mechanisms required for the diversification of fly muscle have found parallels in vertebrate systems and mark Drosophila as a robust model system to examine questions about how diverse cell types are generated within an organism.
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Affiliation(s)
- Krista C. Dobi
- Program in Developmental Biology, Sloan Kettering Institute, New York, NY, USA
| | - Victoria K. Schulman
- Program in Developmental Biology, Sloan Kettering Institute, New York, NY, USA
- Cell and Developmental Biology, Weill Cornell Graduate School of Medical Sciences, Cornell University, New York, NY, USA
| | - Mary K. Baylies
- Program in Developmental Biology, Sloan Kettering Institute, New York, NY, USA
- Cell and Developmental Biology, Weill Cornell Graduate School of Medical Sciences, Cornell University, New York, NY, USA
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Wu M, Li J. Numb family proteins: novel players in cardiac morphogenesis and cardiac progenitor cell differentiation. Biomol Concepts 2015; 6:137-48. [PMID: 25883210 PMCID: PMC4589147 DOI: 10.1515/bmc-2015-0003] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Accepted: 03/16/2015] [Indexed: 11/15/2022] Open
Abstract
Vertebrate heart formation is a spatiotemporally regulated morphogenic process that initiates with bilaterally symmetric cardiac primordial cells migrating toward the midline to form a linear heart tube. The heart tube then elongates and undergoes a series of looping morphogenesis, followed by expansions of regions that are destined to become primitive heart chambers. During the cardiac morphogenesis, cells derived from the first heart field contribute to the primary heart tube, and cells from the secondary heart field, cardiac neural crest, and pro-epicardial organ are added to the heart tube in a precise spatiotemporal manner. The coordinated addition of these cells and the accompanying endocardial cushion morphogenesis yield the atrial, ventricular, and valvular septa, resulting in the formation of a four-chambered heart. Perturbation of progenitor cells' deployment and differentiation leads to a spectrum of congenital heart diseases. Two of the genes that were recently discovered to be involved in cardiac morphogenesis are Numb and Numblike. Numb, an intracellular adaptor protein, distinguishes sibling cell fates by its asymmetric distribution between the two daughter cells and its ability to inhibit Notch signaling. Numb regulates cardiac progenitor cell differentiation in Drosophila and controls heart tube laterality in Zebrafish. In mice, Numb and Numblike, the Numb family proteins (NFPs), function redundantly and have been shown to be essential for epicardial development, cardiac progenitor cell differentiation, outflow tract alignment, atrioventricular septum morphogenesis, myocardial trabeculation, and compaction. In this review, we will summarize the functions of NFPs in cardiac development and discuss potential mechanisms of NFPs in the regulation of cardiac development.
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Affiliation(s)
- M Wu
- Cardiovascular Science Center, Albany Medical College, Albany NY 12208
| | - J Li
- Cardiovascular Science Center, Albany Medical College, Albany NY 12208
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15
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Abstract
Many of the major discoveries in the fields of genetics and developmental biology have been made using the fruit fly, Drosophila melanogaster. With regard to heart development, the conserved network of core cardiac transcription factors that underlies cardiogenesis has been studied in great detail in the fly, and the importance of several signaling pathways that regulate heart morphogenesis, such as Slit/Robo, was first shown in the fly model. Recent technological advances have led to a large increase in the genomic data available from patients with congenital heart disease (CHD). This has highlighted a number of candidate genes and gene networks that are potentially involved in CHD. To validate genes and genetic interactions among candidate CHD-causing alleles and to better understand heart formation in general are major tasks. The specific limitations of the various cardiac model systems currently employed (mammalian and fish models) provide a niche for the fly model, despite its evolutionary distance to vertebrates and humans. Here, we review recent advances made using the Drosophila embryo that identify factors relevant for heart formation. These underline how this model organism still is invaluable for a better understanding of CHD.
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Rooney P, Connolly M, Gao W, McCormick J, Biniecka M, Sullivan O, Kirby B, Sweeney C, Molloy E, Markham T, Fearon U, Veale DJ. Notch-1 mediates endothelial cell activation and invasion in psoriasis. Exp Dermatol 2014; 23:113-8. [PMID: 24330353 DOI: 10.1111/exd.12306] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/11/2013] [Indexed: 01/20/2023]
Abstract
Notch receptor-ligand interactions are critical for cell proliferation, differentiation and survival; however, the role of Notch signalling in psoriasis remains to be elucidated. Serum amyloid A (A-SAA) is an acute-phase protein with cytokine-like properties, regulates cell survival pathways and is implicated in many inflammatory conditions. To examine the role of Notch-1 signalling in the pathogenesis of psoriasis, Notch-1, DLL-4, Jagged-1, Hrt-1/Hrt-2, A-SAA, Factor VIII and vascular endothelial growth factor (VEGF) mRNA and/or protein expression in psoriasis skin biopsies, serum and dHMVEC were assessed by immunohistology, dual-immunofluorescence, real-time PCR, ELISA and Western blotting. A-SAA-induced angiogenesis and invasion in the presence of Notch-1 siRNA was assessed by matrigel tube formation assays and Transwell invasion assay. Increased Notch-1, its ligand DLL-4 and Hrt-1 expression were demonstrated in lesional skin compared with non-lesional skin, with greatest expression observed in the dermal vasculature (P < 0.05). Dual-immunofluorescent staining demonstrated co-localization of Notch-1 to endothelial cell marker Factor VIII. A significant increase in A-SAA levels was demonstrated in psoriasis serum compared with healthy control serum (P < 0.05), and A-SAA expression was higher in lesional skin compared with non-lesional. In dHMVEC, A-SAA significantly induced Jagged-1, Hrt-1 and VEGF mRNA expression (P < 0.05) and activated Notch-1 IC indicative of transcriptional regulation. In contrast, A-SAA significantly inhibited DLL-4 mRNA expression (P < 0.05). Finally A-SAA-induced angiogenesis and invasion were inhibited by Notch-1 siRNA (P < 0.05). Notch receptor-ligand interactions mediate vascular dysfunction in psoriasis and may represent a potential therapeutic target.
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Affiliation(s)
- Peadar Rooney
- Department of Rheumatology, Dublin Academic Medical Centre and the Conway Institute of Biomolecular and Biomedical Research, UCD, Dublin 4, Ireland
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17
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Ahmad SM, Busser BW, Huang D, Cozart EJ, Michaud S, Zhu X, Jeffries N, Aboukhalil A, Bulyk ML, Ovcharenko I, Michelson AM. Machine learning classification of cell-specific cardiac enhancers uncovers developmental subnetworks regulating progenitor cell division and cell fate specification. Development 2014; 141:878-88. [PMID: 24496624 PMCID: PMC3912831 DOI: 10.1242/dev.101709] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The Drosophila heart is composed of two distinct cell types, the contractile cardial cells (CCs) and the surrounding non-muscle pericardial cells (PCs), development of which is regulated by a network of conserved signaling molecules and transcription factors (TFs). Here, we used machine learning with array-based chromatin immunoprecipitation (ChIP) data and TF sequence motifs to computationally classify cell type-specific cardiac enhancers. Extensive testing of predicted enhancers at single-cell resolution revealed the added value of ChIP data for modeling cell type-specific activities. Furthermore, clustering the top-scoring classifier sequence features identified novel cardiac and cell type-specific regulatory motifs. For example, we found that the Myb motif learned by the classifier is crucial for CC activity, and the Myb TF acts in concert with two forkhead domain TFs and Polo kinase to regulate cardiac progenitor cell divisions. In addition, differential motif enrichment and cis-trans genetic studies revealed that the Notch signaling pathway TF Suppressor of Hairless [Su(H)] discriminates PC from CC enhancer activities. Collectively, these studies elucidate molecular pathways used in the regulatory decisions for proliferation and differentiation of cardiac progenitor cells, implicate Su(H) in regulating cell fate decisions of these progenitors, and document the utility of enhancer modeling in uncovering developmental regulatory subnetworks.
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Affiliation(s)
- Shaad M Ahmad
- Laboratory of Developmental Systems Biology, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
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The Iroquois complex is required in the dorsal mesoderm to ensure normal heart development in Drosophila. PLoS One 2013; 8:e76498. [PMID: 24086746 PMCID: PMC3781054 DOI: 10.1371/journal.pone.0076498] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Accepted: 08/27/2013] [Indexed: 12/23/2022] Open
Abstract
Drosophila heart development is an invaluable system to study the orchestrated action of numerous factors that govern cardiogenesis. Cardiac progenitors arise within specific dorsal mesodermal regions that are under the influence of temporally coordinated actions of multiple signaling pathways. The Drosophila Iroquois complex (Iro-C) consists of the three homeobox transcription factors araucan (ara), caupolican (caup) and mirror (mirr). The Iro-C has been shown to be involved in tissue patterning leading to the differentiation of specific structures, such as the lateral notum and dorsal head structures and in establishing the dorsal-ventral border of the eye. A function for Iro-C in cardiogenesis has not been investigated yet. Our data demonstrate that loss of the whole Iro complex, as well as loss of either ara/caup or mirr only, affect heart development in Drosophila. Furthermore, the data indicate that the GATA factor Pannier requires the presence of Iro-C to function in cardiogenesis. Furthermore, a detailed expression pattern analysis of the members of the Iro-C revealed the presence of a possibly novel subpopulation of Even-skipped expressing pericardial cells and seven pairs of heart-associated cells that have not been described before. Taken together, this work introduces Iro-C as a new set of transcription factors that are required for normal development of the heart. As the members of the Iro-C may function, at least partly, as competence factors in the dorsal mesoderm, our results are fundamental for future studies aiming to decipher the regulatory interactions between factors that determine different cell fates in the dorsal mesoderm.
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The switch role of the Tmod4 in the regulation of balanced development between myogenesis and adipogenesis. Gene 2013; 532:263-71. [PMID: 24036428 DOI: 10.1016/j.gene.2013.08.088] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2013] [Revised: 08/16/2013] [Accepted: 08/28/2013] [Indexed: 11/21/2022]
Abstract
Tmod4 (Tropomodulin 4) is a member of Tmod family that plays important role in thin filament length regulation and myofibril assembly. We found that the expression levels of Tmod4 were higher in skeletal muscle and adipose tissues. However, the function and regulation of the Tmod4 gene in the myogenesis and adipogenesis remains unclear. In this study, we found that the expression of Tmod4 was decreased in myogenesis while increased in adipogenesis. Then, the transcriptional regulation analysis of Tmod4 promoter showed that Tmod4 could be regulated directly by myogenic factors and adipogenic factors. Furthermore, the roles of Tmod4 in the myogenesis and adipogenesis were confirmed by its over-expression in C2C12 cells and 3T3 cells, which suggested that Tmod4 could promote adipogenesis by up-regulating the adipogenic factors but moderately delay the myogenesis. These results indicated that the Tmod4 gene may play as a switch between myogenesis and adipogenesis, which resulted in the balanced development between skeletal muscle and adipose tissue. Therefore, the model for switch role of the Tmod4 in the balanced regulation between myogenesis and adipogenesis was proposed. It is showed that the expression of Tmod4 was activated in adipogenesis by adipogenic factors while inhibited in myogenesis by myogenic factors. Moreover, Tmod4 could promote adipogenesis by up-regulating the expression of adipogenic factors while moderately delaying the myogenesis. Our study provides an important basis for further understanding the regulation and function of porcine Tmod4 in muscle and fat development.
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20
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Upadhyay A, Kandachar V, Zitserman D, Tong X, Roegiers F. Sanpodo controls sensory organ precursor fate by directing Notch trafficking and binding γ-secretase. ACTA ACUST UNITED AC 2013; 201:439-48. [PMID: 23609534 PMCID: PMC3639393 DOI: 10.1083/jcb.201209023] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
In sensory organ precursor cells, Sanpodo can enhance or suppress Notch signaling by promoting interaction with Presenilin or driving receptor internalization, respectively. In Drosophila peripheral neurogenesis, Notch controls cell fates in sensory organ precursor (SOP) cells. SOPs undergo asymmetric cell division by segregating Numb, which inhibits Notch signaling, into the pIIb daughter cell after cytokinesis. In contrast, in the pIIa daughter cell, Notch is activated and requires Sanpodo, but its mechanism of action has not been elucidated. As Sanpodo is present in both pIIa and pIIb cells, a second role for Sanpodo in regulating Notch signaling in the low-Notch pIIb cell has been proposed. Here we demonstrate that Sanpodo regulates Notch signaling levels in both pIIa and pIIb cells via distinct mechanisms. The interaction of Sanpodo with Presenilin, a component of the γ-secretase complex, was required for Notch activation and pIIa cell fate. In contrast, Sanpodo suppresses Notch signaling in the pIIb cell by driving Notch receptor internalization. Together, these results demonstrate that a single protein can regulate Notch signaling through distinct mechanisms to either promote or suppress signaling depending on the local cellular context.
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Affiliation(s)
- Alok Upadhyay
- Fox Chase Cancer Center, Philadelphia, PA 19111, USA
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21
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Gao W, Sweeney C, Connolly M, Kennedy A, Ng CT, McCormick J, Veale DJ, Fearon U. Notch-1 mediates hypoxia-induced angiogenesis in rheumatoid arthritis. ACTA ACUST UNITED AC 2012; 64:2104-13. [PMID: 22275240 DOI: 10.1002/art.34397] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE To examine the effect of hypoxia on Notch-1 signaling pathway components and angiogenesis in inflammatory arthritis. METHODS The expression and regulation of Notch-1, its ligand delta-like protein 4 (DLL-4) and downstream signaling components (hairy-related transcription factor 1 [HRT-1], HRT-2), and hypoxia-inducible factor 1α (HIF-1α) under normoxic and hypoxic conditions (1-3%) were assessed in synovial tissue specimens from patients with inflammatory arthritis and controls and in human dermal microvascular endothelial cells (HDMECs) by immunohistology, dual immunofluorescence staining (Notch-1/factor VIII), Western blotting, and real-time polymerase chain reaction. In vivo synovial tissue oxygen levels (tissue PO2) were measured under direct visualization at arthroscopy. HDMEC activation under hypoxic conditions in the presence of Notch-1 small interfering RNA (siRNA), the γ-secretase inhibitor DAPT, or dimethyloxalylglycine (DMOG) was assessed by Matrigel tube formation assay, migration assay, invasion assay, and matrix metalloproteinase 2 (MMP-2)/MMP-9 zymography. RESULTS Expression of Notch-1, its ligand DLL-4, and HRT-1 was demonstrated in synovial tissue, with the strongest expression localized to perivascular/vascular regions. Localization of Notch-1 to synovial endothelium was confirmed by dual immunofluorescence staining. Notch-1 intracellular domain (NICD) expression was significantly higher in synovial tissue from patients with tissue PO2 of <20 mm Hg (<3% O2) than in those with tissue PO2 of >20 mm Hg (>3% O2). Exposure of HDMECs to 3% hypoxia induced HIF-1α and NICD protein expression and DLL-4, HRT-1, and HRT-2 messenger RNA expression. DMOG directly induced NICD expression, while Notch-1 siRNA inhibited hypoxia-induced HIF-1α expression, suggesting that Notch-1/HIF-1α signaling is bidirectional. Finally, 3% hypoxia-induced angiogenesis, endothelial cell migration, endothelial cell invasion, and proMMP-2 and proMMP-9 activities were inhibited by Notch-1 siRNA and/or the γ-secretase inhibitor DAPT. CONCLUSION Our findings indicate that Notch-1 is expressed in synovial tissue and that increased NICD expression is associated with low in vivo tissue PO2. Furthermore, Notch-1/HIF-1α interactions mediate hypoxia-induced angiogenesis and invasion in inflammatory arthritis.
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Affiliation(s)
- Wei Gao
- Dublin Academic Medical Centre, St. Vincent's University Hospital, and University College Dublin, Dublin, Ireland
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22
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Andersen P, Uosaki H, Shenje LT, Kwon C. Non-canonical Notch signaling: emerging role and mechanism. Trends Cell Biol 2012; 22:257-65. [PMID: 22397947 DOI: 10.1016/j.tcb.2012.02.003] [Citation(s) in RCA: 167] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Revised: 01/27/2012] [Accepted: 02/09/2012] [Indexed: 02/08/2023]
Abstract
Notch is an ancient transmembrane receptor with crucial roles in cell-fate choices. Although the 'canonical' Notch pathway and its core members are well established - involving ligand-induced cleavage of Notch for transcriptional regulation - it has been unclear whether Notch can also function independently of ligand and transcription ('non-canonically') through a common mechanism. Recent studies suggest that Notch can non-canonically exert its biological functions by post-translationally targeting Wnt/β-catenin signaling, an important cellular and developmental regulator. The non-canonical Notch pathway appears to be highly conserved from flies to mammals. Here, we discuss the emerging conserved mechanism and role of ligand/transcription-independent Notch signaling in cell and developmental biology.
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Affiliation(s)
- Peter Andersen
- Division of Cardiology, Department of Medicine, Johns Hopkins University, 720 Rutland Avenue, Baltimore, MD 21205, USA
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23
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Rasmussen TL, Kweon J, Diekmann MA, Belema-Bedada F, Song Q, Bowlin K, Shi X, Ferdous A, Li T, Kyba M, Metzger JM, Koyano-Nakagawa N, Garry DJ. ER71 directs mesodermal fate decisions during embryogenesis. Development 2011; 138:4801-12. [PMID: 21989919 DOI: 10.1242/dev.070912] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Er71 mutant embryos are nonviable and lack hematopoietic and endothelial lineages. To further define the functional role for ER71 in cell lineage decisions, we generated genetically modified mouse models. We engineered an Er71-EYFP transgenic mouse model by fusing the 3.9 kb Er71 promoter to the EYFP reporter gene. Using FACS and transcriptional profiling, we examined the EYFP(+) population of cells in Er71 mutant and wild-type littermates. In the absence of ER71, we observed an increase in the number of EYFP-expressing cells, increased expression of the cardiac molecular program and decreased expression of the hemato-endothelial program, as compared with wild-type littermate controls. We also generated a novel Er71-Cre transgenic mouse model using the same 3.9 kb Er71 promoter. Genetic fate-mapping studies revealed that the ER71-expressing cells give rise to the hematopoietic and endothelial lineages in the wild-type background. In the absence of ER71, these cell populations contributed to alternative mesodermal lineages, including the cardiac lineage. To extend these analyses, we used an inducible embryonic stem/embryoid body system and observed that ER71 overexpression repressed cardiogenesis. Together, these studies identify ER71 as a critical regulator of mesodermal fate decisions that acts to specify the hematopoietic and endothelial lineages at the expense of cardiac lineages. This enhances our understanding of the mechanisms that govern mesodermal fate decisions early during embryogenesis.
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Affiliation(s)
- Tara L Rasmussen
- Lillehei Heart Institute, University of Minnesota, Minneapolis, MN 55455, USA
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Abstract
The Golgi is essential for processing proteins and sorting them, as well as plasma membrane components, to their final destinations. Not surprisingly, this organelle, a major compartment of the secretory pathway, is an important venue for regulating many aspects of development in both invertebrates and vertebrates. Through its role as a site for protein cleavage and glycosylation as well as through changes in its spatial organization and secretory trafficking, the Golgi exerts highly specific effects on cellular differentiation and morphogenesis by spatially and temporally constraining developmental pathways.
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Beres BJ, George R, Lougher EJ, Barton M, Verrelli BC, McGlade CJ, Rawls JA, Wilson-Rawls J. Numb regulates Notch1, but not Notch3, during myogenesis. Mech Dev 2011; 128:247-57. [DOI: 10.1016/j.mod.2011.02.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2010] [Revised: 02/18/2011] [Accepted: 02/22/2011] [Indexed: 12/18/2022]
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Affiliation(s)
- Michela Noseda
- From the British Heart Foundation Centre of Research Excellence (M.N., M.D.S.), National Heart and Lung Institute, Imperial College London; and the Weatherall Institute of Molecular Medicine (T.P., F.C.S., R.P.), University of Oxford, United Kingdom
| | - Tessa Peterkin
- From the British Heart Foundation Centre of Research Excellence (M.N., M.D.S.), National Heart and Lung Institute, Imperial College London; and the Weatherall Institute of Molecular Medicine (T.P., F.C.S., R.P.), University of Oxford, United Kingdom
| | - Filipa C. Simões
- From the British Heart Foundation Centre of Research Excellence (M.N., M.D.S.), National Heart and Lung Institute, Imperial College London; and the Weatherall Institute of Molecular Medicine (T.P., F.C.S., R.P.), University of Oxford, United Kingdom
| | - Roger Patient
- From the British Heart Foundation Centre of Research Excellence (M.N., M.D.S.), National Heart and Lung Institute, Imperial College London; and the Weatherall Institute of Molecular Medicine (T.P., F.C.S., R.P.), University of Oxford, United Kingdom
| | - Michael D. Schneider
- From the British Heart Foundation Centre of Research Excellence (M.N., M.D.S.), National Heart and Lung Institute, Imperial College London; and the Weatherall Institute of Molecular Medicine (T.P., F.C.S., R.P.), University of Oxford, United Kingdom
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Pece S, Confalonieri S, R Romano P, Di Fiore PP. NUMB-ing down cancer by more than just a NOTCH. BIOCHIMICA ET BIOPHYSICA ACTA 2011; 1815:26-43. [PMID: 20940030 DOI: 10.1016/j.bbcan.2010.10.001] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2010] [Revised: 09/30/2010] [Accepted: 10/02/2010] [Indexed: 02/07/2023]
Abstract
The protein Numb does not live up to its name. This passive-sounding protein is anything but spent. Originally identified as a cell-fate determinant in Drosophila development, Numb received a good deal of attention as an inhibitor of the Notch receptor signaling pathway. It turns out, however, that Numb does a lot more than simply regulate Notch. It has been implicated in a variety of biochemical pathways connected with signaling (it regulates Notch-, Hedgehog- and TP53-activated pathways), endocytosis (it is involved in cargo internalization and recycling), determination of polarity (it interacts with the PAR complex, and regulates adherens and tight junctions), and ubiquitination (it exploits this mechanism to regulate protein function and stability). This complex biochemical network lies at the heart of Numb's involvement in diverse cellular phenotypes, including cell fate developmental decisions, maintenance of stem cell compartments, regulation of cell polarity and adhesion, and migration. Considering its multifaceted role in cellular homeostasis, it is not surprising that Numb has been implicated in cancer as a tumor suppressor. Our major goal here is to explain the cancer-related role of Numb based on our understanding of its role in cell physiology. We will attempt to do this by reviewing the present knowledge of Numb at the biochemical and functional level, and by integrating its apparently heterogeneous functions into a unifying scenario, based on our recently proposed concept of the "endocytic matrix". Finally, we will discuss the role of Numb in the maintenance of the normal stem cell compartment, as a starting point to interpret the tumor suppressor function of Numb in the context of the cancer stem cell hypothesis.
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Affiliation(s)
- Salvatore Pece
- Fondazione Istituto FIRC di Oncologia Molecolare, Via Adamello 16, 20139, Milan, Italy
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28
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Babaoglan AB, O'Connor-Giles KM, Mistry H, Schickedanz A, Wilson BA, Skeath JB. Sanpodo: a context-dependent activator and inhibitor of Notch signaling during asymmetric divisions. Development 2009; 136:4089-98. [PMID: 19906847 DOI: 10.1242/dev.040386] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Asymmetric cell divisions generate sibling cells of distinct fates ('A', 'B') and constitute a fundamental mechanism that creates cell-type diversity in multicellular organisms. Antagonistic interactions between the Notch pathway and the intrinsic cell-fate determinant Numb appear to regulate asymmetric divisions in flies and vertebrates. During these divisions, productive Notch signaling requires sanpodo, which encodes a novel transmembrane protein. Here, we demonstrate that Drosophila sanpodo plays a dual role to regulate Notch signaling during asymmetric divisions - amplifying Notch signaling in the absence of Numb in the 'A' daughter cell and inhibiting Notch signaling in the presence of Numb in the 'B' daughter cell. In so doing, sanpodo ensures the asymmetry in Notch signaling levels necessary for the acquisition of distinct fates by the two daughter cells. These findings answer long-standing questions about the restricted ability of Numb and Sanpodo to inhibit and to promote, respectively, Notch signaling during asymmetric divisions.
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Affiliation(s)
- A Burcu Babaoglan
- Program in Developmental Biology, Washington University School of Medicine, St Louis, MO 63110, USA
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29
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Purow B. Notch inhibitors as a new tool in the war on cancer: a pathway to watch. Curr Pharm Biotechnol 2009; 10:154-60. [PMID: 19199947 DOI: 10.2174/138920109787315060] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Notch was first recognized as an important developmental pathway in Drosophila in the first half of the 20th century. Many decades later, this pathway has been found to play central roles in humans in stem cell maintenance, cell fate decisions, and in cancer as well. Notch family members are being revealed as oncogenes in an ever-increasing number of cancers. Though significant progress has been made in dissecting the complex workings of this signaling pathway, there are very limited options available for Notch inhibitors. However, the pioneering class of Notch inhibitors is already in clinical trials for two cancer types. This review will address the current state-of-the-art, agents in the pipeline, and potential strategies for future Notch inhibitors. Successful development of Notch inhibitors in the clinic holds great promise as a new anti-cancer strategy.
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Affiliation(s)
- Benjamin Purow
- Neuro-Oncology Division, Neurology Department, University of Virginia, Charlottesville, VA, USA.
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30
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Sellin J, Drechsler M, Nguyen HT, Paululat A. Antagonistic function of Lmd and Zfh1 fine tunes cell fate decisions in the Twi and Tin positive mesoderm of Drosophila melanogaster. Dev Biol 2008; 326:444-55. [PMID: 19028484 DOI: 10.1016/j.ydbio.2008.10.041] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2008] [Revised: 09/30/2008] [Accepted: 10/29/2008] [Indexed: 10/21/2022]
Abstract
In this study we show that cell fate decisions in the dorsal and lateral mesoderm of Drosophila melanogaster depend on the antagonistic action of the Gli-like transcription factor Lame duck (Lmd) and the zinc finger homeodomain factor Zfh1. Lmd expression leads to the reduction of Zfh1 positive cell types, thereby restricting the number of Odd-skipped (Odd) positive and Tinman (Tin) positive pericardial cells in the dorsal mesoderm. In more lateral regions, ectopic activation of Zfh1 or loss of Lmd leads to an excess of adult muscle precursor (AMP) like cells. We also observed that Lmd is co-expressed with Tin in the early dorsal mesoderm and leads to a reduction of Tin expression in cells destined to become dorsal fusion competent myoblasts (FCMs). In the absence of Lmd function, these cells remain Tin positive and develop as Tin positive pericardial cells although they do not express Zfh1. We show further that Tin repression and pericardial restriction in the dorsal mesoderm facilitated by Lmd is instructed by a late Decapentaplegic (Dpp) signal that is abolished in embryos carrying the disk region mutation dpp(d6).
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Affiliation(s)
- Julia Sellin
- Universität Osnabrück, Fachbereich Biologie/Chemie - Zoologie/Entwicklungsbiologie, Osnabrück, Germany
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31
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Collesi C, Zentilin L, Sinagra G, Giacca M. Notch1 signaling stimulates proliferation of immature cardiomyocytes. ACTA ACUST UNITED AC 2008; 183:117-28. [PMID: 18824567 PMCID: PMC2557047 DOI: 10.1083/jcb.200806091] [Citation(s) in RCA: 130] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The identification of the molecular mechanisms controlling cardiomyocyte proliferation during the embryonic, fetal, and early neonatal life appears of paramount interest in regard to exploiting this information to promote cardiac regeneration. Here, we show that the proliferative potential of neonatal rat cardiomyocytes is powerfully stimulated by the sustained activation of the Notch pathway. We found that Notch1 is expressed in proliferating ventricular immature cardiac myocytes (ICMs) both in vitro and in vivo, and that the number of Notch1-positive cells in the heart declines with age. Notch1 expression in ICMs paralleled the expression of its Jagged1 ligand on non-myocyte supporting cells. The inhibition of Notch signaling in ICMs blocked their proliferation and induced apoptosis; in contrast, its activation by Jagged1 or by the constitutive expression of its activated form using an adeno-associated virus markedly stimulated proliferative signaling and promoted ICM expansion. Maintenance or reactivation of Notch signaling in cardiac myocytes might represent an interesting target for innovative regenerative therapy.
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Affiliation(s)
- Chiara Collesi
- Molecular Medicine Laboratory, International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
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32
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Bryantsev AL, Cripps RM. Cardiac gene regulatory networks in Drosophila. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2008; 1789:343-53. [PMID: 18849017 DOI: 10.1016/j.bbagrm.2008.09.002] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2008] [Revised: 08/09/2008] [Accepted: 09/09/2008] [Indexed: 11/29/2022]
Abstract
The Drosophila system has proven a powerful tool to help unlock the regulatory processes that occur during specification and differentiation of the embryonic heart. In this review, we focus upon a temporal analysis of the molecular events that result in heart formation in Drosophila, with a particular emphasis upon how genomic and other cutting-edge approaches are being brought to bear upon the subject. We anticipate that systems-level approaches will contribute greatly to our comprehension of heart development and disease in the animal kingdom.
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Affiliation(s)
- Anton L Bryantsev
- Department of Biology, University of New Mexico, Albuquerque, NM 87131-0001, USA
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33
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Gude NA, Emmanuel G, Wu W, Cottage CT, Fischer K, Quijada P, Muraski JA, Alvarez R, Rubio M, Schaefer E, Sussman MA. Activation of Notch-mediated protective signaling in the myocardium. Circ Res 2008; 102:1025-35. [PMID: 18369158 DOI: 10.1161/circresaha.107.164749] [Citation(s) in RCA: 147] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The Notch network regulates multiple cellular processes, including cell fate determination, development, differentiation, proliferation, apoptosis, and regeneration. These processes are regulated via Notch-mediated activity that involves hepatocyte growth factor (HGF)/c-Met receptor and phosphatidylinositol 3-kinase/Akt signaling cascades. The impact of HGF on Notch signaling was assessed following myocardial infarction as well as in cultured cardiomyocytes. Notch1 is activated in border zone cardiomyocytes coincident with nuclear c-Met following infarction. Intramyocardial injection of HGF enhances Notch1 and Akt activation in adult mouse myocardium. Corroborating evidence in cultured cardiomyocytes shows treatment with HGF or insulin increases levels of Notch effector Hes1 in immunoblots, whereas overexpression of activated Notch intracellular domain prompts a 3-fold increase in phosphorylated Akt. Infarcted hearts injected with adenoviral vector expressing Notch intracellular domain treatment exhibit improved hemodynamic function in comparison with control mice after 4 weeks, implicating Notch signaling in a cardioprotective role following cardiac injury. These results indicate Notch activation in cardiomyocytes is mediated through c-Met and Akt survival signaling pathways, and Notch1 signaling in turn enhances Akt activity. This mutually supportive crosstalk suggests a positive survival feedback mechanism between Notch and Akt signaling in adult myocardium following injury.
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Affiliation(s)
- Natalie A Gude
- San Diego State University Heart Institute, Department of Biology, San Diego State University, San Diego, CA 92182, USA
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34
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Tögel M, Pass G, Paululat A. The Drosophila wing hearts originate from pericardial cells and are essential for wing maturation. Dev Biol 2008; 318:29-37. [PMID: 18430414 DOI: 10.1016/j.ydbio.2008.02.043] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2007] [Revised: 02/14/2008] [Accepted: 02/15/2008] [Indexed: 11/19/2022]
Abstract
In addition to the heart proper, insects possess wing hearts in the thorax to ensure regular hemolymph flow through the narrow wings. In Drosophila, the wing hearts consist of two bilateral muscular pumps of unknown origin. Here, we present the first developmental study on these organs and report that the wing hearts originate from eight embryonic progenitor cells arising in two pairs in parasegments 4 and 5. These progenitors represent a so far undescribed subset of the Even-skipped positive pericardial cells (EPC) and are characterized by the early loss of tinman expression in contrast to the continuously Tinman positive classical EPCs. Ectopic expression of Tinman in the wing heart progenitors omits organ formation, indicating a crucial role for Tinman during progenitor specification. The subsequent postembryonic development is a highly dynamic process, which includes proliferation and two relocation events. Adults lacking wing hearts display a severe wing phenotype and are unable to fly. The phenotype is caused by omitted clearance of the epidermal cells from the wings during maturation, which inhibits the formation of a flexible wing blade. This indicates that wing hearts are required for proper wing morphogenesis and functionality.
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Affiliation(s)
- Markus Tögel
- Department of Biology, University of Osnabrück, Zoology/Developmental Biology, Barbarastrasse 11, D-49069 Osnabrück, Germany
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35
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Abstract
Stem cells self-renew but also give rise to daughter cells that are committed to lineage-specific differentiation. To achieve this remarkable task, they can undergo an intrinsically asymmetric cell division whereby they segregate cell fate determinants into only one of the two daughter cells. Alternatively, they can orient their division plane so that only one of the two daughter cells maintains contact with the niche and stem cell identity. These distinct pathways have been elucidated mostly in Drosophila. Although the molecules involved are highly conserved in vertebrates, the way they act is tissue specific and sometimes very different from invertebrates.
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Affiliation(s)
- Juergen A Knoblich
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Dr. Bohr Gasse 3, 1030 Vienna, Austria.
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36
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High FA, Epstein JA. The multifaceted role of Notch in cardiac development and disease. Nat Rev Genet 2008; 9:49-61. [PMID: 18071321 DOI: 10.1038/nrg2279] [Citation(s) in RCA: 221] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Notch receptors and their cognate ligands transduce crucial signals between cells in various tissues, and have been conserved across millions of years of evolution. Mutations in Notch signalling components result in congenital heart defects in humans and mice, demonstrating an essential role for Notch in cardiovascular development. The results of recent experiments implicate this signalling pathway in many stages of heart development, and provide mechanistic insight into the vital functions of Notch in the aetiology of several common forms of paediatric and adult cardiac disease.
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Affiliation(s)
- Frances A High
- Department of Cell and Developmental Biology and the Cardiovascular Institute, University of Pennsylvania, 421 Curie Boulevard, Philadelphia, Pennsylvania 19104, USA
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37
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Watanabe Y, Kokubo H, Miyagawa-Tomita S, Endo M, Igarashi K, Aisaki KI, Kanno J, Saga Y. Activation of Notch1 signaling in cardiogenic mesoderm induces abnormal heart morphogenesis in mouse. Development 2006; 133:1625-34. [PMID: 16554359 DOI: 10.1242/dev.02344] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Notch signaling is implicated in many developmental processes. In our current study, we have employed a transgenic strategy to investigate the role of Notch signaling during cardiac development in the mouse. Cre recombinase-mediated Notch1 (NICD1) activation in the mesodermal cell lineage leads to abnormal heart morphogenesis, which is characterized by deformities of the ventricles and atrioventricular (AV) canal. The major defects observed include impaired ventricular myocardial differentiation, the ectopic appearance of cell masses in the AV cushion, the right-shifted interventricular septum (IVS) and impaired myocardium of the AV canal. However, the fates of the endocardium and myocardium were not disrupted in NICD1-activated hearts. One of the Notch target genes, Hesr1, was found to be strongly induced in both the ventricle and the AV canal of NICD1-activated hearts. However, a knockout of the Hesr1 gene from NICD-activated hearts rescues only the abnormality of the AV myocardium. We searched for additional possible targets of NICD1 activation by GeneChip analysis and found that Wnt2, Bmp6, jagged 1 and Tnni2 are strongly upregulated in NICD1-activated hearts, and that the activation of these genes was also observed in the absence of Hesr1. Our present study thus indicates that the Notch1 signaling pathway plays a suppressive role both in AV myocardial differentiation and the maturation of the ventricular myocardium.
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Affiliation(s)
- Yusuke Watanabe
- Division of Mammalian Development, National Institute of Genetics, Yata 1111, Mishima 411-8540, Japan
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38
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Albrecht S, Wang S, Holz A, Bergter A, Paululat A. The ADAM metalloprotease Kuzbanian is crucial for proper heart formation in Drosophila melanogaster. Mech Dev 2006; 123:372-87. [PMID: 16713197 DOI: 10.1016/j.mod.2006.03.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2006] [Revised: 03/07/2006] [Accepted: 03/09/2006] [Indexed: 10/24/2022]
Abstract
We have screened a collection of EMS mutagenized fly lines in order to identify genes involved in cardiogenesis. In the present work, we have studied a group of alleles exhibiting a hypertrophic heart. Our analysis revealed that the ADAM protein (A Disintegrin And Metalloprotease) Kuzbanian, which is the functional homologue of the vertebrate ADAM10, is crucial for proper heart formation. ADAMs are a family of transmembrane proteins that play a critical role during the proteolytic conversion (shedding) of membrane bound proteins to soluble forms. Enzymes harboring a sheddase function recently became candidates for causing several congenital diseases, like distinct forms of the Alzheimer disease. ADAMs play also a pivotal role during heart formation and vascularisation in vertebrates, therefore mutations in ADAM genes potentially could cause congenital heart defects in humans. In Drosophila, the zygotic loss of an active form of the Kuzbanian protein results in a dramatic excess of cardiomyocytes, accompanied by a loss of pericardial cells. Our data presented herein suggest that Kuzbanian acts during lateral inhibition within the cardiac primordium. Furthermore we discuss a second function of Kuzbanian in heart cell morphogenesis.
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Affiliation(s)
- Stefanie Albrecht
- Universität Osnabrück, Fachbereich Biologie/Chemie, Zoologie, Barbarastrasse 11, D-49069 Osnabrück, Germany
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39
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Popichenko D, Paululat A. Cell fate decisions in the Drosophila dorsal vessel depend on the multiadapter protein inscuteable. Genesis 2005; 40:218-22. [PMID: 15593331 DOI: 10.1002/gene.20080] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The Drosophila dorsal vessel consists of two cell types, contractile cardiomyoblasts that form a linear tube-like structure, and the loosely associated pericardial cells. All heart cells originate during embryogenesis from the early dorsal mesoderm under the influence of external and internal signals. Recently, it was shown that a subset of heart cells arise throughout asymmetric cell division, dependent on the function of Notch, Sanpodo, and Numb. Here, we show that Inscuteable, a multiadapter protein required for asymmetric cell division, participates in the formation of specific heart cells to distinguish between a myogenic (cardiomyoblast) and a nonmyogenic (pericardial cell) fate.
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40
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Bhalerao S, Berdnik D, Török T, Knoblich JA. Localization-Dependent and -Independent Roles of Numb Contribute to Cell-Fate Specification in Drosophila. Curr Biol 2005; 15:1583-90. [PMID: 16139215 DOI: 10.1016/j.cub.2005.07.061] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2005] [Revised: 07/11/2005] [Accepted: 07/14/2005] [Indexed: 11/23/2022]
Abstract
During asymmetric cell division, protein determinants are segregated into one of the two daughter cells. The Numb protein acts as a segregating determinant during both mouse and Drosophila development. In flies, Numb localizes asymmetrically and is required for cell-fate specification in the central and peripheral nervous systems, as well as during muscle and heart development. Whether its asymmetric segregation is important to the performance of these functions is not firmly established. Here, we demonstrate that Numb acts both in a localization-dependent and in a localization-independent manner. We have generated numb mutants that affect only the asymmetric localization of the protein during mitosis. We demonstrate that asymmetric segregation of Numb into one of the two daughter cells is absolutely essential for cell-fate specification in the Drosophila peripheral nervous system. Numb localization is also essential in MP2 neuroblasts in the central nervous system and during muscle development. Surprisingly, in dividing ganglion mother cells or during heart development, Numb function is independent of its ability to segregate asymmetrically in mitosis. Our results suggest that two classes of asymmetric cell division exist, each with different requirements for asymmetric inheritance of cell-fate determinants.
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Affiliation(s)
- Sheetal Bhalerao
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Dr. Bohr Gasse 3-5, 1030 Vienna, Austria
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41
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Venters SJ, Ordahl CP. Asymmetric cell divisions are concentrated in the dermomyotome dorsomedial lip during epaxial primary myotome morphogenesis. ACTA ACUST UNITED AC 2005; 209:449-60. [PMID: 15891908 DOI: 10.1007/s00429-005-0461-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/15/2005] [Indexed: 10/25/2022]
Abstract
To determine if somitic stem cell pools could be identified by an intrinsic difference in mitotic behaviour, the orientation of mitoses in the dermomyotome epithelium was analysed. We describe a concentration of apico-basal mitoses within the dermomyotome dorsomedial lip (DML). The occurrence of apico-basal divisions is closely associated with asymmetric localisation of the notch pathway factor numb, allowing description of such divisions as asymmetric. In contrast, planar divisions, occurring in the plane of the epithelium, are symmetric. Further, we show that the DML environmental niche is sufficient to promote numb expression in epaxial dermomyotome tissue that does not normally express this factor. These data provide, for the first time, a non-retrospective tracing analysis of the mechanism by which the DML fulfils the stem-cell pool role it plays during epaxial primary myotome morphogenesis.
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Affiliation(s)
- Sara J Venters
- Department of Anatomy and Cardiovascular Research Institute, University of California San Francisco, San Francisco, CA 94143, USA
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42
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Chen J, Xu J, Zhao W, Hu G, Cheng H, Kang Y, Xie Y, Lu Y. Characterization of human LNX, a novel ligand of Numb protein X that is downregulated in human gliomas. Int J Biochem Cell Biol 2005; 37:2273-83. [PMID: 16002321 DOI: 10.1016/j.biocel.2005.02.028] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2004] [Revised: 01/03/2005] [Accepted: 02/13/2005] [Indexed: 11/28/2022]
Abstract
Gliomas are major tumors of the central nervous system with a wide spectrum of different tumor types. Ligand of Numb protein X (LNX) is PDZ domain containing protein that interacts with cell fate determinant Numb. cDNA microarray analysis was used to determine the expression of 13,939 genes in a set of 18 gliomas. It showed that human LNX was downregulated in 100% of gliomas including low- and high-grade ones, which was confirmed by Northern blot. In situ hybridization analysis revealed that LNX was lowly expressed in cytoplasm of glioma cells. Thus, LNX might act as a diagnostic marker and a potential therapeutic target for glioma. Two-hybrid screen in yeast was used to identify human LNX interacting proteins important for LNX function. It showed that human LNX interacted with Ski interacting protein (SKIP) via PDZ domains. The co-immunoprecipitation results suggested that LNX interacted with SKIP in HEK293 cells. LNX could affect the subcellular localization of Numb, which indicated that LNX might function as a molecular anchor that localized Numb to the subcellular site of its interaction with Notch. The presence of multiple protein binding domains involved in signal transduction and interaction with Numb and SKIP suggested an important role for LNX in tumorogenesis.
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Affiliation(s)
- Juxiang Chen
- Department of Neurosurgery, ChangZheng Hospital, Second Military Medical University, Shanghai 200003, PR China
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43
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Harbison ST, Yamamoto AH, Fanara JJ, Norga KK, Mackay TFC. Quantitative trait loci affecting starvation resistance in Drosophila melanogaster. Genetics 2005; 166:1807-23. [PMID: 15126400 PMCID: PMC1470806 DOI: 10.1534/genetics.166.4.1807] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The ability to withstand periods of scarce food resources is an important fitness trait. Starvation resistance is a quantitative trait controlled by multiple interacting genes and exhibits considerable genetic variation in natural populations. This genetic variation could be maintained in the face of strong selection due to a trade-off in resource allocation between reproductive activity and individual survival. Knowledge of the genes affecting starvation tolerance and the subset of genes that affect variation in starvation resistance in natural populations would enable us to evaluate this hypothesis from a quantitative genetic perspective. We screened 933 co-isogenic P-element insertion lines to identify candidate genes affecting starvation tolerance. A total of 383 P-element insertions induced highly significant and often sex-specific mutational variance in starvation resistance. We also used deficiency complementation mapping followed by complementation to mutations to identify 12 genes contributing to variation in starvation resistance between two wild-type strains. The genes we identified are involved in oogenesis, metabolism, and feeding behaviors, indicating a possible link to reproduction and survival. However, we also found genes with cell fate specification and cell proliferation phenotypes, which implies that resource allocation during development and at the cellular level may also influence the phenotypic response to starvation.
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Affiliation(s)
- Susan T Harbison
- Department of Genetics and W M Keck Center for Behavioral Biology, North Carolina State University, Raleigh, North Carolina 27695, USA
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44
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Soler C, Daczewska M, Da Ponte JP, Dastugue B, Jagla K. Coordinated development of muscles and tendons of the Drosophila leg. Development 2004; 131:6041-51. [PMID: 15537687 DOI: 10.1242/dev.01527] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Since Miller's morphological description, the Drosophila leg musculature and its formation has not been revisited. Here, using a set of GFP markers and confocal microscopy, we analyse Drosophila leg muscle development, and describe all the muscles and tendons present in the adult leg. Importantly, we provide for the first time evidence for tendons located internally within leg segments. By visualising muscle and tendon precursors, we demonstrate that leg muscle development is closely associated with the formation of internal tendons. In the third instars discs, in the vicinity of tendon progenitors, some Twist-positive myoblasts start to express the muscle founder cell marker dumbfounded (duf). Slightly later, in the early pupa, epithelial tendon precursors invaginate inside the developing leg segments, giving rise to the internal string-like tendons. The tendon-associated duf-lacZ-expressing muscle founders are distributed along the invaginating tendon precursors and then fuse with surrounding myoblasts to form syncytial myotubes. At mid-pupation, these myotubes grow towards their epithelial insertion sites, apodemes, and form links between internally located tendons and the leg epithelium. This leads to a stereotyped pattern of multifibre muscles that ensures movement of the adult leg.
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Affiliation(s)
- Cédric Soler
- INSERM U.384, Faculté de Médecine, 28 Place Henri Dunant, 63001 Clermont Ferrand, France
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45
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Kong KY, Kedes L. Cytoplasmic Nuclear Transfer of the Actin-capping Protein Tropomodulin. J Biol Chem 2004; 279:30856-64. [PMID: 15123707 DOI: 10.1074/jbc.m302845200] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Tropomodulin (Tmod) is a cytoskeletal actin-capping protein that interacts with tropomyosin at the pointed end of actin filaments. E-Tmod is an isoform that expresses predominantly in cardiac cells and slow skeletal muscle fibers. We unexpectedly discovered significant levels of Tmod in nuclei and then defined peptide domains in Tmod responsible for nuclear import and export. These domains resemble, and function as, a nuclear export signal (NES) and a pattern 4 nuclear localization signal (NLS). Both motifs are conserved in other Tmod isoforms and across species. Comparisons of wild-type Tmod and Tmod carrying mutations in these peptide domains revealed that Tmod normally traffics through the nucleus. These observations logically presuppose that Tmod functions may include a nuclear role. Indeed, increasing Tmod in the nucleus severely hampered myogenic differentiation and selectively suppressed muscle-specific gene expression (endogenous p21, myosin heavy chain, myogenin, and Tmod) but did not affect endogenous glyceraldehyde-3-phosphate dehydrogenase or expression from a transfected E-GFP vector. These results suggest that, at least in myogenic cells, nuclear Tmod may be involved in the differentiation process.
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MESH Headings
- Actins/chemistry
- Active Transport, Cell Nucleus
- Amino Acid Motifs
- Animals
- Blotting, Northern
- Blotting, Western
- Carrier Proteins/chemistry
- Carrier Proteins/metabolism
- Cell Differentiation
- Cell Line
- Cell Nucleus/metabolism
- Cells, Cultured
- Cytoplasm/metabolism
- Cytoskeleton/metabolism
- Electrophoresis, Polyacrylamide Gel
- Green Fluorescent Proteins
- Lentivirus/genetics
- Luminescent Proteins/metabolism
- Mice
- Mice, Inbred C3H
- Microfilament Proteins/chemistry
- Microfilament Proteins/metabolism
- Microscopy, Fluorescence
- Microscopy, Phase-Contrast
- Models, Genetic
- Mutagenesis, Site-Directed
- Mutation
- Myocytes, Cardiac/cytology
- Nuclear Localization Signals
- Plasmids/metabolism
- Protein Isoforms
- Protein Structure, Tertiary
- RNA/metabolism
- RNA, Messenger/metabolism
- Rats
- Rats, Sprague-Dawley
- Recombinant Fusion Proteins/metabolism
- Transfection
- Tropomodulin
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Affiliation(s)
- Kimi Y Kong
- Institute for Genetic Medicine and Department of Biochemistry & Molecular Biology, Keck School of Medicine, University of Southern California, Los Angeles, California 90033, USA
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46
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Nie J, Li SSC, McGlade CJ. A novel PTB-PDZ domain interaction mediates isoform-specific ubiquitylation of mammalian Numb. J Biol Chem 2004; 279:20807-15. [PMID: 14990566 DOI: 10.1074/jbc.m311396200] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
LNX was originally cloned as a Numb PTB-binding molecule, and it was subsequently found to act as a RING finger-type E3 ubiquitin ligase for the ubiquitylation and degradation of mNumb. Numb is a PTB domain-containing protein that functions as an intrinsic determinant of cell fate in asymmetric cell division. In mammals, four protein isoforms arise from alternative mRNA splicing. Here we report that while all four protein isoforms bind to LNX, only p72 and p66 Numb isoforms are ubiquitylated and degraded. The p72 and p66 Numb proteins differ from the other two isoforms by the presence of an 11-amino acid sequence insert in the PTB domain (PTBi). We demonstrate that the isoform-specific ubiquitylation of mNumb is due to a novel interaction between the first PDZ domain (PDZ1) of LNX and the PTBi variant. Deletion of LNX PDZ1 domain resulted in loss of ubiquitylation and subsequent degradation of the PTBi form of Numb. Interestingly efficient PTBi ubiquitylation not only depends on association with the LNX PDZ1 domain but also requires binding to the canonical PTB-binding motif NPAY in LNX. Thus two distinct modes of PTBi-mediated interaction with LNX work in concert to allow the effective and specific degradation of the p72 and p66 isoforms of mNumb.
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Affiliation(s)
- Jing Nie
- The Arthur and Sonia Labatt Brain Tumor Research Centre, The Hospital for Sick Children and Department of Medical Biophysics, University of Toronto, 555 University Avenue, Toronto, Ontario M5G 1X8, Canada
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47
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Harbison ST, Yamamoto AH, Fanara JJ, Norga KK, Mackay TFC. Quantitative Trait Loci Affecting Starvation Resistance in Drosophila melanogaster. Genetics 2004. [DOI: 10.1093/genetics/166.4.1807] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
The ability to withstand periods of scarce food resources is an important fitness trait. Starvation resistance is a quantitative trait controlled by multiple interacting genes and exhibits considerable genetic variation in natural populations. This genetic variation could be maintained in the face of strong selection due to a trade-off in resource allocation between reproductive activity and individual survival. Knowledge of the genes affecting starvation tolerance and the subset of genes that affect variation in starvation resistance in natural populations would enable us to evaluate this hypothesis from a quantitative genetic perspective. We screened 933 co-isogenic P-element insertion lines to identify candidate genes affecting starvation tolerance. A total of 383 P-element insertions induced highly significant and often sex-specific mutational variance in starvation resistance. We also used deficiency complementation mapping followed by complementation to mutations to identify 12 genes contributing to variation in starvation resistance between two wild-type strains. The genes we identified are involved in oogenesis, metabolism, and feeding behaviors, indicating a possible link to reproduction and survival. However, we also found genes with cell fate specification and cell proliferation phenotypes, which implies that resource allocation during development and at the cellular level may also influence the phenotypic response to starvation.
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Affiliation(s)
- Susan T Harbison
- Department of Genetics and W. M. Keck Center for Behavioral Biology, North Carolina State University, Raleigh, North Carolina 27695
| | - Akihiko H Yamamoto
- Department of Genetics and W. M. Keck Center for Behavioral Biology, North Carolina State University, Raleigh, North Carolina 27695
| | - Juan J Fanara
- Department of Genetics and W. M. Keck Center for Behavioral Biology, North Carolina State University, Raleigh, North Carolina 27695
- Department of Ecology, Genetics, and Evolution, University of Buenos Aires, Buenos Aires 1428, Argentina
| | - Koenraad K Norga
- Howard Hughes Medical Institute, Department of Molecular and Human Genetics and Texas Children’s Cancer Center, Baylor College of Medicine, Houston, Texas 77030
| | - Trudy F C Mackay
- Department of Genetics and W. M. Keck Center for Behavioral Biology, North Carolina State University, Raleigh, North Carolina 27695
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48
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Irion U, Leptin M, Siller K, Fuerstenberg S, Cai Y, Doe CQ, Chia W, Yang X. Abstrakt, a DEAD box protein, regulates Insc levels and asymmetric division of neural and mesodermal progenitors. Curr Biol 2004; 14:138-44. [PMID: 14738736 DOI: 10.1016/j.cub.2004.01.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Asymmetric cell division generates cell diversity in bacteria, yeast, and higher eukaryotes. In Drosophila, both neural and muscle progenitors divide asymmetrically. In these cells the Inscuteable (Insc) protein complex coordinates cell polarity and spindle orientation. Abstrakt (Abs) is a DEAD-box protein that regulates aspects of cell polarity in oocytes and embryos. We use a conditional allele of abs to investigate its role in neural and muscle progenitor cell polarity. In neuroblasts we observe loss of apical Insc crescents, failure in basal protein targeting, and defects in spindle orientation. In the GMC4-2a cell we observe loss of apical Insc crescents, defects in basal protein targeting, and equalization of sibling neuron fates; muscle precursors show a similar equalization of sibling cell fates. These phenotypes resemble those of insc mutants; indeed, abs mutants show a striking loss of Insc protein levels but no change of insc RNA levels. Furthermore, we find that the Abs protein physically interacts with insc RNA. Our results demonstrate a novel role for Abs in the posttranscriptional regulation of insc expression, which is essential for proper cell polarity, spindle orientation, and the establishment of distinct sibling cell fates within embryonic neural and muscle progenitors.
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Affiliation(s)
- Uwe Irion
- Institut für Genetik, Universität zu Köln, Weyertal 121, D-50931, Cologne, Germany
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49
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Bidet Y, Jagla T, Da Ponte JP, Dastugue B, Jagla K. Modifiers of muscle and heart cell fate specification identified by gain-of-function screen in Drosophila. Mech Dev 2003; 120:991-1007. [PMID: 14550529 DOI: 10.1016/s0925-4773(03)00182-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The homeobox genes ladybird in Drosophila and their vertebrate counterparts Lbx1 genes display restricted expression patterns in a subset of muscle precursors and are both implicated in diversification of muscle cell fates. In order to gain new insights into mechanisms controlling conserved aspects of cell fate specification, we have performed a gain-of-function (GOF) screen for modifiers of the mesodermal expression of ladybird genes using a collection of EP element carrying Drosophila lines. Amongst the identified genes, several have been previously implicated in cell fate specification processes, thus validating the strategy of our screen. Observed GOF phenotypes have led us to identification of an important number of candidate genes, whose myogenic and/or cardiogenic functions remain to be investigated. Amongst them, the EP insertions close to rhomboid, yan and rac2 suggest new roles for these genes in diversification of muscle and/or heart cell lineages. The analysis of loss and GOF of rhomboid and yan reveals their new roles in specification of ladybird-expressing precursors of adult muscles (LaPs) and ladybird/tinman-positive pericardial cells. Observed phenotypes strongly suggest that rhomboid and yan act at the level of progenitor and founder cells and contribute to the diversification of mesodermal fates. Our analysis of rac2 phenotypes clearly demonstrates that the altered mesodermal level of Rho-GTPase Rac2 can influence specification of a number of cardiac and muscular cell types including those expressing ladybird. Finding that in rac2 mutants ladybird and even skipped-positive muscle founders are overproduced, indicate a new early function for this gene during segregation of muscle progenitors and/or specification of founder cells. Intriguingly, rhomboid, yan and rac2 act as conserved components of Receptor Tyrosine Kinases (RTKs) signalling pathways, suggesting that RTK signalling constitutes a part of a conserved regulatory network governing diversification of muscle and heart cell types.
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Affiliation(s)
- Yannick Bidet
- UMR INSERM U384-Faculté de Médecine, 28 Place Henri Dunant, 63001 Clermont-Ferrand, France
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50
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Lundell MJ, Lee HK, Pérez E, Chadwell L. The regulation of apoptosis by Numb/Notch signaling in the serotonin lineage of Drosophila. Development 2003; 130:4109-21. [PMID: 12874131 DOI: 10.1242/dev.00593] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Apoptosis is prevalent during development of the central nervous system (CNS), yet very little is known about the signals that specify an apoptotic cell fate. In this paper, we examine the role of Numb/Notch signaling in the development of the serotonin lineage of Drosophila and show that it is necessary for regulating apoptosis. Our results indicate that when Numb inhibits Notch signaling, cells undergo neuronal differentiation, whereas cells that maintain Notch signaling initiate apoptosis. The apoptosis inhibitor p35 can counteract Notch-mediated apoptosis and rescue cells within the serotonin lineage that normally undergo apoptosis. Furthermore, we observe tumor-like overproliferation of cells in the CNS when Notch signaling is reduced. These data suggest that the distribution of Numb during terminal mitotic divisions of the CNS can distinguish between a neuronal cell fate and programmed cell death.
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Affiliation(s)
- Martha J Lundell
- Department of Biology, University of Texas at San Antonio, San Antonio, TX 78249, USA.
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