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Sarvari P, Rasouli SJ, Allanki S, Stone OA, Sokol AM, Graumann J, Stainier DYR. The E3 ubiquitin-protein ligase Rbx1 regulates cardiac wall morphogenesis in zebrafish. Dev Biol 2021; 480:1-12. [PMID: 34363825 DOI: 10.1016/j.ydbio.2021.07.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Revised: 07/11/2021] [Accepted: 07/31/2021] [Indexed: 11/17/2022]
Abstract
Cardiac trabeculae are muscular ridge-like structures within the ventricular wall that are crucial for cardiac function. In zebrafish, these structures first form primarily through the delamination of compact wall cardiomyocytes (CMs). Although defects in proteasomal degradation have been associated with decreased cardiac function, whether they also affect cardiac development has not been extensively analyzed. Here we report a role during cardiac wall morphogenesis in zebrafish for the E3 ubiquitin-protein ligase Rbx1, which has been shown to regulate the degradation of key signaling molecules. Although development is largely unperturbed in zebrafish rbx1 mutant larvae, they exhibit CM multi-layering. This phenotype is not affected by blocking ErbB signaling, but fails to manifest itself in the absence of blood flow/cardiac contractility. Surprisingly, rbx1 mutants display ErbB independent Notch reporter expression in the myocardium. We generated tissue-specific rbx1 overexpression lines and found that endothelial, but not myocardial, specific rbx1 expression normalizes the cardiac wall morphogenesis phenotype. In addition, we found that pharmacological activation of Hedgehog signaling ameliorates the multi-layered myocardial wall phenotype in rbx1 mutants. Collectively, our data indicate that endocardial activity of Rbx1 is essential for cardiac wall morphogenesis.
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Affiliation(s)
- Pourya Sarvari
- Max Planck Institute for Heart and Lung Research, Department of Developmental Genetics, Bad Nauheim, 61231, Germany
| | - S Javad Rasouli
- Max Planck Institute for Heart and Lung Research, Department of Developmental Genetics, Bad Nauheim, 61231, Germany
| | - Srinivas Allanki
- Max Planck Institute for Heart and Lung Research, Department of Developmental Genetics, Bad Nauheim, 61231, Germany
| | - Oliver A Stone
- Max Planck Institute for Heart and Lung Research, Department of Developmental Genetics, Bad Nauheim, 61231, Germany
| | - Anna M Sokol
- Max Planck Institute for Heart and Lung Research, Department of Developmental Genetics, Bad Nauheim, 61231, Germany; Max Planck Institute for Heart and Lung Research, Biomolecular Mass Spectrometry, Bad Nauheim, 61231, Germany
| | - Johannes Graumann
- Max Planck Institute for Heart and Lung Research, Department of Developmental Genetics, Bad Nauheim, 61231, Germany; Max Planck Institute for Heart and Lung Research, Biomolecular Mass Spectrometry, Bad Nauheim, 61231, Germany
| | - Didier Y R Stainier
- Max Planck Institute for Heart and Lung Research, Department of Developmental Genetics, Bad Nauheim, 61231, Germany.
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Barbosa P, Zhaunova L, Debilio S, Steccanella V, Kelly V, Ly T, Ohkura H. SCF-Fbxo42 promotes synaptonemal complex assembly by downregulating PP2A-B56. J Cell Biol 2020; 220:211645. [PMID: 33382409 PMCID: PMC7780726 DOI: 10.1083/jcb.202009167] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 11/20/2020] [Accepted: 12/02/2020] [Indexed: 12/27/2022] Open
Abstract
Meiosis creates genetic diversity by recombination and segregation of chromosomes. The synaptonemal complex assembles during meiotic prophase I and assists faithful exchanges between homologous chromosomes, but how its assembly/disassembly is regulated remains to be understood. Here, we report how two major posttranslational modifications, phosphorylation and ubiquitination, cooperate to promote synaptonemal complex assembly. We found that the ubiquitin ligase complex SCF is important for assembly and maintenance of the synaptonemal complex in Drosophila female meiosis. This function of SCF is mediated by two substrate-recognizing F-box proteins, Slmb/βTrcp and Fbxo42. SCF-Fbxo42 down-regulates the phosphatase subunit PP2A-B56, which is important for synaptonemal complex assembly and maintenance.
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Affiliation(s)
- Pedro Barbosa
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Liudmila Zhaunova
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Simona Debilio
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK,Department of Biology and Biotechnology, University of Pavia, Pavia, Italy
| | - Verdiana Steccanella
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Van Kelly
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Tony Ly
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Hiroyuki Ohkura
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK,Correspondence to Hiroyuki Ohkura:
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Abstract
Background The formation of matured and individual sperm involves a series of molecular and spectacular morphological changes of the developing cysts in Drosophila melanogaster testis. Recent advances in RNA Sequencing (RNA-Seq) technology help us to understand the complexity of eukaryotic transcriptomes by dissecting different tissues and developmental stages of organisms. To gain a better understanding of cellular differentiation of spermatogenesis, we applied RNA-Seq to analyse the testis-specific transcriptome, including coding and non-coding genes. Results We isolated three different parts of the wild-type testis by dissecting and cutting the different regions: 1.) the apical region, which contains stem cells and developing spermatocytes 2.) the middle region, with enrichment of meiotic cysts 3.) the basal region, which contains elongated post-meiotic cysts with spermatids. Total RNA was isolated from each region and analysed by next-generation sequencing. We collected data from the annotated 17412 Drosophila genes and identified 5381 genes with significant transcript accumulation differences between the regions, representing the main stages of spermatogenesis. We demonstrated for the first time the presence and region specific distribution of 2061 lncRNAs in testis, with 203 significant differences. Using the available modENCODE RNA-Seq data, we determined the tissue specificity indices of Drosophila genes. Combining the indices with our results, we identified genes with region-specific enrichment in testis. Conclusion By multiple analyses of our results and integrating existing knowledge about Drosophila melanogaster spermatogenesis to our dataset, we were able to describe transcript composition of different regions of Drosophila testis, including several stage-specific transcripts. We present searchable visualizations that can facilitate the identification of new components that play role in the organisation and composition of different stages of spermatogenesis, including the less known, but complex regulation of post-meiotic stages. Electronic supplementary material The online version of this article (10.1186/s12864-018-5085-z) contains supplementary material, which is available to authorized users.
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Zhang JS, Li XJ, Yang L, Li WW, Wang Q. Expression pattern and functional analysis of the two RING box protein RBX in spermatogenesis of Chinese mitten crab Eriocheir sinensis. Gene 2018; 668:237-245. [PMID: 29775751 DOI: 10.1016/j.gene.2018.05.026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 05/05/2018] [Accepted: 05/08/2018] [Indexed: 11/27/2022]
Abstract
Studies in E. sinensis have shown that ubiquitination mediated by Cullin-RING E3 ligases (CRLs) plays important roles in spermatogenesis. In other species, CRLs are also essential in cell cycle progression, DNA replication, signal transduction, gene transcription, and development. The catalytic RING component, the RING box protein, is an important part of CRLs. However, there have been few studies on CRLs in crustaceans. In this study, we cloned two RING box protein genes from the Chinese mitten crab, Eriocheir sinensis, termed Es-RBX1 and Es-RBX2 The full length Es-RBX1 cDNA comprises 741 nucleotides, and encodes a protein of 124 amino acid residues, whereas the Es-RBX2 cDNA comprises 1325 nucleotides, and encodes a protein of 110 amino acid residues. Bioinformatics analysis showed that the domains and structure of the RBX proteins have been highly conserved during evolution. Quantitative real-time polymerase chain reaction and western blotting showed that Es-RBX1 is highly expressed in the testis, particularly during the spermatocyte stage, whereas Es-RBX2 did not show specific expression in the male reproductive system. Furthermore, Es-RBX1 is mainly distributed in the nucleus, and changed its location with the development of the nucleus. Co-immunoprecipitation showed that Es-RBX1 could bind Cullin4. These results suggested that Es-RBX1 plays a key role in spermatogenesis of E. sinensis though forming a complex with Cullin4.
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Affiliation(s)
- Jia-Shun Zhang
- Laboratory of Invertebrate Immunological Defense & Reproductive Biology, School of Life Science, East China Normal University, Shanghai, China
| | - Xue-Jie Li
- Laboratory of Invertebrate Immunological Defense & Reproductive Biology, School of Life Science, East China Normal University, Shanghai, China
| | - Lei Yang
- Laboratory of Invertebrate Immunological Defense & Reproductive Biology, School of Life Science, East China Normal University, Shanghai, China
| | - Wei-Wei Li
- Laboratory of Invertebrate Immunological Defense & Reproductive Biology, School of Life Science, East China Normal University, Shanghai, China
| | - Qun Wang
- Laboratory of Invertebrate Immunological Defense & Reproductive Biology, School of Life Science, East China Normal University, Shanghai, China.
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Hao YJ, Zhang YJ, Si FL, Fu DY, He ZB, Chen B. Insight into the possible mechanism of the summer diapause of Delia antiqua (Diptera: Anthomyiidae) through digital gene expression analysis. INSECT SCIENCE 2016; 23:438-51. [PMID: 26826557 DOI: 10.1111/1744-7917.12323] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Revised: 01/12/2016] [Accepted: 01/24/2016] [Indexed: 05/20/2023]
Abstract
The onion fly, Delia antiqua, is a major underground agricultural pest that can enter pupal diapause in the summer and winter seasons. However, little is known about its molecular regulation due to the lack of genomic resources. To gain insight into the possible mechanism of summer diapause (SD), high-throughput RNA-Seq data were generated from non-diapause (ND) and SD (initial, maintenance and quiescence phase) pupae. Three pair-wise comparisons were performed and identified, 1380, 1471 and 435, and were significantly regulated transcripts. Further analysis revealed that the enrichment of several functional terms related to juvenile hormone regulation, cell cycle, carbon hydrate and lipid metabolism, innate immune and stress responses, various signalling transductions, ubiquitin-dependent proteosome, and variation in cuticular and cytoskeleton components were found between ND and SD and between different phases of SD. Global characterization of transcriptome profiling between SD and ND contributes to the in-depth elucidation of the molecular mechanism of SD. Our results also offer insights into the evolution of insect diapause and support the importance of using the onion fly as a model to compare the molecular regulation events of summer and winter diapauses.
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Affiliation(s)
| | | | - Feng-Ling Si
- Institute of Entomology and Molecular Biology, College of Life Sciences, Chongqing Normal University, Chongqing, China
| | - Dan-Ying Fu
- Institute of Entomology and Molecular Biology, College of Life Sciences, Chongqing Normal University, Chongqing, China
| | - Zheng-Bo He
- Institute of Entomology and Molecular Biology, College of Life Sciences, Chongqing Normal University, Chongqing, China
| | - Bin Chen
- Institute of Entomology and Molecular Biology, College of Life Sciences, Chongqing Normal University, Chongqing, China
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6
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Wong JJL, Li S, Lim EKH, Wang Y, Wang C, Zhang H, Kirilly D, Wu C, Liou YC, Wang H, Yu F. A Cullin1-based SCF E3 ubiquitin ligase targets the InR/PI3K/TOR pathway to regulate neuronal pruning. PLoS Biol 2013; 11:e1001657. [PMID: 24068890 PMCID: PMC3775723 DOI: 10.1371/journal.pbio.1001657] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Accepted: 08/08/2013] [Indexed: 11/19/2022] Open
Abstract
Pruning that selectively eliminates unnecessary axons/dendrites is crucial for sculpting the nervous system during development. During Drosophila metamorphosis, dendrite arborization neurons, ddaCs, selectively prune their larval dendrites in response to the steroid hormone ecdysone, whereas mushroom body γ neurons specifically eliminate their axon branches within dorsal and medial lobes. However, it is unknown which E3 ligase directs these two modes of pruning. Here, we identified a conserved SCF E3 ubiquitin ligase that plays a critical role in pruning of both ddaC dendrites and mushroom body γ axons. The SCF E3 ligase consists of four core components Cullin1/Roc1a/SkpA/Slimb and promotes ddaC dendrite pruning downstream of EcR-B1 and Sox14, but independently of Mical. Moreover, we demonstrate that the Cullin1-based E3 ligase facilitates ddaC dendrite pruning primarily through inactivation of the InR/PI3K/TOR pathway. We show that the F-box protein Slimb forms a complex with Akt, an activator of the InR/PI3K/TOR pathway, and promotes Akt ubiquitination. Activation of the InR/PI3K/TOR pathway is sufficient to inhibit ddaC dendrite pruning. Thus, our findings provide a novel link between the E3 ligase and the InR/PI3K/TOR pathway during dendrite pruning.
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Affiliation(s)
- Jack Jing Lin Wong
- Temasek Life Sciences Laboratory and Department of Biological Sciences, National University of Singapore, Singapore
- Graduate School for Integrated Sciences and Engineering, Centre for Life Sciences, National University of Singapore (NUS), Singapore
| | - Song Li
- Graduate School for Integrated Sciences and Engineering, Centre for Life Sciences, National University of Singapore (NUS), Singapore
- Neuroscience and Behavioral Disorder Program, Duke–NUS Graduate Medical School Singapore, Singapore
| | - Edwin Kok Hao Lim
- Temasek Life Sciences Laboratory and Department of Biological Sciences, National University of Singapore, Singapore
| | - Yan Wang
- Temasek Life Sciences Laboratory and Department of Biological Sciences, National University of Singapore, Singapore
| | - Cheng Wang
- Neuroscience and Behavioral Disorder Program, Duke–NUS Graduate Medical School Singapore, Singapore
| | - Heng Zhang
- Temasek Life Sciences Laboratory and Department of Biological Sciences, National University of Singapore, Singapore
| | - Daniel Kirilly
- Temasek Life Sciences Laboratory and Department of Biological Sciences, National University of Singapore, Singapore
| | - Chunlai Wu
- Neuroscience Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, Louisiana, United States of America
| | - Yih-Cherng Liou
- Temasek Life Sciences Laboratory and Department of Biological Sciences, National University of Singapore, Singapore
- Graduate School for Integrated Sciences and Engineering, Centre for Life Sciences, National University of Singapore (NUS), Singapore
| | - Hongyan Wang
- Graduate School for Integrated Sciences and Engineering, Centre for Life Sciences, National University of Singapore (NUS), Singapore
- Neuroscience and Behavioral Disorder Program, Duke–NUS Graduate Medical School Singapore, Singapore
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Fengwei Yu
- Temasek Life Sciences Laboratory and Department of Biological Sciences, National University of Singapore, Singapore
- Graduate School for Integrated Sciences and Engineering, Centre for Life Sciences, National University of Singapore (NUS), Singapore
- Neuroscience and Behavioral Disorder Program, Duke–NUS Graduate Medical School Singapore, Singapore
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
- * E-mail:
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7
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Zhang Z, Lv X, Yin WC, Zhang X, Feng J, Wu W, Hui CC, Zhang L, Zhao Y. Ter94 ATPase complex targets k11-linked ubiquitinated ci to proteasomes for partial degradation. Dev Cell 2013; 25:636-44. [PMID: 23747190 DOI: 10.1016/j.devcel.2013.05.006] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2012] [Revised: 04/09/2013] [Accepted: 05/03/2013] [Indexed: 12/24/2022]
Abstract
The Cubitus interruptus (Ci)/Gli family of transcription factors can be degraded either completely or partially from a full-length form (Ci155/Gli(FL)) to a truncated repressor (Ci75/Gli(R)) by proteasomes to mediate Hedgehog (Hh) signaling. The mechanism by which proteasomes distinguish ubiquitinated Ci/Gli to carry out complete versus partial degradation is not known. Here, we show that Ter94 ATPase and its mammalian counterpart, p97, are involved in processing Ci and Gli3 into Ci75 and Gli3(R), respectively. Ter94 regulates the partial degradation of ubiquitinated Ci by Cul1-Slimb-based E3 ligase through its adaptors Ufd1-like and dNpl4. We demonstrate that Cul1-Slimb-based E3 ligase, but not Cul3-Rdx-based E3 ligase, modifies Ci by efficient addition of K11-linked ubiquitin chains. Ter94(Ufd1-like/dNpl4) complex interacts directly with Cul1-Slimb, and, intriguingly, it prefers K11-linked ubiquitinated Ci. Thus, Ter94 ATPase and K11-linked ubiquitination in Ci contribute to the selectivity by proteasomes for partial degradation.
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Affiliation(s)
- Zhao Zhang
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
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8
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Stanley DJ, Bartholomeeusen K, Crosby DC, Kim DY, Kwon E, Yen L, Cartozo NC, Li M, Jäger S, Mason-Herr J, Hayashi F, Yokoyama S, Krogan NJ, Harris RS, Peterlin BM, Gross JD. Inhibition of a NEDD8 Cascade Restores Restriction of HIV by APOBEC3G. PLoS Pathog 2012; 8:e1003085. [PMID: 23300442 PMCID: PMC3531493 DOI: 10.1371/journal.ppat.1003085] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2012] [Accepted: 10/30/2012] [Indexed: 01/18/2023] Open
Abstract
Cellular restriction factors help to defend humans against human immunodeficiency virus (HIV). HIV accessory proteins hijack at least three different Cullin-RING ubiquitin ligases, which must be activated by the small ubiquitin-like protein NEDD8, in order to counteract host cellular restriction factors. We found that conjugation of NEDD8 to Cullin-5 by the NEDD8-conjugating enzyme UBE2F is required for HIV Vif-mediated degradation of the host restriction factor APOBEC3G (A3G). Pharmacological inhibition of the NEDD8 E1 by MLN4924 or knockdown of either UBE2F or its RING-protein binding partner RBX2 bypasses the effect of Vif, restoring the restriction of HIV by A3G. NMR mapping and mutational analyses define specificity determinants of the UBE2F NEDD8 cascade. These studies demonstrate that disrupting host NEDD8 cascades presents a novel antiretroviral therapeutic approach enhancing the ability of the immune system to combat HIV.
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Affiliation(s)
- David J. Stanley
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California, United States of America
- Graduate Program in Biophysics, University of California, San Francisco, San Francisco, California, United States of America
| | - Koen Bartholomeeusen
- Department of Medicine, University of California, San Francisco, San Francisco, California, United States of America
| | - David C. Crosby
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, California, United States of America
| | - Dong Young Kim
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California, United States of America
| | - Eunju Kwon
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California, United States of America
| | - Linda Yen
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California, United States of America
| | - Nathalie Caretta Cartozo
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California, United States of America
| | - Ming Li
- Department of Biochemistry, Molecular Biology and Biophysics, Institute for Molecular Virology, Center for Genome Engineering, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Stefanie Jäger
- Department of Molecular and Cellular Pharmacology, University of California, San Francisco, San Francisco, California, United States of America
| | - Jeremy Mason-Herr
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California, United States of America
| | - Fumiaki Hayashi
- RIKEN Systems and Structural Biology Center, Tsurumi, Yokohama, Japan
| | - Shigeyuki Yokoyama
- RIKEN Systems and Structural Biology Center, Tsurumi, Yokohama, Japan
- Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, Japan
| | - Nevan J. Krogan
- Department of Molecular and Cellular Pharmacology, University of California, San Francisco, San Francisco, California, United States of America
- California Institute for Quantitative Biosciences, QB3, University of California, San Francisco, San Francisco, California, United States of America
- J. David Gladstone Institutes, San Francisco, California, United States of America
| | - Reuben S. Harris
- Department of Biochemistry, Molecular Biology and Biophysics, Institute for Molecular Virology, Center for Genome Engineering, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Boris Matija Peterlin
- Department of Medicine, University of California, San Francisco, San Francisco, California, United States of America
| | - John D. Gross
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California, United States of America
- California Institute for Quantitative Biosciences, QB3, University of California, San Francisco, San Francisco, California, United States of America
- * E-mail:
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9
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Pan Y, Xu H, Liu R, Jia L. Induction of cell senescence by targeting to Cullin-RING Ligases (CRLs) for effective cancer therapy. INTERNATIONAL JOURNAL OF BIOCHEMISTRY AND MOLECULAR BIOLOGY 2012; 3:273-281. [PMID: 23097743 PMCID: PMC3476791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 07/22/2012] [Accepted: 09/17/2012] [Indexed: 06/01/2023]
Abstract
Cullin-RING ligases (CRLs) are the biggest family of multiunit ubiquitin E3 ligases, controlling many biological processes by promoting the degradation of a broad spectrum of proteins associated with cell cycle, signal transduction and cell growth. The dysfunction of CRLs causes a lot of diseases including cancer, which meanwhile offers us a promising approach to cancer therapy by targeting to CRLs. Recent studies have demonstrated that genetic or pharmaceutical inactivation of CRLs often leads to cancer cell death by activating multiple cell-killing pathways including senescence, an emerging anticancer mechanism of therapeutic agents. Here, we summarize the induction of cellular senescence and its mechanism of action, triggered by targeting to specific subunits of CRLs via multiple approaches including siRNA silencing, genetic knockout as well as small molecule inhibitor, exhibiting anticancer effect in vitro and in vivo.
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Affiliation(s)
- Yongfu Pan
- Department of Immunology, Shanghai Medical College, Fudan UniversityShanghai 200032, China
| | - Hua Xu
- Department of Immunology, Shanghai Medical College, Fudan UniversityShanghai 200032, China
| | - Rujiao Liu
- Department of Immunology, Shanghai Medical College, Fudan UniversityShanghai 200032, China
| | - Lijun Jia
- Department of Immunology, Shanghai Medical College, Fudan UniversityShanghai 200032, China
- Biotherapy Research Center of Fudan UniversityShanghai 200032, China
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10
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Sloan RS, Swanson CI, Gavilano L, Smith KN, Malek PY, Snow-Smith M, Duronio RJ, Key SCS. Characterization of null and hypomorphic alleles of the Drosophila l(2)dtl/cdt2 gene: Larval lethality and male fertility. Fly (Austin) 2012; 6:173-83. [PMID: 22722696 DOI: 10.4161/fly.20247] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The Drosophila lethal(2)denticleless (l(2)dtl) gene was originally reported as essential for embryogenesis and formation of the rows of tiny hairs on the larval ventral cuticle known as denticle belts. It is now well-established that l(2)dtl (also called cdt2) encodes a subunit of a Cullin 4-based E3 ubiquitin ligase complex that targets a number of key cell cycle regulatory proteins, including p21, Cdt1, E2F1 and Set8, to prevent replication defects and maintain cell cycle control. To investigate the role of l(2)dtl/cdt2 during development, we characterized existing l(2)dtl/cdt2 mutants and generated new deletion alleles, using P-element excision mutagenesis. Surprisingly, homozygous l(2)dtl/cdt2 mutant embryos developed beyond embryogenesis, had intact denticle belts, and lacked an observable embryonic replication defect. These mutants died during larval stages, affirming that loss of l(2)dtl/cdt2 function is lethal. Our data show that L(2)dtl/Cdt2 is maternally deposited, remains nuclear throughout the cell cycle, and has a previously unreported, elevated expression in the developing gonads. We also find that E2f1 regulates l(2)dtl/cdt2 expression during embryogenesis, possibly via several highly conserved putative E2f1 binding sites near the l(2)dtl/cdt2 promoter. Finally, hypomorphic allele combinations of the l(2)dtl/cdt2 gene result in a novel phenotype: viable, low-fertility males. We conclude that "denticleless" is a misnomer, but that l(2)dtl/cdt2 is an essential gene for Drosophila development.
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Affiliation(s)
- Roketa S Sloan
- Department of Biology, North Carolina Central University, Durham, NC USA
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11
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Roberts DM, Pronobis MI, Alexandre KM, Rogers GC, Poulton JS, Schneider DE, Jung KC, McKay DJ, Peifer M. Defining components of the ß-catenin destruction complex and exploring its regulation and mechanisms of action during development. PLoS One 2012; 7:e31284. [PMID: 22359584 PMCID: PMC3281067 DOI: 10.1371/journal.pone.0031284] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2011] [Accepted: 01/05/2012] [Indexed: 11/19/2022] Open
Abstract
Background A subset of signaling pathways play exceptionally important roles in embryonic and post-embryonic development, and mis-regulation of these pathways occurs in most human cancers. One such pathway is the Wnt pathway. The primary mechanism keeping Wnt signaling off in the absence of ligand is regulated proteasomal destruction of the canonical Wnt effector ßcatenin (or its fly homolog Armadillo). A substantial body of evidence indicates that SCFβTrCP mediates βcat destruction, however, an essential role for Roc1 has not been demonstrated in this process, as would be predicted. In addition, other E3 ligases have also been proposed to destroy βcat, suggesting that βcat destruction may be regulated differently in different tissues. Methodology/Principal Findings Here we used cultured Drosophila cells, human colon cancer cells, and Drosophila embryos and larvae to explore the machinery that targets Armadillo for destruction. Using RNAi in Drosophila S2 cells to examine which SCF components are essential for Armadillo destruction, we find that Roc1/Roc1a is essential for regulating Armadillo stability, and that in these cells the only F-box protein playing a detectable role is Slimb. Second, we find that while embryonic and larval Drosophila tissues use the same destruction complex proteins, the response of these tissues to destruction complex inactivation differs, with Armadillo levels more elevated in embryos. We provide evidence consistent with the possibility that this is due to differences in armadillo mRNA levels. Third, we find that there is no correlation between the ability of different APC2 mutant proteins to negatively regulate Armadillo levels, and their recently described function in positively-regulating Wnt signaling. Finally, we demonstrate that APC proteins lacking the N-terminal Armadillo-repeat domain cannot restore Armadillo destruction but retain residual function in negatively-regulating Wnt signaling. Conclusions/Significance We use these data to refine our model for how Wnt signaling is regulated during normal development.
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Affiliation(s)
- David M. Roberts
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- Department of Biology, Franklin and Marshall College, Lancaster, Pennsylvania, United States of America
- * E-mail: (DMR); (MP)
| | - Mira I. Pronobis
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Kelly M. Alexandre
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Gregory C. Rogers
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, Arizona, United States of America
| | - John S. Poulton
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Daniel E. Schneider
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Kuo-Chen Jung
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Daniel J. McKay
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Mark Peifer
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- * E-mail: (DMR); (MP)
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12
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Rohn JL, Sims D, Liu T, Fedorova M, Schöck F, Dopie J, Vartiainen MK, Kiger AA, Perrimon N, Baum B. Comparative RNAi screening identifies a conserved core metazoan actinome by phenotype. ACTA ACUST UNITED AC 2012; 194:789-805. [PMID: 21893601 PMCID: PMC3171124 DOI: 10.1083/jcb.201103168] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
RNAi screens in Drosophila and human cells for novel actin
regulators revealed conserved roles for proteins involved in nuclear actin
export, RNA splicing, and ubiquitination. Although a large number of actin-binding proteins and their regulators have been
identified through classical approaches, gaps in our knowledge remain. Here, we
used genome-wide RNA interference as a systematic method to define metazoan
actin regulators based on visual phenotype. Using comparative screens in
cultured Drosophila and human cells, we generated phenotypic
profiles for annotated actin regulators together with proteins bearing predicted
actin-binding domains. These phenotypic clusters for the known metazoan
“actinome” were used to identify putative new core actin
regulators, together with a number of genes with conserved but poorly studied
roles in the regulation of the actin cytoskeleton, several of which we studied
in detail. This work suggests that although our search for new components of the
core actin machinery is nearing saturation, regulation at the level of nuclear
actin export, RNA splicing, ubiquitination, and other upstream processes remains
an important but unexplored frontier of actin biology.
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Affiliation(s)
- Jennifer L Rohn
- MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, England, UK.
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13
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SAG/RBX2/ROC2 E3 ubiquitin ligase is essential for vascular and neural development by targeting NF1 for degradation. Dev Cell 2011; 21:1062-76. [PMID: 22118770 DOI: 10.1016/j.devcel.2011.09.014] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2010] [Revised: 06/09/2011] [Accepted: 09/26/2011] [Indexed: 11/21/2022]
Abstract
SAG/RBX2/ROC2 protein is an essential RING component of SCF E3 ubiquitin ligase. The role of SAG during embryogenesis remains unknown. We report a critical role for SAG in controlling vascular and neural development by modulating RAS activity via promoting degradation of neurofibromatosis type 1 (NF1). Mice mutant for Sag died at embryonic day 11.5-12.5 with severe abnormalities in vascular and nervous system. Sag inactivation caused Nf1 accumulation and Ras inhibition, which blocks embryonic stem (ES) cells from undergoing endothelial differentiation and inhibits angiogenesis and proliferation in teratomas. Simultaneous Nf1 deletion fully rescues the differentiation defects in Sag(-/-) ES cells and partially rescues vascular and neural defects in Sag(-/-) embryos, suggesting that the effects of Sag deletion may not be solely explained by Nf1 misregulation. Collectively, our study identifies NF1 as a physiological substrate of SAG-CUL1-FBXW7 E3 ligase and establishes a ubiquitin-dependent regulatory mechanism for the NF1-RAS pathway during embryogenesis.
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Gradients of a Ubiquitin E3 Ligase Inhibitor and a Caspase Inhibitor Determine Differentiation or Death in Spermatids. Dev Cell 2010; 19:160-73. [DOI: 10.1016/j.devcel.2010.06.009] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Revised: 03/25/2010] [Accepted: 05/04/2010] [Indexed: 11/21/2022]
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15
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Wei D, Sun Y. Small RING Finger Proteins RBX1 and RBX2 of SCF E3 Ubiquitin Ligases: The Role in Cancer and as Cancer Targets. Genes Cancer 2010; 1:700-7. [PMID: 21103004 PMCID: PMC2983490 DOI: 10.1177/1947601910382776] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The SCF (Skp1-cullin-F-box proteins), also known as CRL (cullin-based RING ligase), is the largest family of E3 ubiquitin ligases that mediate approximately 20% ubiquitinated protein substrates for 26S proteasome degradation. Through promoting timely degradation of many key regulatory proteins, SCF E3 ligase controls numerous cellular processes; its dysfunction contributes to a number of human diseases, including cancer. The RING component of SCF complex consists of 2 family members, RBX1 (RING box protein 1), also known as ROC1 (regulator of cullins), and RBX2/ROC2 (also known as SAG [sensitive to apoptosis gene]), both of which are essential for the catalytic activity of SCF. RBX1 and RBX2 are evolutionarily conserved from yeast to humans and play an essential role during mouse embryonic development. Moreover, RBX1 and RBX2 are both overexpressed in multiple human cancer tissues and required for the growth and survival of cancer cells. In this review, we will discuss the similarities and differences between 2 RING family members, their regulation of SCF E3 ligase activity, and their role in development, cancer cell survival, and skin carcinogenesis, along with a brief discussion of RBX-SCF E3 ligases as the cancer targets and a recently discovered small molecule inhibitor of SCF E3 ligases as a novel class of anticancer drugs.
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Affiliation(s)
- Dongping Wei
- Division of Radiation and Cancer Biology, Department of Radiation Oncology, University of Michigan Comprehensive Cancer Center, Ann Arbor, MI, USA
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16
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Jia L, Sun Y. RBX1/ROC1-SCF E3 ubiquitin ligase is required for mouse embryogenesis and cancer cell survival. Cell Div 2009; 4:16. [PMID: 19660140 PMCID: PMC2732615 DOI: 10.1186/1747-1028-4-16] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2009] [Accepted: 08/06/2009] [Indexed: 12/17/2022] Open
Abstract
RBX1 (also known as ROC1) is a RING subunit of SCF (Skp1, Cullins, F-box proteins) E3 ubiquitin ligases, required for SCF to direct a timely degradation of diverse substrates, thereby regulating numerous cellular processes under both physiological and pathological conditions. Previous studies have shown that RBX1 is essential for growth in yeast, Caenorhabditis elegans and Drosophila. The role of RBX1 in mouse development and in regulation of cancer cell survival was unknown. Our recent work demonstrated that RBX1 is an essential gene for mouse embryogenesis, and targeted disruption of RBX1 causes embryonic lethality at E7.5 due to hypoproliferation as a result of p27 accumulation. We also showed that RBX1 is overexpressed in a number of human cancers, and siRNA silencing of RBX1 caused cancer cell death as a result of sequential induction of G2-M arrest, senescence and apoptosis. These findings reveal a physiological role of RBX1 during mouse development and a pathological role for the survival of human cancer cells. Differential outcomes between normal (growth arrest) and cancer cells (cell death) upon RBX1 disruption/silencing suggest RBX1 as a valid anticancer target. Comments on: Tan M, Davis SW, Saunders TL, Zhu Y, Sun Y. RBX1/ROC1 disruption results in early embryonic lethality due to proliferation failure, partially rescued by simultaneous loss of p27. Proc Natl Acad Sci USA. 2009; 106:6203–6208 Jia L, Soengas MS, Sun Y. ROC1/RBX1 E3 ubiquitin ligase silencing suppresses tumor cell growth via sequential induction of G2-M arrest, apoptosis, and senescence. Cancer Res. 2009; 69:4974–82
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Affiliation(s)
- Lijun Jia
- Division of Radiation and Cancer Biology, Department of Radiation Oncology, University of Michigan Comprehensive Cancer Center, 4424B Medical Science-I, 1301 Catherine Street, Ann Arbor, MI 48109, USA.
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17
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RBX1/ROC1 disruption results in early embryonic lethality due to proliferation failure, partially rescued by simultaneous loss of p27. Proc Natl Acad Sci U S A 2009; 106:6203-8. [PMID: 19325126 DOI: 10.1073/pnas.0812425106] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
RBX1 (RING box protein-1) or ROC1 (regulator of cullins-1) is the RING component of SCF (Skp1, Cullins, F-box proteins) E3 ubiquitin ligases, which regulate diverse cellular processes by targeting various substrates for degradation. However, the in vivo physiological function of RBX1 remains uncharacterized. Here, we show that a gene trap disruption of mouse Rbx1 causes embryonic lethality at embryonic day (E)7.5, mainly due to a failure in proliferation; p27, a cyclin dependent kinase inhibitor, normally undetectable in the early embryos, accumulates at high levels in the absence of Rbx1. Although mice heterozygous for the Rbx1 gene trap appear viable and fertile without obvious abnormalities, the Rbx1(+/Gt) MEFs do show retarded growth with G1 arrest and p27 accumulation. Simultaneous loss of p27 extended the life span of Rbx1(Gt/Gt) embryos from E6.5 to E9.5, indicating that p27-mediated cell cycle inhibition contributes to the early embryonic lethality in the Rbx1-deficient embryos. Our study demonstrates that the in vivo physiological function of RBX1 is to ensure cell proliferation by preventing p27 accumulation during the early stage of embryonic development.
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18
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Reynolds PJ, Simms JR, Duronio RJ. Identifying determinants of cullin binding specificity among the three functionally different Drosophila melanogaster Roc proteins via domain swapping. PLoS One 2008; 3:e2918. [PMID: 18698375 PMCID: PMC2500221 DOI: 10.1371/journal.pone.0002918] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2008] [Accepted: 07/12/2008] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Cullin-dependent E3 ubiquitin ligases (CDL) are key regulators of protein destruction that participate in a wide range of cell biological processes. The Roc subunit of CDL contains an evolutionarily conserved RING domain that binds ubiquitin charged E2 and is essential for ubiquitylation. Drosophila melanogaster contains three highly related Roc proteins: Roc1a and Roc2, which are conserved in vertebrates, and Roc1b, which is specific to Drosophila. Our previous genetic data analyzing Roc1a and Roc1b mutants suggested that Roc proteins are functionally distinct, but the molecular basis for this distinction is not known. METHODOLOGY/PRINCIPAL FINDINGS Using co-immunoprecipitation studies we show that Drosophila Roc proteins bind specific Cullins: Roc1a binds Cul1-4, Roc1b binds Cul3, and Roc2 binds Cul5. Through domain swapping experiments, we demonstrate that Cullin binding specificity is strongly influenced by the Roc NH(2)-terminal domain, which forms an inter-molecular beta sheet with the Cullin. Substitution of the Roc1a RING domain with that of Roc1b results in a protein with similar Cullin binding properties to Roc1a that is active as an E3 ligase but cannot complement Roc1a mutant lethality, indicating that the identity of the RING domain can be an important determinant of CDL function. In contrast, the converse chimeric protein with a substitution of the Roc1b RING domain with that of Roc1a can rescue the male sterility of Roc1b mutants, but only when expressed from the endogenous Roc1b promoter. We also identified mutations of Roc2 and Cul5 and show that they cause no overt developmental phenotype, consistent with our finding that Roc2 and Cul5 proteins are exclusive binding partners, which others have observed in human cells as well. CONCLUSIONS The Drosophila Roc proteins are highly similar, but have diverged during evolution to bind a distinct set of Cullins and to utilize RING domains that have overlapping, but not identical, function in vivo.
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Affiliation(s)
- Patrick J. Reynolds
- Department of Biology, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Jeffrey R. Simms
- Program in Molecular Biology and Biotechnology, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Robert J. Duronio
- Department of Biology, University of North Carolina, Chapel Hill, North Carolina, United States of America
- Program in Molecular Biology and Biotechnology, University of North Carolina, Chapel Hill, North Carolina, United States of America
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina, United States of America
- * E-mail:
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19
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Bai Y, Casola C, Betrán E. Evolutionary origin of regulatory regions of retrogenes in Drosophila. BMC Genomics 2008; 9:241. [PMID: 18498650 PMCID: PMC2413143 DOI: 10.1186/1471-2164-9-241] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2008] [Accepted: 05/22/2008] [Indexed: 12/29/2022] Open
Abstract
Background Retrogenes are processed copies of other genes. This duplication mechanism produces a copy of the parental gene that should not contain introns, and usually does not contain cis-regulatory regions. Here, we computationally address the evolutionary origin of promoter and other cis-regulatory regions in retrogenes using a total of 94 Drosophila retroposition events we recently identified. Previous tissue expression data has revealed that a large fraction of these retrogenes are specifically and/or highly expressed in adult testes of Drosophila. Results In this work, we infer that retrogenes do not generally carry regulatory regions from aberrant upstream or normal transcripts of their parental genes, and that expression patterns of neighboring genes are not consistently shared by retrogenes. Additionally, transposable elements do not appear to substantially provide regulatory regions to retrogenes. Interestingly, we find that there is an excess of retrogenes in male testis neighborhoods that is not explained by insertional biases of the retroelement machinery used for retroposition. Conclusion We conclude that retrogenes' regulatory regions mostly do not represent a random set of existing regulatory regions. On the contrary, our conclusion is that selection is likely to have played an important role in the persistence of autosomal testis biased retrogenes. Selection in favor of retrogenes inserted in male testis neighborhoods and at the sequence level to produce testis expression is postulated to have occurred.
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Affiliation(s)
- Yongsheng Bai
- Department of Biology, University of Texas at Arlington, Arlington, TX, USA.
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20
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Abstract
We present detailed protocols for two methods of gene targeting in Drosophila. The first, ends-out targeting, is identical in concept to gene replacement techniques used routinely in mammalian and yeast cells. In Drosophila, the targeted gene is replaced by the marker gene white + (although options exist to generate unmarked targeted alleles). This approach is simple in both the molecular cloning and the genetic manipulations. Ends-out will likely serve most investigators' purposes to generate simple gene deletions or reporter gene "knock-ins." The second method, ends-in targeting, targets a wild-type gene with an engineered mutated copy and generates a duplication structure at the target locus. This duplication can subsequently be reduced to one copy, removing the wild-type gene and leaving only the introduced mutation. Although more complicated in the cloning and genetic manipulations (see Note 1), this approach has the benefit that the mutations may be introduced with no other remnant of the targeting procedure. This "surgical" approach will appeal to investigators who desire minimal perturbation to the genome, such as single nucleotide mutation. Although both approaches appear to be approximately equally efficient (see Note 2), each method has separate strengths and drawbacks. The choice of which approach is best depends on the researcher's goal.
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Affiliation(s)
- Keith A Maggert
- Department of Biology, Texas A&M University, College Station, TX, USA
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21
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Arama E, Bader M, Rieckhof GE, Steller H. A ubiquitin ligase complex regulates caspase activation during sperm differentiation in Drosophila. PLoS Biol 2007; 5:e251. [PMID: 17880263 PMCID: PMC1976628 DOI: 10.1371/journal.pbio.0050251] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2007] [Accepted: 07/25/2007] [Indexed: 11/19/2022] Open
Abstract
In both insects and mammals, spermatids eliminate their bulk cytoplasm as they undergo terminal differentiation. In Drosophila, this process of dramatic cellular remodeling requires apoptotic proteins, including caspases. To gain further insight into the regulation of caspases, we screened a large collection of sterile male flies for mutants that block effector caspase activation at the onset of spermatid individualization. Here, we describe the identification and characterization of a testis-specific, Cullin-3-dependent ubiquitin ligase complex that is required for caspase activation in spermatids. Mutations in either a testis-specific isoform of Cullin-3 (Cul3(Testis)), the small RING protein Roc1b, or a Drosophila orthologue of the mammalian BTB-Kelch protein Klhl10 all reduce or eliminate effector caspase activation in spermatids. Importantly, all three genes encode proteins that can physically interact to form a ubiquitin ligase complex. Roc1b binds to the catalytic core of Cullin-3, and Klhl10 binds specifically to a unique testis-specific N-terminal Cullin-3 (TeNC) domain of Cul3(Testis) that is required for activation of effector caspase in spermatids. Finally, the BIR domain region of the giant inhibitor of apoptosis-like protein dBruce is sufficient to bind to Klhl10, which is consistent with the idea that dBruce is a substrate for the Cullin-3-based E3-ligase complex. These findings reveal a novel role of Cullin-based ubiquitin ligases in caspase regulation.
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Affiliation(s)
- Eli Arama
- Strang Laboratory of Cancer Research, The Rockefeller University, New York, New York, United States of America
- Howard Hughes Medical Institute, The Rockefeller University, New York, New York, United States of America
| | - Maya Bader
- Strang Laboratory of Cancer Research, The Rockefeller University, New York, New York, United States of America
- Howard Hughes Medical Institute, The Rockefeller University, New York, New York, United States of America
| | - Gabrielle E Rieckhof
- Strang Laboratory of Cancer Research, The Rockefeller University, New York, New York, United States of America
- Howard Hughes Medical Institute, The Rockefeller University, New York, New York, United States of America
| | - Hermann Steller
- Strang Laboratory of Cancer Research, The Rockefeller University, New York, New York, United States of America
- Howard Hughes Medical Institute, The Rockefeller University, New York, New York, United States of America
- * To whom correspondence should be addressed. E-mail:
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O'Keefe LV, Smibert P, Colella A, Chataway TK, Saint R, Richards RI. Know thy fly. Trends Genet 2007; 23:238-42. [PMID: 17395332 DOI: 10.1016/j.tig.2007.03.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2006] [Revised: 01/29/2007] [Accepted: 03/12/2007] [Indexed: 11/23/2022]
Abstract
The generation and analysis of mutants is central to studies of gene function in model organisms. Methods for random mutagenesis in Drosophila melanogaster have been available for many years, but an alternative approach--targeted mutagenesis using homologous recombination--has only recently been developed. This approach has the advantage of specificity, because genes of interest can be altered. One might expect with a gene-targeting approach that the frequency of background mutations would be minimal. Unfortunately, we have found that this is not the case. Although the possibility of background mutations arising during homologous-recombination-based gene targeting has been raised in the literature, it is not routinely taken into account when using this technique. Our experience suggests that it can be a considerable problem but that it has a relatively simple solution.
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Affiliation(s)
- Louise V O'Keefe
- ARC Special Research Centre for the Molecular Genetics of Development, School of Molecular and Biomedical Sciences, The University of Adelaide, Adelaide, South Australia 5005, Australia
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Radford SJ, Goley E, Baxter K, McMahan S, Sekelsky J. Drosophila ERCC1 is required for a subset of MEI-9-dependent meiotic crossovers. Genetics 2005; 170:1737-45. [PMID: 15944364 PMCID: PMC1255914 DOI: 10.1534/genetics.104.036178] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2004] [Accepted: 04/29/2005] [Indexed: 01/28/2023] Open
Abstract
Drosophila MEI-9 is the catalytic subunit of a DNA structure-specific endonuclease required for nucleotide excision repair (NER). The enzymatic activity of this endonuclease during NER requires the presence of a second, noncatalytic subunit called ERCC1. In addition to its role in NER, MEI-9 is required for the generation of most meiotic crossovers. To better understand the role of MEI-9 in crossover formation, we report here the characterization of the Drosophila Ercc1 gene. We created an Ercc1 mutant through homologous gene targeting. We find that Ercc1 mutants are identical to mei-9 mutants in sensitivity to DNA-damaging agents, but have a less severe reduction in the number of meiotic crossovers. MEI-9 protein levels are reduced in Ercc1 mutants; however, overexpression of MEI-9 is not sufficient to restore meiotic crossing over in Ercc1 mutants. We conclude that MEI-9 can generate some meiotic crossovers in an ERCC1-independent manner.
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Affiliation(s)
- Sarah J Radford
- Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, North Carolina 27599, USA
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Kamura T, Maenaka K, Kotoshiba S, Matsumoto M, Kohda D, Conaway RC, Conaway JW, Nakayama KI. VHL-box and SOCS-box domains determine binding specificity for Cul2-Rbx1 and Cul5-Rbx2 modules of ubiquitin ligases. Genes Dev 2005; 18:3055-65. [PMID: 15601820 PMCID: PMC535916 DOI: 10.1101/gad.1252404] [Citation(s) in RCA: 389] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The ECS (Elongin B/C-Cul2/Cul5-SOCS-box protein) complex is a member of a family of ubiquitin ligases that share a Cullin-Rbx module. SOCS-box proteins recruit substrates to the ECS complex and are linked to Cullin-Rbx via Elongin B/C. VHL has been implicated as a SOCS-box protein, but lacks a C-terminal sequence (downstream of the BC box) of the SOCS box. We now show that VHL specifically interacts with endogenous Cul2-Rbx1 in mammalian cells, whereas SOCS-box proteins associate with Cul5-Rbx2. We also identify LRR-1 and FEM1B as proteins that share a region of homology with VHL (the VHL box, including the BC box and downstream residues) and associate with Cul2-Rbx1. ECS complexes can thus be classified into two distinct protein assemblies, that is, those that contain a subunit with a VHL box (composed of the BC box and a downstream Cul2 box) that interacts with Cul2-Rbx1, and those that contain a subunit with a SOCS box (BC box and downstream Cul5 box) that interacts with Cul5-Rbx2. Domain-swapping analyses showed that the specificity of interaction of VHL-box and SOCS-box proteins with Cullin-Rbx modules is determined by the Cul2 and Cul5 boxes, respectively. Finally, RNAi-mediated knockdown of the Cul2-Rbx1 inhibited the VHL-mediated degradation of HIF-2alpha, whereas knockdown of Cul5-Rbx2 did not affect it. These data suggest that the functions of the Cul2-Rbx1 and Cul5-Rbx2 modules are distinct.
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Affiliation(s)
- Takumi Kamura
- Department of Molecular and Cellular Biology, Medical Institute of Bioregulation, Kyushu University, Higashi-ku, Fukuoka, Fukuoka 812-8582, Japan
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