1
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Brockett JS, Manalo T, Zein-Sabatto H, Lee J, Fang J, Chu P, Feng H, Patil D, Davidson P, Ogan K, Master VA, Pattaras JG, Roberts DL, Bergquist SH, Reyna MA, Petros JA, Lerit DA, Arnold RS. A missense SNP in the tumor suppressor SETD2 reduces H3K36me3 and mitotic spindle integrity in Drosophila. Genetics 2024; 226:iyae015. [PMID: 38290049 PMCID: PMC10990431 DOI: 10.1093/genetics/iyae015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 01/11/2024] [Accepted: 01/11/2024] [Indexed: 02/01/2024] Open
Abstract
Mutations in SETD2 are among the most prevalent drivers of renal cell carcinoma (RCC). We identified a novel single nucleotide polymorphism (SNP) in SETD2, E902Q, within a subset of RCC patients, which manifests as both an inherited or tumor-associated somatic mutation. To determine if the SNP is biologically functional, we used CRISPR-based genome editing to generate the orthologous mutation within the Drosophila melanogaster Set2 gene. In Drosophila, the homologous amino acid substitution, E741Q, reduces H3K36me3 levels comparable to Set2 knockdown, and this loss is rescued by reintroduction of a wild-type Set2 transgene. We similarly uncovered significant defects in spindle morphogenesis, consistent with the established role of SETD2 in methylating α-Tubulin during mitosis to regulate microtubule dynamics and maintain genome stability. These data indicate the Set2 E741Q SNP affects both histone methylation and spindle integrity. Moreover, this work further suggests the SETD2 E902Q SNP may hold clinical relevance.
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Affiliation(s)
- Jovan S Brockett
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Tad Manalo
- Department of Urology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Hala Zein-Sabatto
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Jina Lee
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Junnan Fang
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Philip Chu
- Department of Urology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Harry Feng
- Department of Urology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Dattatraya Patil
- Department of Urology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Priscilla Davidson
- Department of Urology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Kenneth Ogan
- Department of Urology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Viraj A Master
- Department of Urology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - John G Pattaras
- Department of Urology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - David L Roberts
- Emory University Department of Medicine, Division of General Internal Medicine, Atlanta, GA 30322, USA
| | - Sharon H Bergquist
- Emory University Department of Medicine, Division of General Internal Medicine, Atlanta, GA 30322, USA
| | - Matthew A Reyna
- Department of Biomedical Informatics, Emory University School of Medicine, Atlanta, GA 30322, USA
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - John A Petros
- Department of Urology, Emory University School of Medicine, Atlanta, GA 30322, USA
- Winship Cancer Institute, Emory University, Atlanta, GA 30322, USA
| | - Dorothy A Lerit
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
- Winship Cancer Institute, Emory University, Atlanta, GA 30322, USA
| | - Rebecca S Arnold
- Department of Urology, Emory University School of Medicine, Atlanta, GA 30322, USA
- Winship Cancer Institute, Emory University, Atlanta, GA 30322, USA
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2
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Bakshi A, Iturra FE, Alamban A, Rosas-Salvans M, Dumont S, Aydogan MG. Cytoplasmic division cycles without the nucleus and mitotic CDK/cyclin complexes. Cell 2023; 186:4694-4709.e16. [PMID: 37832525 PMCID: PMC10659773 DOI: 10.1016/j.cell.2023.09.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Revised: 05/11/2023] [Accepted: 09/12/2023] [Indexed: 10/15/2023]
Abstract
Cytoplasmic divisions are thought to rely on nuclear divisions and mitotic signals. We demonstrate in Drosophila embryos that cytoplasm can divide repeatedly without nuclei and mitotic CDK/cyclin complexes. Cdk1 normally slows an otherwise faster cytoplasmic division cycle, coupling it with nuclear divisions, and when uncoupled, cytoplasm starts dividing before mitosis. In developing embryos where CDK/cyclin activity can license mitotic microtubule (MT) organizers like the spindle, cytoplasmic divisions can occur without the centrosome, a principal organizer of interphase MTs. However, centrosomes become essential in the absence of CDK/cyclin activity, implying that the cytoplasm can employ either the centrosome-based interphase or CDK/cyclin-dependent mitotic MTs to facilitate its divisions. Finally, we present evidence that autonomous cytoplasmic divisions occur during unperturbed fly embryogenesis and that they may help extrude mitotically stalled nuclei during blastoderm formation. We postulate that cytoplasmic divisions occur in cycles governed by a yet-to-be-uncovered clock mechanism autonomous from CDK/cyclin complexes.
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Affiliation(s)
- Anand Bakshi
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Fabio Echegaray Iturra
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Andrew Alamban
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA; Biophysics Graduate Program, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Miquel Rosas-Salvans
- Department of Bioengineering and Therapeutic Science, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Sophie Dumont
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA; Chan Zuckerberg Biohub, San Francisco, CA 94158, USA
| | - Mustafa G Aydogan
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA; Biophysics Graduate Program, University of California, San Francisco, San Francisco, CA 94158, USA.
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3
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Sokac AM, Biel N, De Renzis S. Membrane-actin interactions in morphogenesis: Lessons learned from Drosophila cellularization. Semin Cell Dev Biol 2023; 133:107-122. [PMID: 35396167 PMCID: PMC9532467 DOI: 10.1016/j.semcdb.2022.03.028] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 03/18/2022] [Accepted: 03/21/2022] [Indexed: 01/12/2023]
Abstract
During morphogenesis, changes in the shapes of individual cells are harnessed to mold an entire tissue. These changes in cell shapes require the coupled remodeling of the plasma membrane and underlying actin cytoskeleton. In this review, we highlight cellularization of the Drosophila embryo as a model system to uncover principles of how membrane and actin dynamics are co-regulated in space and time to drive morphogenesis.
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Affiliation(s)
- Anna Marie Sokac
- Department of Cell and Developmental Biology, University of Illinois at Urbana Champaign, Urbana, IL 61801, USA; Graduate Program in Integrative and Molecular Biomedical Sciences, Baylor College of Medicine, Houston, TX 77030, USA.
| | - Natalie Biel
- Department of Cell and Developmental Biology, University of Illinois at Urbana Champaign, Urbana, IL 61801, USA; Graduate Program in Integrative and Molecular Biomedical Sciences, Baylor College of Medicine, Houston, TX 77030, USA
| | - Stefano De Renzis
- European Molecular Biology Laboratory Heidelberg, 69117 Heidelberg, Germany
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4
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Xie B, Pu Y, Yang F, Chen W, Yue W, Ma J, Zhang N, Jiang Y, Wu J, Lin Y, Liang X, Wang C, Zou P, Li M. Proteomic Mapping and Targeting of Mitotic Pericentriolar Material in Tumors Bearing Centrosome Amplification. Cancer Res 2022; 82:2576-2592. [PMID: 35648393 DOI: 10.1158/0008-5472.can-22-0225] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 04/06/2022] [Accepted: 05/24/2022] [Indexed: 11/16/2022]
Abstract
Recent work has made it clear that pericentriolar material (PCM), the matrix of proteins surrounding centrioles, contributes to most functions of centrosomes. Given the occurrence of centrosome amplification in most solid tumors and the unconventional survival of these tumor cells, it is tempting to hypothesize that gel-like mitotic PCM would cluster extra centrosomes to defend against mitotic errors and increase tumor cell survival. However, because PCM lacks an encompassing membrane, is highly dynamic, and is physically connected to centrioles, few methods can decode the components of this microscale matrix. In this study, we took advantage of differential labeling between two sets of APEX2-centrosome reactions to design a strategy for acquiring the PCM proteome in living undisturbed cells without synchronization treatment, which identified 392 PCM proteins. Localization of ubiquitination promotion proteins away from PCM was a predominant mechanism to maintain the large size of PCM for centrosome clustering during mitosis in cancer cells. Depletion of PCM gene kinesin family member 20A (KIF20A) caused centrosome clustering failure and apoptosis in cancer cells in vitro and in vivo. Thus, our study suggests a strategy for targeting a wide range of tumors exhibiting centrosome amplification and provides a proteomic resource for future mining of PCM proteins. SIGNIFICANCE This study identifies the proteome of pericentriolar material and reveals therapeutic vulnerabilities in tumors bearing centrosome amplification.
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Affiliation(s)
- Bingteng Xie
- Center for Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing, P.R. China.,National Clinical Research Center for Obstetrics and Gynecology, Peking University Third Hospital, Beijing, P.R. China.,Key Laboratory of Assisted Reproduction, Ministry of Education, Peking University, Beijing, P.R. China.,Beijing Key Laboratory of Reproductive Endocrinology and Assisted Reproductive Technology, Peking University Third Hospital, Beijing, P.R. China
| | - Yang Pu
- State Key Laboratory of Medical Molecular Biology, Department of Physiology, Institute of Basic Medical Sciences and School of Basic Medicine, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, P.R. China
| | - Fan Yang
- College of Chemistry and Molecular Engineering, Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, P.R. China
| | - Wei Chen
- Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, P.R. China
| | - Wei Yue
- Center for Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing, P.R. China.,National Clinical Research Center for Obstetrics and Gynecology, Peking University Third Hospital, Beijing, P.R. China.,Key Laboratory of Assisted Reproduction, Ministry of Education, Peking University, Beijing, P.R. China.,Beijing Key Laboratory of Reproductive Endocrinology and Assisted Reproductive Technology, Peking University Third Hospital, Beijing, P.R. China
| | - Jihong Ma
- Center for Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing, P.R. China.,National Clinical Research Center for Obstetrics and Gynecology, Peking University Third Hospital, Beijing, P.R. China.,Key Laboratory of Assisted Reproduction, Ministry of Education, Peking University, Beijing, P.R. China.,Beijing Key Laboratory of Reproductive Endocrinology and Assisted Reproductive Technology, Peking University Third Hospital, Beijing, P.R. China
| | - Na Zhang
- Center for Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing, P.R. China.,National Clinical Research Center for Obstetrics and Gynecology, Peking University Third Hospital, Beijing, P.R. China.,Key Laboratory of Assisted Reproduction, Ministry of Education, Peking University, Beijing, P.R. China.,Beijing Key Laboratory of Reproductive Endocrinology and Assisted Reproductive Technology, Peking University Third Hospital, Beijing, P.R. China
| | - Yuening Jiang
- Center for Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing, P.R. China.,National Clinical Research Center for Obstetrics and Gynecology, Peking University Third Hospital, Beijing, P.R. China.,Key Laboratory of Assisted Reproduction, Ministry of Education, Peking University, Beijing, P.R. China.,Beijing Key Laboratory of Reproductive Endocrinology and Assisted Reproductive Technology, Peking University Third Hospital, Beijing, P.R. China
| | - Jiegen Wu
- Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, P.R. China
| | - Yihan Lin
- Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, P.R. China
| | - Xin Liang
- Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, P.R. China
| | - Chu Wang
- College of Chemistry and Molecular Engineering, Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, P.R. China
| | - Peng Zou
- College of Chemistry and Molecular Engineering, Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, P.R. China.,PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing, P.R. China.,Chinese Institute for Brain Research (CIBR), Beijing, P.R. China
| | - Mo Li
- Center for Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing, P.R. China.,National Clinical Research Center for Obstetrics and Gynecology, Peking University Third Hospital, Beijing, P.R. China.,Key Laboratory of Assisted Reproduction, Ministry of Education, Peking University, Beijing, P.R. China.,Beijing Key Laboratory of Reproductive Endocrinology and Assisted Reproductive Technology, Peking University Third Hospital, Beijing, P.R. China
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5
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Ghosh S, Lehner CF. Incorporation of CENP-A/CID into centromeres during early Drosophila embryogenesis does not require RNA polymerase II-mediated transcription. Chromosoma 2022; 131:1-17. [PMID: 35015118 PMCID: PMC9079035 DOI: 10.1007/s00412-022-00767-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 12/30/2021] [Accepted: 01/03/2022] [Indexed: 11/24/2022]
Abstract
In many species, centromere identity is specified epigenetically by special nucleosomes containing a centromere-specific histone H3 variant, designated as CENP-A in humans and CID in Drosophila melanogaster. After partitioning of centromere-specific nucleosomes onto newly replicated sister centromeres, loading of additional CENP-A/CID into centromeric chromatin is required for centromere maintenance in proliferating cells. Analyses with cultured cells have indicated that transcription of centromeric DNA by RNA polymerase II is required for deposition of new CID into centromere chromatin. However, a dependence of centromeric CID loading on transcription is difficult to reconcile with the notion that the initial embryonic stages appear to proceed in the absence of transcription in Drosophila, as also in many other animal species. To address the role of RNA polymerase II–mediated transcription for CID loading in early Drosophila embryos, we have quantified the effects of alpha-amanitin and triptolide on centromeric CID-EGFP levels. Our analyses demonstrate that microinjection of these two potent inhibitors of RNA polymerase II–mediated transcription has at most a marginal effect on centromeric CID deposition during progression through the early embryonic cleavage cycles. Thus, we conclude that at least during early Drosophila embryogenesis, incorporation of CID into centromeres does not depend on RNA polymerase II–mediated transcription.
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Affiliation(s)
- Samadri Ghosh
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
| | - Christian F Lehner
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland.
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6
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Cui M, Bai Y, Li K, Rong YS. Taming active transposons at Drosophila telomeres: The interconnection between HipHop's roles in capping and transcriptional silencing. PLoS Genet 2021; 17:e1009925. [PMID: 34813587 PMCID: PMC8651111 DOI: 10.1371/journal.pgen.1009925] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 12/07/2021] [Accepted: 11/03/2021] [Indexed: 11/19/2022] Open
Abstract
Drosophila chromosomes are elongated by retrotransposon attachment, a process poorly understood. Here we characterized a mutation affecting the HipHop telomere-capping protein. In mutant ovaries and the embryos that they produce, telomere retrotransposons are activated and transposon RNP accumulates. Genetic results are consistent with that this hiphop mutation weakens the efficacy of HP1-mediated silencing while leaving piRNA-based mechanisms largely intact. Remarkably, mutant females display normal fecundity suggesting that telomere de-silencing is compatible with germline development. Moreover, unlike prior mutants with overactive telomeres, the hiphop stock does not over-accumulate transposons for hundreds of generations. This is likely due to the loss of HipHop’s abilities both to silence transcription and to recruit transposons to telomeres in the mutant. Furthermore, embryos produced by mutant mothers experience a checkpoint activation, and a further loss of maternal HipHop leads to end-to-end fusion and embryonic arrest. Telomeric retroelements fulfill an essential function yet maintain a potentially conflicting relationship with their Drosophila host. Our study thus showcases a possible intermediate in this arm race in which the host is adapting to over-activated transposons while maintaining genome stability. Our results suggest that the collapse of such a relationship might only occur when the selfish element acquires the ability to target non-telomeric regions of the genome. HipHop is likely part of this machinery restricting the elements to the gene-poor region of telomeres. Lastly, our hiphop mutation behaves as a recessive suppressor of PEV that is mediated by centric heterochromatin, suggesting its broader effect on chromatin not limited to telomeres. Transposons are selfish elements that multiply by inserting extra copies of themselves into the host genome. Active transposons thus threaten the stability of the host genome, while the host responses by transcriptionally silencing the selfish elements or targeting their insertions towards gene-poor regions of the genome. Chromosome ends (telomeres) in the fruit fly Drosophila are elongated by active transposition of retrotransposons. Although much is known about how these elements are silenced, little is known about the remarkable accuracy by which they are targeted to telomeres. Prime candidates through which the host mounts such defenses are members of the protein complexes that protect telomeres. Here we characterized a hypomorphic mutation of the HipHop protein, and showed that active telomeric transcription in the mutant germline persists for generations without leading to runaway telomere elongation, that embryos laid by the mutant female suffer rampant end-to-end fusions, and that telomeric targeting of the transposon machinery is defective in the mutant soma. Collectively our data suggest that HipHop is essential for preventing telomere fusions, silencing telomeric transposons, and recruiting transposon machinery to telomeres. Our study thus identifies a factor essential for the host control over active transposons and a paradigm for studying such control mechanisms.
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Affiliation(s)
- Min Cui
- School of Life Sciences, Sun Yat-sen University, Guangzhou, China
- Hengyang College of Medicine, University of South China, Hengyang, China
| | - Yaofu Bai
- School of Life Sciences, Sun Yat-sen University, Guangzhou, China
- Hengyang College of Medicine, University of South China, Hengyang, China
| | - Kaili Li
- School of Life Sciences, Sun Yat-sen University, Guangzhou, China
- Hengyang College of Medicine, University of South China, Hengyang, China
| | - Yikang S. Rong
- Hengyang College of Medicine, University of South China, Hengyang, China
- * E-mail:
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7
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Lattao R, Rangone H, Llamazares S, Glover DM. Mauve/LYST limits fusion of lysosome-related organelles and promotes centrosomal recruitment of microtubule nucleating proteins. Dev Cell 2021; 56:1000-1013.e6. [PMID: 33725482 PMCID: PMC8024676 DOI: 10.1016/j.devcel.2021.02.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 11/17/2020] [Accepted: 02/17/2021] [Indexed: 11/28/2022]
Abstract
Lysosome-related organelles (LROs) are endosomal compartments carrying tissue-specific proteins, which become enlarged in Chediak-Higashi syndrome (CHS) due to mutations in LYST. Here, we show that Drosophila Mauve, a counterpart of LYST, suppresses vesicle fusion events with lipid droplets (LDs) during the formation of yolk granules (YGs), the LROs of the syncytial embryo, and opposes Rab5, which promotes fusion. Mauve localizes on YGs and at spindle poles, and it co-immunoprecipitates with the LDs' component and microtubule-associated protein Minispindles/Ch-TOG. Minispindles levels are increased at the enlarged YGs and diminished around centrosomes in mauve-derived mutant embryos. This leads to decreased microtubule nucleation from centrosomes, a defect that can be rescued by dominant-negative Rab5. Together, this reveals an unanticipated link between endosomal vesicles and centrosomes. These findings establish Mauve/LYST's role in regulating LRO formation and centrosome behavior, a role that could account for the enlarged LROs and centrosome positioning defects at the immune synapse of CHS patients.
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Affiliation(s)
- Ramona Lattao
- University of Cambridge, Department of Genetics, Downing Street, Cambridge CB23EH, UK.
| | - Hélène Rangone
- University of Cambridge, Department of Genetics, Downing Street, Cambridge CB23EH, UK
| | - Salud Llamazares
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Parc Cientific de Barcelona, C/ Baldiri Reixac 10, 08028 Barcelona, Spain
| | - David M Glover
- University of Cambridge, Department of Genetics, Downing Street, Cambridge CB23EH, UK; Division of Biology and Biological Engineering, California Institute of Technology, 1200 E, California Blvd, Pasadena, CA 91125, USA.
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8
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Gaskill MM, Gibson TJ, Larson ED, Harrison MM. GAF is essential for zygotic genome activation and chromatin accessibility in the early Drosophila embryo. eLife 2021; 10:e66668. [PMID: 33720012 PMCID: PMC8079149 DOI: 10.7554/elife.66668] [Citation(s) in RCA: 56] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 03/14/2021] [Indexed: 12/11/2022] Open
Abstract
Following fertilization, the genomes of the germ cells are reprogrammed to form the totipotent embryo. Pioneer transcription factors are essential for remodeling the chromatin and driving the initial wave of zygotic gene expression. In Drosophila melanogaster, the pioneer factor Zelda is essential for development through this dramatic period of reprogramming, known as the maternal-to-zygotic transition (MZT). However, it was unknown whether additional pioneer factors were required for this transition. We identified an additional maternally encoded factor required for development through the MZT, GAGA Factor (GAF). GAF is necessary to activate widespread zygotic transcription and to remodel the chromatin accessibility landscape. We demonstrated that Zelda preferentially controls expression of the earliest transcribed genes, while genes expressed during widespread activation are predominantly dependent on GAF. Thus, progression through the MZT requires coordination of multiple pioneer-like factors, and we propose that as development proceeds control is gradually transferred from Zelda to GAF.
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Affiliation(s)
- Marissa M Gaskill
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public HealthMadisonUnited States
| | - Tyler J Gibson
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public HealthMadisonUnited States
| | - Elizabeth D Larson
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public HealthMadisonUnited States
| | - Melissa M Harrison
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public HealthMadisonUnited States
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9
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Drosophila female germline stem cells undergo mitosis without nuclear breakdown. Curr Biol 2021; 31:1450-1462.e3. [PMID: 33548191 DOI: 10.1016/j.cub.2021.01.033] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 11/18/2020] [Accepted: 01/11/2021] [Indexed: 02/02/2023]
Abstract
Stem cell homeostasis requires nuclear lamina (NL) integrity. In Drosophila germ cells, compromised NL integrity activates the ataxia telangiectasia and Rad3-related (ATR) and checkpoint kinase 2 (Chk2) checkpoint kinases, blocking germ cell differentiation and causing germline stem cell (GSC) loss. Checkpoint activation occurs upon loss of either the NL protein emerin or its partner barrier-to-autointegration factor, two proteins required for nuclear reassembly at the end of mitosis. Here, we examined how mitosis contributes to NL structural defects linked to checkpoint activation. These analyses led to the unexpected discovery that wild-type female GSCs utilize a non-canonical mode of mitosis, one that retains a permeable but intact nuclear envelope and NL. We show that the interphase NL is remodeled during mitosis for insertion of centrosomes that nucleate the mitotic spindle within the confines of the nucleus. We show that depletion or loss of NL components causes mitotic defects, including compromised chromosome segregation associated with altered centrosome positioning and structure. Further, in emerin mutant GSCs, centrosomes remain embedded in the interphase NL. Notably, these embedded centrosomes carry large amounts of pericentriolar material and nucleate astral microtubules, revealing a role for emerin in the regulation of centrosome structure. Epistasis studies demonstrate that defects in centrosome structure are upstream of checkpoint activation, suggesting that these centrosome defects might trigger checkpoint activation and GSC loss. Connections between NL proteins and centrosome function have implications for mechanisms associated with NL dysfunction in other stem cell populations, including NL-associated diseases, such as laminopathies.
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10
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Wilhelm T, Said M, Naim V. DNA Replication Stress and Chromosomal Instability: Dangerous Liaisons. Genes (Basel) 2020; 11:E642. [PMID: 32532049 PMCID: PMC7348713 DOI: 10.3390/genes11060642] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 06/04/2020] [Accepted: 06/08/2020] [Indexed: 12/16/2022] Open
Abstract
Chromosomal instability (CIN) is associated with many human diseases, including neurodevelopmental or neurodegenerative conditions, age-related disorders and cancer, and is a key driver for disease initiation and progression. A major source of structural chromosome instability (s-CIN) leading to structural chromosome aberrations is "replication stress", a condition in which stalled or slowly progressing replication forks interfere with timely and error-free completion of the S phase. On the other hand, mitotic errors that result in chromosome mis-segregation are the cause of numerical chromosome instability (n-CIN) and aneuploidy. In this review, we will discuss recent evidence showing that these two forms of chromosomal instability can be mechanistically interlinked. We first summarize how replication stress causes structural and numerical CIN, focusing on mechanisms such as mitotic rescue of replication stress (MRRS) and centriole disengagement, which prevent or contribute to specific types of structural chromosome aberrations and segregation errors. We describe the main outcomes of segregation errors and how micronucleation and aneuploidy can be the key stimuli promoting inflammation, senescence, or chromothripsis. At the end, we discuss how CIN can reduce cellular fitness and may behave as an anticancer barrier in noncancerous cells or precancerous lesions, whereas it fuels genomic instability in the context of cancer, and how our current knowledge may be exploited for developing cancer therapies.
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Affiliation(s)
- Therese Wilhelm
- CNRS UMR9019 Genome Integrity and Cancers, Université Paris Saclay, Gustave Roussy, 94805 Villejuif, France; (T.W.); (M.S.)
- UMR144 Cell Biology and Cancer, Institut Curie, 75005 Paris, France
| | - Maha Said
- CNRS UMR9019 Genome Integrity and Cancers, Université Paris Saclay, Gustave Roussy, 94805 Villejuif, France; (T.W.); (M.S.)
| | - Valeria Naim
- CNRS UMR9019 Genome Integrity and Cancers, Université Paris Saclay, Gustave Roussy, 94805 Villejuif, France; (T.W.); (M.S.)
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11
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Debec A, Loppin B, Zheng C, Liu X, Megraw TL. The Enigma of Centriole Loss in the 1182-4 Cell Line. Cells 2020; 9:cells9051300. [PMID: 32456186 PMCID: PMC7290863 DOI: 10.3390/cells9051300] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Revised: 05/19/2020] [Accepted: 05/19/2020] [Indexed: 02/07/2023] Open
Abstract
The Drosophila melanogaster cell line 1182-4, which constitutively lacks centrioles, was established many years ago from haploid embryos laid by females homozygous for the maternal haploid (mh) mutation. This was the first clear example of animal cells regularly dividing in the absence of this organelle. However, the cause of the acentriolar nature of the 1182-4 cell line remained unclear and could not be clearly assigned to a particular genetic event. Here, we detail historically the longstanding mystery of the lack of centrioles in this Drosophila cell line. Recent advances, such as the characterization of the mh gene and the genomic analysis of 1182-4 cells, allow now a better understanding of the physiology of these cells. By combining these new data, we propose three reasonable hypotheses of the genesis of this remarkable phenotype.
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Affiliation(s)
- Alain Debec
- Institute of Ecology and Environmental Sciences, iEES, Sorbonne University, UPEC, CNRS, IRD, INRA, F-75005 Paris, France
- Correspondence: (A.D.); (B.L.); (T.L.M.)
| | - Benjamin Loppin
- Laboratoire de Biologie et de Modélisation de la Cellule—CNRS UMR 5239, École Normale Supérieure de Lyon, University of Lyon, F-69007 Lyon, France
- Correspondence: (A.D.); (B.L.); (T.L.M.)
| | - Chunfeng Zheng
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL 32306-4300, USA;
| | - Xiuwen Liu
- Department of Computer Science, Florida State University, Tallahassee, FL 32306-4530, USA;
| | - Timothy L. Megraw
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL 32306-4300, USA;
- Correspondence: (A.D.); (B.L.); (T.L.M.)
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12
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Rincón AM, Monje-Casas F. A guiding torch at the poles: the multiple roles of spindle microtubule-organizing centers during cell division. Cell Cycle 2020; 19:1405-1421. [PMID: 32401610 DOI: 10.1080/15384101.2020.1754586] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Abstract
The spindle constitutes the cellular machinery that enables the segregation of the chromosomes during eukaryotic cell division. The microtubules that form this fascinating and complex genome distribution system emanate from specialized structures located at both its poles and known as microtubule-organizing centers (MTOCs). Beyond their structural function, the spindle MTOCs play fundamental roles in cell cycle control, the activation and functionality of the mitotic checkpoints and during cellular aging. This review highlights the pivotal importance of spindle-associated MTOCs in multiple cellular processes and their central role as key regulatory hubs where diverse intracellular signals are integrated and coordinated to ensure the successful completion of cell division and the maintenance of the replicative lifespan.
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Affiliation(s)
- Ana M Rincón
- Centro Andaluz de Biología Molecular Y Medicina Regenerativa (CABIMER) / CSIC - Universidad de Sevilla - Universidad Pablo de Olavide , Sevilla, Spain.,Dpto. de Genética / Universidad de Sevilla , Sevilla, Spain
| | - Fernando Monje-Casas
- Centro Andaluz de Biología Molecular Y Medicina Regenerativa (CABIMER) / CSIC - Universidad de Sevilla - Universidad Pablo de Olavide , Sevilla, Spain.,Consejo Superior de Investigaciones Científicas (CSIC) , Sevilla, Spain
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13
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Harpprecht L, Baldi S, Schauer T, Schmidt A, Bange T, Robles MS, Kremmer E, Imhof A, Becker PB. A Drosophila cell-free system that senses DNA breaks and triggers phosphorylation signalling. Nucleic Acids Res 2019; 47:7444-7459. [PMID: 31147711 PMCID: PMC6698661 DOI: 10.1093/nar/gkz473] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 05/13/2019] [Accepted: 05/16/2019] [Indexed: 11/23/2022] Open
Abstract
Preblastoderm Drosophila embryo development is characterized by fast cycles of nuclear divisions. Extracts from these embryos can be used to reconstitute complex chromatin with high efficiency. We now discovered that this chromatin assembly system contains activities that recognize unprotected DNA ends and signal DNA damage through phosphorylation. DNA ends are initially bound by Ku and MRN complexes. Within minutes, the phosphorylation of H2A.V (homologous to γH2A.X) initiates from DNA breaks and spreads over tens of thousands DNA base pairs. The γH2A.V phosphorylation remains tightly associated with the damaged DNA and does not spread to undamaged DNA in the same reaction. This first observation of long-range γH2A.X spreading along damaged chromatin in an in vitro system provides a unique opportunity for mechanistic dissection. Upon further incubation, DNA ends are rendered single-stranded and bound by the RPA complex. Phosphoproteome analyses reveal damage-dependent phosphorylation of numerous DNA-end-associated proteins including Ku70, RPA2, CHRAC16, the exonuclease Rrp1 and the telomer capping complex. Phosphorylation of spindle assembly checkpoint components and of microtubule-associated proteins required for centrosome integrity suggests this cell-free system recapitulates processes involved in the regulated elimination of fatally damaged syncytial nuclei.
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Affiliation(s)
- Lisa Harpprecht
- Molecular Biology Division, Biomedical Center, LMU Munich, 82152 Planegg-Martinsried, Germany
| | - Sandro Baldi
- Molecular Biology Division, Biomedical Center, LMU Munich, 82152 Planegg-Martinsried, Germany
- Center for Integrated Protein Science Munich, LMU Munich, 81377 Munich, Germany
| | - Tamas Schauer
- Molecular Biology Division, Biomedical Center, LMU Munich, 82152 Planegg-Martinsried, Germany
- Bioinformatics Unit, Biomedical Center, LMU Munich, 82152 Planegg-Martinsried, Germany
| | - Andreas Schmidt
- Molecular Biology Division, Biomedical Center, LMU Munich, 82152 Planegg-Martinsried, Germany
- Protein Analysis Unit, Biomedical Center, LMU Munich, 82152 Planegg-Martinsried, Germany
| | - Tanja Bange
- Institute of Medical Psychology, LMU Munich, 80336 Munich, Germany
| | - Maria S Robles
- Institute of Medical Psychology, LMU Munich, 80336 Munich, Germany
| | - Elisabeth Kremmer
- Institute of Molecular Immunology, German Research Center for Environmental Health, 81377 Munich, Germany
| | - Axel Imhof
- Molecular Biology Division, Biomedical Center, LMU Munich, 82152 Planegg-Martinsried, Germany
- Center for Integrated Protein Science Munich, LMU Munich, 81377 Munich, Germany
- Protein Analysis Unit, Biomedical Center, LMU Munich, 82152 Planegg-Martinsried, Germany
| | - Peter B Becker
- Molecular Biology Division, Biomedical Center, LMU Munich, 82152 Planegg-Martinsried, Germany
- Center for Integrated Protein Science Munich, LMU Munich, 81377 Munich, Germany
- To whom correspondence should be addressed. Tel: +49 89 2180 75427; Fax: +49 89 2180 75425;
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14
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Yu L, Li G, Deng J, Jiang X, Xue J, Zhu Y, Huang W, Tang B, Duan R. The UFM1 cascade times mitosis entry associated with microcephaly. FASEB J 2019; 34:1319-1330. [PMID: 31914610 DOI: 10.1096/fj.201901751r] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 10/15/2019] [Accepted: 11/14/2019] [Indexed: 02/02/2023]
Abstract
Posttranslational modifications enhance the functional diversity of the proteome by modifying the substrates. The UFM1 cascade is a novel ubiquitin-like modification system. The mutations in UFM1, its E1 (UBA5) and E2 (UFC1), have been identified in patients with microcephaly. However, its pathological mechanisms remain unclear. Herein, we observed the disruption of the UFM1 cascade in Drosophila neuroblasts (NBs) decreased the number of NBs, leading to a smaller brain size. The lack of ufmylation in NBs resulted in an increased mitotic index and an extended G2/M phase, indicating a defect in mitotic progression. In addition, live imaging of the embryos revealed an impaired E3 ligase (Ufl1) function resulted in premature entry into mitosis and failed cellularization. Even worse, the embryonic lethality occurred as early as within the first few mitotic cycles following the depletion of Ufm1. Knockdown of ufmylation in the fixed embryos exhibited severe phenotypes, including detached centrosomes, defective microtubules, and DNA bridge. Furthermore, we observed that the UFM1 cascade could alter the level of phosphorylation on tyrosine-15 of CDK1 (pY15-CDK1), which is a negative regulator of the G2 to M transition. These findings yield unambiguous evidence suggesting that the UFM1 cascade is a microcephaly-causing factor that regulates the progression of the cell cycle at mitosis phase entry.
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Affiliation(s)
- Li Yu
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, China.,Hunan Key Laboratory of Medical Genetics, Central South University, Changsha, China
| | - Guangxu Li
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, China.,Hunan Key Laboratory of Medical Genetics, Central South University, Changsha, China
| | - Jing Deng
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, China.,Hunan Key Laboratory of Medical Genetics, Central South University, Changsha, China
| | - Xuan Jiang
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, China.,Hunan Key Laboratory of Medical Genetics, Central South University, Changsha, China
| | - Jin Xue
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, China.,Hunan Key Laboratory of Medical Genetics, Central South University, Changsha, China
| | - Yingbao Zhu
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, China.,Hunan Key Laboratory of Medical Genetics, Central South University, Changsha, China
| | - Wen Huang
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, China.,Hunan Key Laboratory of Medical Genetics, Central South University, Changsha, China
| | - Beisha Tang
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, China.,Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Ranhui Duan
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, China.,Hunan Key Laboratory of Medical Genetics, Central South University, Changsha, China.,Hunan Key Laboratory of Animal Models for Human Diseases, Central South University, Changsha, China
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15
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Spracklen AJ, Thornton-Kolbe EM, Bonner AN, Florea A, Compton PJ, Fernandez-Gonzalez R, Peifer M. The Crk adapter protein is essential for Drosophila embryogenesis, where it regulates multiple actin-dependent morphogenic events. Mol Biol Cell 2019; 30:2399-2421. [PMID: 31318326 PMCID: PMC6741062 DOI: 10.1091/mbc.e19-05-0302] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Small Src homology domain 2 (SH2) and 3 (SH3) adapter proteins regulate cell fate and behavior by mediating interactions between cell surface receptors and downstream signaling effectors in many signal transduction pathways. The CT10 regulator of kinase (Crk) family has tissue-specific roles in phagocytosis, cell migration, and neuronal development and mediates oncogenic signaling in pathways like that of Abelson kinase. However, redundancy among the two mammalian family members and the position of the Drosophila gene on the fourth chromosome precluded assessment of Crk's full role in embryogenesis. We circumvented these limitations with short hairpin RNA and CRISPR technology to assess Crk's function in Drosophila morphogenesis. We found that Crk is essential beginning in the first few hours of development, where it ensures accurate mitosis by regulating orchestrated dynamics of the actin cytoskeleton to keep mitotic spindles in syncytial embryos from colliding. In this role, it positively regulates cortical localization of the actin-related protein 2/3 complex (Arp2/3), its regulator suppressor of cAMP receptor (SCAR), and filamentous actin to actin caps and pseudocleavage furrows. Crk loss leads to the loss of nuclei and formation of multinucleate cells. We also found roles for Crk in embryonic wound healing and in axon patterning in the nervous system, where it localizes to the axons and midline glia. Thus, Crk regulates diverse events in embryogenesis that require orchestrated cytoskeletal dynamics.
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Affiliation(s)
- Andrew J Spracklen
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Emma M Thornton-Kolbe
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Alison N Bonner
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Alexandru Florea
- Institute of Biomaterials and Biomedical Engineering, Ted Rogers Centre for Heart Research, and Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Peter J Compton
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Rodrigo Fernandez-Gonzalez
- Institute of Biomaterials and Biomedical Engineering, Ted Rogers Centre for Heart Research, and Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Mark Peifer
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599.,Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599.,Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
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16
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Blake-Hedges C, Megraw TL. Coordination of Embryogenesis by the Centrosome in Drosophila melanogaster. Results Probl Cell Differ 2019; 67:277-321. [PMID: 31435800 DOI: 10.1007/978-3-030-23173-6_12] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The first 3 h of Drosophila melanogaster embryo development are exemplified by rapid nuclear divisions within a large syncytium, transforming the zygote to the cellular blastoderm after 13 successive cleavage divisions. As the syncytial embryo develops, it relies on centrosomes and cytoskeletal dynamics to transport nuclei, maintain uniform nuclear distribution throughout cleavage cycles, ensure generation of germ cells, and coordinate cellularization. For the sake of this review, we classify six early embryo stages that rely on processes coordinated by the centrosome and its regulation of the cytoskeleton. The first stage features migration of one of the female pronuclei toward the male pronucleus following maturation of the first embryonic centrosomes. Two subsequent stages distribute the nuclei first axially and then radially in the embryo. The remaining three stages involve centrosome-actin dynamics that control cortical plasma membrane morphogenesis. In this review, we highlight the dynamics of the centrosome and its role in controlling the six stages that culminate in the cellularization of the blastoderm embryo.
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Affiliation(s)
- Caitlyn Blake-Hedges
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL, USA.
| | - Timothy L Megraw
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL, USA
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17
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Graziadio L, Palumbo V, Cipressa F, Williams BC, Cenci G, Gatti M, Goldberg ML, Bonaccorsi S. Phenotypic characterization of diamond (dind), a Drosophila gene required for multiple aspects of cell division. Chromosoma 2018; 127:489-504. [PMID: 30120539 DOI: 10.1007/s00412-018-0680-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 08/01/2018] [Accepted: 08/03/2018] [Indexed: 01/04/2023]
Abstract
Many genes are required for the assembly of the mitotic apparatus and for proper chromosome behavior during mitosis and meiosis. A fruitful approach to elucidate the mechanisms underlying cell division is the accurate phenotypic characterization of mutations in these genes. Here, we report the identification and characterization of diamond (dind), an essential Drosophila gene required both for mitosis of larval brain cells and for male meiosis. Larvae homozygous for any of the five EMS-induced mutations die in the third-instar stage and exhibit multiple mitotic defects. Mutant brain cells exhibit poorly condensed chromosomes and frequent chromosome breaks and rearrangements; they also show centriole fragmentation, disorganized mitotic spindles, defective chromosome segregation, endoreduplicated metaphases, and hyperploid and polyploid cells. Comparable phenotypes occur in mutant spermatogonia and spermatocytes. The dind gene encodes a non-conserved protein with no known functional motifs. Although the Dind protein exhibits a rather diffuse localization in both interphase and mitotic cells, fractionation experiments indicate that some Dind is tightly associated with the chromatin. Collectively, these results suggest that loss of Dind affects chromatin organization leading to defects in chromosome condensation and integrity, which in turn affect centriole stability and spindle assembly. However, our results do not exclude the possibility that Dind directly affects some behaviors of the spindle and centrosomes.
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Affiliation(s)
- Lucia Graziadio
- Dipartimento di Biologia e Biotecnologie "C. Darwin", Sapienza, Università di Roma, Rome, Italy
| | - Valeria Palumbo
- Dipartimento di Biologia e Biotecnologie "C. Darwin", Sapienza, Università di Roma, Rome, Italy
| | - Francesca Cipressa
- Dipartimento di Biologia e Biotecnologie "C. Darwin", Sapienza, Università di Roma, Rome, Italy.,Museo storico della fisica e centro di studi e ricerche Enrico Fermi, Rome, Italy
| | - Byron C Williams
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, 14853, USA
| | - Giovanni Cenci
- Dipartimento di Biologia e Biotecnologie "C. Darwin", Sapienza, Università di Roma, Rome, Italy.,Istituto Pasteur Fondazione Cenci Bolognetti, Rome, Italy
| | - Maurizio Gatti
- Dipartimento di Biologia e Biotecnologie "C. Darwin", Sapienza, Università di Roma, Rome, Italy.,Istituto di Biologia e Patologia Molecolari (IBPM) del CNR, Rome, Italy
| | - Michael L Goldberg
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, 14853, USA.
| | - Silvia Bonaccorsi
- Dipartimento di Biologia e Biotecnologie "C. Darwin", Sapienza, Università di Roma, Rome, Italy.
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18
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Rogne M, Svaerd O, Madsen-Østerbye J, Hashim A, Tjønnfjord GE, Staerk J. Cytokinesis arrest and multiple centrosomes in B cell chronic lymphocytic leukaemia. J Cell Mol Med 2018. [PMID: 29516674 PMCID: PMC5908127 DOI: 10.1111/jcmm.13579] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Cytokinesis failure leads to the emergence of tetraploid cells and multiple centrosomes. Chronic lymphocytic leukaemia (CLL) is the most common haematological malignancy in adults and is characterized by clonal B cell expansion. Here, we show that a significant number of peripheral blood CLL cells are arrested in cytokinesis and that this event occurred after nuclear envelope reformation and before cytoplasmic abscission. mRNA expression data showed that several genes known to be crucial for cell cycle regulation, checkpoint and centromere function, such as ING4, ING5, CDKN1A and CDK4, were significantly dysregulated in CLL samples. Our results demonstrate that CLL cells exhibit difficulties in completing mitosis, which is different from but may, at least in part, explain the previously reported accumulation of CLL cells in G0/1.
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Affiliation(s)
- Marie Rogne
- Centre for Molecular Medicine Norway, Nordic European Molecular Laboratory Partnership, University of Oslo, Oslo, Norway
| | - Oksana Svaerd
- Centre for Molecular Medicine Norway, Nordic European Molecular Laboratory Partnership, University of Oslo, Oslo, Norway
| | - Julia Madsen-Østerbye
- Centre for Molecular Medicine Norway, Nordic European Molecular Laboratory Partnership, University of Oslo, Oslo, Norway
| | - Adnan Hashim
- Centre for Molecular Medicine Norway, Nordic European Molecular Laboratory Partnership, University of Oslo, Oslo, Norway
| | - Geir E Tjønnfjord
- Department of Haematology, Oslo University Hospital, Oslo, Norway.,Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Judith Staerk
- Centre for Molecular Medicine Norway, Nordic European Molecular Laboratory Partnership, University of Oslo, Oslo, Norway.,Department of Haematology, Oslo University Hospital, Oslo, Norway.,Norwegian Center for Stem Cell Research, Department of Immunology, Oslo University Hospital, Oslo, Norway
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19
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Biochemical Fractionation of Time-Resolved Drosophila Embryos Reveals Similar Transcriptomic Alterations in Replication Checkpoint and Histone mRNA Processing Mutants. J Mol Biol 2017; 429:3264-3279. [DOI: 10.1016/j.jmb.2017.01.022] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 01/28/2017] [Accepted: 01/30/2017] [Indexed: 11/22/2022]
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20
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Rapid DNA Synthesis During Early Drosophila Embryogenesis Is Sensitive to Maternal Humpty Dumpty Protein Function. Genetics 2017; 207:935-947. [PMID: 28942426 DOI: 10.1534/genetics.117.300318] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 09/20/2017] [Indexed: 12/29/2022] Open
Abstract
Problems with DNA replication cause cancer and developmental malformations. It is not fully understood how DNA replication is coordinated with development and perturbed in disease. We had previously identified the Drosophila gene humpty dumpty (hd), and showed that null alleles cause incomplete DNA replication, tissue undergrowth, and lethality. Animals homozygous for the missense allele, hd272-9 , were viable, but adult females had impaired amplification of eggshell protein genes in the ovary, resulting in the maternal effects of thin eggshells and embryonic lethality. Here, we show that expression of an hd transgene in somatic cells of the ovary rescues amplification and eggshell synthesis but not embryo viability. The germline of these mothers remain mutant for the hd272-9 allele, resulting in reduced maternal Hd protein and embryonic arrest during mitosis of the first few S/M nuclear cleavage cycles with chromosome instability and chromosome bridges. Epistasis analysis of hd with the rereplication mutation plutonium indicates that the chromosome bridges of hd embryos are the result of a failed attempt to segregate incompletely replicated sister chromatids. This study reveals that maternally encoded Humpty dumpty protein is essential for DNA replication and genome integrity during the little-understood embryonic S/M cycles. Moreover, the two hd272-9 maternal-effect phenotypes suggest that ovarian gene amplification and embryonic cleavage are two time periods in development that are particularly sensitive to mild deficits in DNA replication function. This last observation has broader relevance for interpreting why mild mutations in the human ortholog of humpty dumpty and other DNA replication genes cause tissue-specific malformations of microcephalic dwarfisms.
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21
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Lu KL, Yamashita YM. Germ cell connectivity enhances cell death in response to DNA damage in the Drosophila testis. eLife 2017; 6:27960. [PMID: 28809158 PMCID: PMC5577909 DOI: 10.7554/elife.27960] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 07/21/2017] [Indexed: 12/25/2022] Open
Abstract
Two broadly known characteristics of germ cells in many organisms are their development as a ‘cyst’ of interconnected cells and their high sensitivity to DNA damage. Here we provide evidence that in the Drosophila testis, connectivity serves as a mechanism that confers to spermatogonia a high sensitivity to DNA damage. We show that all spermatogonia within a cyst die synchronously even when only a subset of them exhibit detectable DNA damage. Mutants of the fusome, an organelle that is known to facilitate intracyst communication, compromise synchronous spermatogonial death and reduces overall germ cell death. Our data indicate that a death-promoting signal is shared within the cyst, leading to death of the entire cyst. Taken together, we propose that intercellular connectivity supported by the fusome uniquely increases the sensitivity of the germline to DNA damage, thereby protecting the integrity of gamete genomes that are passed on to the next generation.
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Affiliation(s)
- Kevin L Lu
- Life Sciences Institute, University of Michigan, Ann Arbor, United States.,Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, United States.,Medical Scientist Training Program, University of Michigan, Ann Arbor, United States
| | - Yukiko M Yamashita
- Life Sciences Institute, University of Michigan, Ann Arbor, United States.,Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, United States.,Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, United States.,Howard Hughes Medical Institute, University of Michigan, Ann Arbor, United States
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22
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Calpain A controls mitotic synchrony in the Drosophila blastoderm embryo. Mech Dev 2017; 144:141-149. [DOI: 10.1016/j.mod.2016.05.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Revised: 05/27/2016] [Accepted: 05/31/2016] [Indexed: 01/10/2023]
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23
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Abstract
The maintenance of genome stability is critical for proper cell function, and loss of this stability contributes to many human diseases and developmental disorders. Therefore, cells have evolved partially redundant mechanisms to monitor and protect the genome. One subcellular organelle implicated in the maintenance of genome stability is the centrosome, best known as the primary microtubule organizing center of most animal cells. Centrosomes serve many different roles throughout the cell cycle, and many of those roles, including mitotic spindle assembly, nucleation of the interphase microtubule array, DNA damage response, and efficient cell cycle progression, have been proposed to help maintain genome stability. As a result, the centrosome is itself a highly regulated entity. Here, we review evidence concerning the significance of the centrosome in promoting genome integrity. Recent advances permitting acute and persistent centrosome removal suggest we still have much to learn regarding the specific function and actual importance of centrosomes in different contexts, as well as how cells may compensate for centrosome dysfunction to maintain the integrity of the genome. Although many animal cells survive and proliferate in the absence of centrosomes, they do so aberrantly. Based on these and other studies, we conclude that centrosomes serve as critical, multifunctional organelles that promote genome stability.
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Affiliation(s)
- Dorothy A Lerit
- Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute; National Institutes of Health, Bethesda, MD, 20892, USA.
- National Institutes of Health, 50 South Drive, Building 50, Room 2122, Bethesda, MD, 20892, USA.
| | - John S Poulton
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC, 27599, USA.
- University of North Carolina, Fordham 519, CB#3280, Chapel Hill, NC, 27599, USA.
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24
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Abstract
Here, we review how DNA damage affects the centrosome and how centrosomes communicate with the DNA damage response (DDR) apparatus. We discuss how several proteins of the DDR are found at centrosomes, including the ATM, ATR, CHK1 and CHK2 kinases, the BRCA1 ubiquitin ligase complex and several members of the poly(ADP-ribose) polymerase family. Stereotypical centrosome organisation, in which two centriole barrels are orthogonally arranged in a roughly toroidal pericentriolar material (PCM), is strongly affected by exposure to DNA-damaging agents. We describe the genetic dependencies and mechanisms for how the centrioles lose their close association, and the PCM both expands and distorts after DNA damage. Another consequence of genotoxic stress is that centrosomes undergo duplication outside the normal cell cycle stage, meaning that centrosome amplification is commonly seen after DNA damage. We discuss several potential mechanisms for how centrosome numbers become dysregulated after DNA damage and explore the links between the DDR and the PLK1- and separase-dependent mechanisms that drive centriole separation and reduplication. We also describe how centrosome components, such as centrin2, are directly involved in responding to DNA damage. This review outlines current questions on the involvement of centrosomes in the DDR.
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Affiliation(s)
- Lisa I Mullee
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Biosciences Building, Dangan, Galway, Ireland
| | - Ciaran G Morrison
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Biosciences Building, Dangan, Galway, Ireland.
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25
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Ma X, Han Y, Song X, Do T, Yang Z, Ni J, Xie T. DNA damage-induced Lok/CHK2 activation compromises germline stem cell self-renewal and lineage differentiation. Development 2016; 143:4312-4323. [PMID: 27729408 DOI: 10.1242/dev.141069] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 09/20/2016] [Indexed: 12/21/2022]
Abstract
Stem cells in adult tissues are constantly exposed to genotoxic stress and also accumulate DNA damage with age. However, it remains largely unknown how DNA damage affects both stem cell self-renewal and differentiation. In this study, we show that DNA damage retards germline stem cell (GSC) self-renewal and progeny differentiation in a Lok kinase-dependent manner in the Drosophila ovary. Both heatshock-inducible endonuclease I-CreI expression and X-ray irradiation can efficiently introduce double-strand breaks in GSCs and their progeny, resulting in a rapid GSC loss and a GSC progeny differentiation defect. Surprisingly, the elimination of Lok or its kinase activity can almost fully rescue the GSC loss and the progeny differentiation defect caused by DNA damage induced by I-CreI or X-ray. In addition, the reduction in bone morphogenetic protein signaling and Shotgun expression only makes a limited contribution to DNA damage-induced GSC loss. Finally, DNA damage also decreases the expression of the master differentiation factor Bam in a Lok-dependent manner, which helps explain the GSC progeny differentiation defect. Therefore, this study demonstrates, for the first time in vivo, that Lok kinase activation is required for the DNA damage-mediated disruption of adult stem cell self-renewal and lineage differentiation, and might also offer novel insight into how DNA damage causes tissue aging and cancer formation.
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Affiliation(s)
- Xing Ma
- Stowers Institute for Medical Research, 1000 East 50th Street, Kansas City, MO 64110, USA.,Department of Cell Biology and Anatomy, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Yingying Han
- Stowers Institute for Medical Research, 1000 East 50th Street, Kansas City, MO 64110, USA
| | - Xiaoqing Song
- Stowers Institute for Medical Research, 1000 East 50th Street, Kansas City, MO 64110, USA
| | - Trieu Do
- Stowers Institute for Medical Research, 1000 East 50th Street, Kansas City, MO 64110, USA
| | - Zhihao Yang
- Tsinghua University School of Medicine, Beijing 100084, China
| | - Jianquan Ni
- Tsinghua University School of Medicine, Beijing 100084, China
| | - Ting Xie
- Stowers Institute for Medical Research, 1000 East 50th Street, Kansas City, MO 64110, USA .,Department of Cell Biology and Anatomy, University of Kansas Medical Center, Kansas City, KS 66160, USA
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Tran M, Tsarouhas V, Kegel A. Early development of Drosophila embryos requires Smc5/6 function during oogenesis. Biol Open 2016; 5:928-41. [PMID: 27288507 PMCID: PMC4958276 DOI: 10.1242/bio.019000] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Mutations in structural maintenance of chromosomes (Smc) proteins are frequently associated with chromosomal abnormalities commonly observed in developmental disorders. However, the role of Smc proteins in development still remains elusive. To investigate Smc5/6 function during early embryogenesis we examined smc5 and smc6 mutants of the fruit fly Drosophila melanogaster using a combination of reverse genetics and microscopy approaches. Smc5/6 exhibited a maternally contributed function in maintaining chromosome stability during early embryo development, which manifested as female subfertility in its absence. Loss of Smc5/6 caused an arrest and a considerable delay in embryo development accompanied by fragmented nuclei and increased anaphase-bridge formation, respectively. Surprisingly, early embryonic arrest was attributable to the absence of Smc5/6 during oogenesis, which resulted in insufficient repair of pre-meiotic and meiotic DNA double-strand breaks. Thus, our findings contribute to the understanding of Smc proteins in higher eukaryotic development by highlighting a maternal function in chromosome maintenance and a link between oogenesis and early embryogenesis. Summary: Early emerging problems during oogenesis, such as DNA double-strand breaks, can affect chromosome duplication and segregation in embryogenesis in Drosophila. Moreover, environmental cues including temperature are important for proper oogenesis.
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Affiliation(s)
- Martin Tran
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm S-17177, Sweden
| | - Vasilios Tsarouhas
- Department of Molecular Bioscience, The Wenner-Gren Institute, Stockholm University, Stockholm S-10691, Sweden
| | - Andreas Kegel
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm S-17177, Sweden
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The Deadbeat Paternal Effect of Uncapped Sperm Telomeres on Cell Cycle Progression and Chromosome Behavior in Drosophila melanogaster. Genetics 2016; 203:799-816. [PMID: 27029731 DOI: 10.1534/genetics.115.182436] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Accepted: 03/27/2016] [Indexed: 12/24/2022] Open
Abstract
Telomere-capping complexes (TCCs) protect the ends of linear chromosomes from illegitimate repair and end-to-end fusions and are required for genome stability. The identity and assembly of TCC components have been extensively studied, but whether TCCs require active maintenance in nondividing cells remains an open question. Here we show that Drosophila melanogaster requires Deadbeat (Ddbt), a sperm nuclear basic protein (SNBP) that is recruited to the telomere by the TCC and is required for TCC maintenance during genome-wide chromatin remodeling, which transforms spermatids to mature sperm. Ddbt-deficient males produce sperm lacking TCCs. Their offspring delay the initiation of anaphase as early as cycle 1 but progress through the first two cycles. Persistence of uncapped paternal chromosomes induces arrest at or around cycle 3. This early arrest can be rescued by selective elimination of paternal chromosomes and production of gynogenetic haploid or haploid mosaics. Progression past cycle 3 can also occur if embryos have reduced levels of the maternally provided checkpoint kinase Chk2. The findings provide insights into how telomere integrity affects the regulation of the earliest embryonic cell cycles. They also suggest that other SNBPs, including those in humans, may have analogous roles and manifest as paternal effects on embryo quality.
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Abstract
Over a century ago, centrosome aberrations were postulated to cause cancer by promoting genome instability. The mechanisms governing centrosome assembly and function are increasingly well understood, allowing for a timely reappraisal of this postulate. This Review discusses recent advances that shed new light on the relationship between centrosomes and cancer, and raise the possibility that centrosome aberrations contribute to this disease in different ways than initially envisaged.
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Affiliation(s)
- Pierre Gönczy
- Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, Swiss Federal Institute of Technology (EPFL), CH-1015 Lausanne, Switzerland
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29
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Lerit DA, Jordan HA, Poulton JS, Fagerstrom CJ, Galletta BJ, Peifer M, Rusan NM. Interphase centrosome organization by the PLP-Cnn scaffold is required for centrosome function. J Cell Biol 2015; 210:79-97. [PMID: 26150390 PMCID: PMC4494003 DOI: 10.1083/jcb.201503117] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Cnn and PLP directly interact at two defined sites to coordinate the cell cycle–dependent rearrangement and scaffolding activity of the centrosome to permit normal centrosome organization, cell division, and embryonic viability. Pericentriolar material (PCM) mediates the microtubule (MT) nucleation and anchoring activity of centrosomes. A scaffold organized by Centrosomin (Cnn) serves to ensure proper PCM architecture and functional changes in centrosome activity with each cell cycle. Here, we investigate the mechanisms that spatially restrict and temporally coordinate centrosome scaffold formation. Focusing on the mitotic-to-interphase transition in Drosophila melanogaster embryos, we show that the elaboration of the interphase Cnn scaffold defines a major structural rearrangement of the centrosome. We identify an unprecedented role for Pericentrin-like protein (PLP), which localizes to the tips of extended Cnn flares, to maintain robust interphase centrosome activity and promote the formation of interphase MT asters required for normal nuclear spacing, centrosome segregation, and compartmentalization of the syncytial embryo. Our data reveal that Cnn and PLP directly interact at two defined sites to coordinate the cell cycle–dependent rearrangement and scaffolding activity of the centrosome to permit normal centrosome organization, cell division, and embryonic viability.
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Affiliation(s)
- Dorothy A Lerit
- Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892
| | - Holly A Jordan
- Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892
| | - John S Poulton
- Biology Department, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Carey J Fagerstrom
- Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892
| | - Brian J Galletta
- Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892
| | - Mark Peifer
- Biology Department, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Nasser M Rusan
- Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892
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30
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Abstract
A veritable explosion of primary research papers within the past 10 years focuses on nucleolar and ribosomal stress, and for good reason: with ribosome biosynthesis consuming ~80% of a cell’s energy, nearly all metabolic and signaling pathways lead ultimately to or from the nucleolus. We begin by describing p53 activation upon nucleolar stress resulting in cell cycle arrest or apoptosis. The significance of this mechanism cannot be understated, as oncologists are now inducing nucleolar stress strategically in cancer cells as a potential anti-cancer therapy. We also summarize the human ribosomopathies, syndromes in which ribosome biogenesis or function are impaired leading to birth defects or bone narrow failures; the perplexing problem in the ribosomopathies is why only certain cells are affected despite the fact that the causative mutation is systemic. We then describe p53-independent nucleolar stress, first in yeast which lacks p53, and then in other model metazoans that lack MDM2, the critical E3 ubiquitin ligase that normally inactivates p53. Do these presumably ancient p53-independent nucleolar stress pathways remain latent in human cells? If they still exist, can we use them to target >50% of known human cancers that lack functional p53?
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Affiliation(s)
- Allison James
- a Department of Biological Sciences; Louisiana State University; Baton Rouge, LA USA
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31
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Morgunova V, Akulenko N, Radion E, Olovnikov I, Abramov Y, Olenina LV, Shpiz S, Kopytova DV, Georgieva SG, Kalmykova A. Telomeric repeat silencing in germ cells is essential for early development in Drosophila. Nucleic Acids Res 2015; 43:8762-73. [PMID: 26240377 PMCID: PMC4605298 DOI: 10.1093/nar/gkv775] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 07/21/2015] [Indexed: 12/03/2022] Open
Abstract
The germline-specific role of telomeres consists of chromosome end elongation and proper chromosome segregation during early developmental stages. Despite the crucial role of telomeres in germ cells, little is known about telomere biology in the germline. We analyzed telomere homeostasis in the Drosophila female germline and early embryos. A novel germline-specific function of deadenylase complex Ccr4-Not in the telomeric transcript surveillance mechanism is reported. Depletion of Ccr4-Not complex components causes strong derepression of the telomeric retroelement HeT-A in the germ cells, accompanied by elongation of the HeT-A poly(A) tail. Dysfunction of transcription factors Woc and Trf2, as well as RNA-binding protein Ars2, also results in the accumulation of excessively polyadenylated HeT-A transcripts in ovaries. Germline knockdowns of Ccr4-Not components, Woc, Trf2 and Ars2, lead to abnormal mitosis in early embryos, characterized by chromosome missegregation, centrosome dysfunction and spindle multipolarity. Moreover, the observed phenotype is accompanied by the accumulation of HeT-A transcripts around the centrosomes in early embryos, suggesting the putative relationship between overexpression of telomeric transcripts and mitotic defects. Our data demonstrate that Ccr4-Not, Woc, Trf2 and Ars2, components of different regulatory pathways, are required for telomere protection in the germline in order to guarantee normal development.
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Affiliation(s)
- Valeriya Morgunova
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, Russian Federation
| | - Natalia Akulenko
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, Russian Federation
| | - Elizaveta Radion
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, Russian Federation
| | - Ivan Olovnikov
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, Russian Federation
| | - Yuri Abramov
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, Russian Federation
| | - Ludmila V Olenina
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, Russian Federation
| | - Sergey Shpiz
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, Russian Federation
| | - Daria V Kopytova
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, Russian Federation
| | - Sofia G Georgieva
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, Russian Federation
| | - Alla Kalmykova
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, Russian Federation
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Arquint C, Gabryjonczyk AM, Nigg EA. Centrosomes as signalling centres. Philos Trans R Soc Lond B Biol Sci 2015; 369:rstb.2013.0464. [PMID: 25047618 DOI: 10.1098/rstb.2013.0464] [Citation(s) in RCA: 103] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Centrosomes-as well as the related spindle pole bodies (SPBs) of yeast-have been extensively studied from the perspective of their microtubule-organizing roles. Moreover, the biogenesis and duplication of these organelles have been the subject of much attention, and the importance of centrosomes and the centriole-ciliary apparatus for human disease is well recognized. Much less developed is our understanding of another facet of centrosomes and SPBs, namely their possible role as signalling centres. Yet, many signalling components, including kinases and phosphatases, have been associated with centrosomes and spindle poles, giving rise to the hypothesis that these organelles might serve as hubs for the integration and coordination of signalling pathways. In this review, we discuss a number of selected studies that bear on this notion. We cover different processes (cell cycle control, development, DNA damage response) and organisms (yeast, invertebrates and vertebrates), but have made no attempt to be comprehensive. This field is still young and although the concept of centrosomes and SPBs as signalling centres is attractive, it remains primarily a concept-in need of further scrutiny. We hope that this review will stimulate thought and experimentation.
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Affiliation(s)
- Christian Arquint
- Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland
| | | | - Erich A Nigg
- Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland
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33
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Takada S, Collins ER, Kurahashi K. The FHA domain determines Drosophila Chk2/Mnk localization to key mitotic structures and is essential for early embryonic DNA damage responses. Mol Biol Cell 2015; 26:1811-28. [PMID: 25808488 PMCID: PMC4436828 DOI: 10.1091/mbc.e14-07-1238] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Accepted: 03/17/2015] [Indexed: 01/23/2023] Open
Abstract
DNA damage responses, including mitotic centrosome inactivation, cell-cycle delay in mitosis, and nuclear dropping from embryo cortex, maintain genome integrity in syncytial Drosophila embryos. A conserved signaling kinase, Chk2, known as Mnk/Loki, is essential for the responses. Here we demonstrate that functional EGFP-Mnk expressed from a transgene localizes to the nucleus, centrosomes, interkinetochore/centromere region, midbody, and pseudocleavage furrows without DNA damage and in addition forms numerous foci/aggregates on mitotic chromosomes upon DNA damage. We expressed EGFP-tagged Mnk deletion or point mutation variants and investigated domain functions of Mnk in vivo. A triple mutation in the phosphopeptide-binding site of the forkhead-associated (FHA) domain disrupted normal Mnk localization except to the nucleus. The mutation also disrupted Mnk foci formation on chromosomes upon DNA damage. FHA mutations and deletion of the SQ/TQ-cluster domain (SCD) abolished Mnk transphosphorylations and autophosphorylations, indicative of kinase activation after DNA damage. A potent NLS was found at the C-terminus, which is required for normal Mnk function. We propose that the FHA domain in Mnk plays essential dual functions in mediating embryonic DNA damage responses by means of its phosphopeptide-binding ability: activating Mnk in the nucleus upon DNA damage and recruiting Mnk to multiple subcellular structures independently of DNA damage.
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Affiliation(s)
- Saeko Takada
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455
| | - Eric R Collins
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455
| | - Kayo Kurahashi
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455
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34
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Coordinating Cell Cycle Remodeling with Transcriptional Activation at the Drosophila MBT. Curr Top Dev Biol 2015; 113:113-48. [DOI: 10.1016/bs.ctdb.2015.06.002] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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35
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Iampietro C, Lécuyer E. Réponse aux dommages à l’ADN durant l’embryogenèse. Med Sci (Paris) 2014; 30:1070-3. [DOI: 10.1051/medsci/20143012005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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36
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37
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Drosophila RecQ5 is involved in proper progression of early spermatogenesis. Biochem Biophys Res Commun 2014; 452:1071-7. [PMID: 25245292 DOI: 10.1016/j.bbrc.2014.09.051] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Accepted: 09/12/2014] [Indexed: 11/22/2022]
Abstract
RecQ5, a member of the conserved RecQ DNA helicase family, is required for the maintenance of genome stability. The human RECQL5 gene is expressed ubiquitously in almost all tissues, with strong expression in the testes (Shimamoto et al., 2000). However, it remains to be elucidated in which cells RecQ5 is expressed and how RecQ5 functions in the testes. In this present study we analyzed the expression of RecQ5 in Drosophila testes. The RecQ5 protein was specifically expressed in germline cells in larval, pupal, and adult testes. Drosophila RecQ5 was localized in nuclei of male germline stem cells, spermatogoniablasts, spermatogonia, and early spermatocytes. As growth of the early spermatocyte proceeded, the amount of RecQ5 increased in the nuclei. However, before maturation of the spermatocyte, the level of RecQ5 declined. Thus, RecQ5 expression was regulated. Furthermore, we compared recq5 mutant testes with the wild-type ones. The most conspicuous alterations were swelling of the apical region of and an increase in the number of spermatocytes in the recq5 testis, suggesting a relative accumulation of spermatocytes in the recq5 mutant testes. Therefore, Drosophila RecQ5 may contribute to the proper progression from germline stem cells to spermatocytes for maintenance of genome stability.
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38
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Abstract
Cells with irreparable genomic damage pose a problem for development and must be eliminated to prevent disease. Reporting in this issue of Developmental Cell, Iampietro et al. (2014) describe a mechanism in Drosophila that removes damaged nuclei from syncytial blastoderm embryos via DNA damage checkpoint kinase-mediated retention of specific mRNAs within the nucleus.
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Affiliation(s)
- William F Marzluff
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599, USA; Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599, USA; Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, NC 27599, USA.
| | - Robert J Duronio
- Departments of Biology and Genetics, University of North Carolina, Chapel Hill, NC 27599, USA; Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599, USA; Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, NC 27599, USA.
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39
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TCTP directly regulates ATM activity to control genome stability and organ development in Drosophila melanogaster. Nat Commun 2014; 4:2986. [PMID: 24352200 DOI: 10.1038/ncomms3986] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Accepted: 11/21/2013] [Indexed: 02/03/2023] Open
Abstract
Translationally controlled tumour protein (TCTP) is implicated in growth regulation and cancer. Recently, human TCTP has been suggested to play a role in the DNA damage response by forming a complex with ataxia telangiectasia-mutated (ATM) kinase . However, the exact nature of this interaction and its roles in vivo remained unclear. Here, we utilize Drosophila as an animal model to study the nuclear function of Drosophila TCTP (dTCTP). dTCTP mutants show increased radiation sensitivity during development as well as strong genetic interaction with dATM mutations, resulting in severe defects in developmental timing, organ size and chromosome stability. We identify Drosophila ATM (dATM) as a direct binding partner of dTCTP and describe a mechanistic basis for dATM activation by dTCTP. Altogether, this study provides the first in vivo evidence for direct modulation of dATM activity by dTCTP in the control of genome stability and organ development.
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40
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Atikukke G, Albosta P, Zhang H, Finley RL. A role for Drosophila Cyclin J in oogenesis revealed by genetic interactions with the piRNA pathway. Mech Dev 2014; 133:64-76. [PMID: 24946235 DOI: 10.1016/j.mod.2014.06.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2013] [Revised: 06/05/2014] [Accepted: 06/06/2014] [Indexed: 11/29/2022]
Abstract
Cyclin J (CycJ) is a poorly characterized member of the Cyclin superfamily of cyclin-dependent kinase regulators, many of which regulate the cell cycle or transcription. Although CycJ is conserved in metazoans its cellular function has not been identified and no mutant defects have been described. In Drosophila, CycJ transcript is present primarily in ovaries and very early embryos, suggesting a role in one or both of these tissues. The CycJ gene (CycJ) lies immediately downstream of armitage (armi), a gene involved in the Piwi-associated RNA (piRNA) pathways that are required for silencing transposons in the germline and adjacent somatic cells. Mutations in armi result in oogenesis defects but a role for CycJ in oogenesis has not been defined. Here we assessed oogenesis in CycJ mutants in the presence or absence of mutations in armi or other piRNA pathway genes. CycJ null ovaries appeared normal, indicating that CycJ is not essential for oogenesis under normal conditions. In contrast, armi null ovaries produced only two egg chambers per ovariole and the eggs had severe axis specification defects, as observed previously for armi and other piRNA pathway mutants. Surprisingly, the CycJ armi double mutant failed to produce any mature eggs. The double null ovaries generally had only one egg chamber per ovariole and the egg chambers frequently contained an overabundance of differentiated germline cells. Production of these compound egg chambers could be suppressed with CycJ transgenes but not with mutations in the checkpoint gene mnk, which suppress oogenesis defects in armi mutants. The CycJ null showed similar genetic interactions with the germline and somatic piRNA pathway gene piwi, and to a lesser extent with aubergine (aub), a member of the germline-specific piRNA pathway. The strong genetic interactions between CycJ and piRNA pathway genes reveal a role for CycJ in early oogenesis. Our results suggest that CycJ is required to regulate egg chamber production or maturation when piRNA pathways are compromised.
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Affiliation(s)
- Govindaraja Atikukke
- Department of Biochemistry and Molecular Biology, Wayne State University School of Medicine, Detroit, MI 48201, USA.
| | - Paul Albosta
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI 48201, USA.
| | - Huamei Zhang
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI 48201, USA.
| | - Russell L Finley
- Department of Biochemistry and Molecular Biology, Wayne State University School of Medicine, Detroit, MI 48201, USA; Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI 48201, USA.
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41
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Luna, a Drosophila KLF6/KLF7, is maternally required for synchronized nuclear and centrosome cycles in the preblastoderm embryo. PLoS One 2014; 9:e96933. [PMID: 24915236 PMCID: PMC4051582 DOI: 10.1371/journal.pone.0096933] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 04/11/2014] [Indexed: 11/20/2022] Open
Abstract
Krüppel like factors (KLFs) are conserved transcription factors that have been implicated in many developmental processes including differentiation, organ patterning, or regulation of stem cell pluripotency. We report the generation and analysis of loss-of-function mutants of Drosophila Klf6/7, the luna gene. We demonstrate that luna mutants are associated with very early embryonic defects prior to cellularization at the syncytial stage and cause DNA separation defects during the rapid mitotic cycles resulting in un-coupled DNA and centrosome cycles. These defects manifest themselves, both in animals that are maternally homozygous and heterozygous mutant. Surprisingly, luna is only required during the syncytial stages and not later in development, suggesting that the DNA segregation defect is linked to centrosomes, since centrosomes are dispensable for later cell divisions.
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42
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Iampietro C, Bergalet J, Wang X, Cody NAL, Chin A, Lefebvre FA, Douziech M, Krause HM, Lécuyer E. Developmentally regulated elimination of damaged nuclei involves a Chk2-dependent mechanism of mRNA nuclear retention. Dev Cell 2014; 29:468-81. [PMID: 24835465 DOI: 10.1016/j.devcel.2014.03.025] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Revised: 12/18/2013] [Accepted: 03/31/2014] [Indexed: 11/25/2022]
Abstract
The faithful execution of embryogenesis relies on the ability of organisms to respond to genotoxic stress and to eliminate defective cells that could otherwise compromise viability. In syncytial-stage Drosophila embryos, nuclei with excessive DNA damage undergo programmed elimination through an as-yet poorly understood process of nuclear fallout at the midblastula transition. We show that this involves a Chk2-dependent mechanism of mRNA nuclear retention that is induced by DNA damage and prevents the translation of specific zygotic mRNAs encoding key mitotic, cytoskeletal, and nuclear proteins required to maintain nuclear viability. For histone messages, we show that nuclear retention involves Chk2-mediated inactivation of the Drosophila stem loop binding protein (SLBP), the levels of which are specifically depleted in damaged nuclei following Chk2 phosphorylation, an event that contributes to nuclear fallout. These results reveal a layer of regulation within the DNA damage surveillance systems that safeguard genome integrity in eukaryotes.
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Affiliation(s)
- Carole Iampietro
- Institut de Recherches Cliniques de Montréal (IRCM), Montréal, QC H2W 1R7, Canada
| | - Julie Bergalet
- Institut de Recherches Cliniques de Montréal (IRCM), Montréal, QC H2W 1R7, Canada
| | - Xiaofeng Wang
- Institut de Recherches Cliniques de Montréal (IRCM), Montréal, QC H2W 1R7, Canada
| | - Neal A L Cody
- Institut de Recherches Cliniques de Montréal (IRCM), Montréal, QC H2W 1R7, Canada
| | - Ashley Chin
- Institut de Recherches Cliniques de Montréal (IRCM), Montréal, QC H2W 1R7, Canada
| | - Fabio Alexis Lefebvre
- Institut de Recherches Cliniques de Montréal (IRCM), Montréal, QC H2W 1R7, Canada; Département de Biochimie, Université de Montréal, Montréal, QC H3T 1J4, Canada
| | - Mélanie Douziech
- Institut de Recherches Cliniques de Montréal (IRCM), Montréal, QC H2W 1R7, Canada
| | - Henry M Krause
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON M5S 3E1, Canada
| | - Eric Lécuyer
- Institut de Recherches Cliniques de Montréal (IRCM), Montréal, QC H2W 1R7, Canada; Département de Biochimie, Université de Montréal, Montréal, QC H3T 1J4, Canada; Division of Experimental Medicine, McGill University, Montréal, QC H3A 1A3, Canada.
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43
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Wallace HA, Merkle JA, Yu MC, Berg TG, Lee E, Bosco G, Lee LA. TRIP/NOPO E3 ubiquitin ligase promotes ubiquitylation of DNA polymerase η. Development 2014; 141:1332-41. [PMID: 24553286 DOI: 10.1242/dev.101196] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We previously identified a Drosophila maternal effect-lethal mutant named 'no poles' (nopo). Embryos from nopo females undergo mitotic arrest with barrel-shaped, acentrosomal spindles during the rapid cycles of syncytial embryogenesis because of activation of a Chk2-mediated DNA checkpoint. NOPO is the Drosophila homolog of human TNF receptor associated factor (TRAF)-interacting protein (TRIP), which has been implicated in TNF signaling. NOPO and TRIP contain RING domains closely resembling those of known E3 ubiquitin ligases. We herein sought to elucidate the mechanism by which TRIP/NOPO promotes genomic stability by performing a yeast two-hybrid screen to identify potential substrates/interactors. We identified members of the Y-family of DNA polymerases that facilitate replicative bypass of damaged DNA (translesion synthesis) as TRIP interactors. We show that TRIP and NOPO co-immunoprecipitate with human and Drosophila Polη, respectively, from cultured cells. We generated a null mutation in Drosophila Polη (dPolη) and found that dPolη-derived embryos have increased sensitivity to ultraviolet irradiation and exhibit nopo-like mitotic spindle defects. dPolη and nopo interact genetically in that overexpression of dPolη in hypomorphic nopo-derived embryos suppresses nopo phenotypes. We observed enhanced ubiquitylation of Polη by TRIP and NOPO E3 ligases in human cells and Drosophila embryos, respectively, and show that TRIP promotes hPolη localization to nuclear foci in human cells. We present a model in which TRIP/NOPO ubiquitylates Polη to positively regulate its activity in translesion synthesis.
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Affiliation(s)
- Heather A Wallace
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, U-4225 Medical Research Building III, 465 21st Avenue South, Nashville, TN 37232-8240, USA
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Shim HJ, Lee EM, Nguyen LD, Shim J, Song YH. High-dose irradiation induces cell cycle arrest, apoptosis, and developmental defects during Drosophila oogenesis. PLoS One 2014; 9:e89009. [PMID: 24551207 PMCID: PMC3923870 DOI: 10.1371/journal.pone.0089009] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Accepted: 01/14/2014] [Indexed: 11/18/2022] Open
Abstract
Ionizing radiation (IR) treatment induces a DNA damage response, including cell cycle arrest, DNA repair, and apoptosis in metazoan somatic cells. Because little has been reported in germline cells, we performed a temporal analysis of the DNA damage response utilizing Drosophila oogenesis as a model system. Oogenesis in the adult Drosophila female begins with the generation of 16-cell cyst by four mitotic divisions of a cystoblast derived from the germline stem cells. We found that high-dose irradiation induced S and G2 arrests in these mitotically dividing germline cells in a grp/Chk1- and mnk/Chk2-dependent manner. However, the upstream kinase mei-41, Drosophila ATR ortholog, was required for the S-phase checkpoint but not for the G2 arrest. As in somatic cells, mnk/Chk2 and dp53 were required for the major cell death observed in early oogenesis when oocyte selection and meiotic recombination occurs. Similar to the unscheduled DNA double-strand breaks (DSBs) generated from defective repair during meiotic recombination, IR-induced DSBs produced developmental defects affecting the spherical morphology of meiotic chromosomes and dorsal-ventral patterning. Moreover, various morphological abnormalities in the ovary were detected after irradiation. Most of the IR-induced defects observed in oogenesis were reversible and were restored between 24 and 96 h after irradiation. These defects in oogenesis severely reduced daily egg production and the hatch rate of the embryos of irradiated female. In summary, irradiated germline cells induced DSBs, cell cycle arrest, apoptosis, and developmental defects resulting in reduction of egg production and defective embryogenesis.
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Affiliation(s)
- Hee Jin Shim
- Ilsong Institute of Life Science, Hallym University, Anyang, Gyeonggi-do, Korea
| | - Eun-Mi Lee
- Ilsong Institute of Life Science, Hallym University, Anyang, Gyeonggi-do, Korea
| | - Long Duy Nguyen
- Ilsong Institute of Life Science, Hallym University, Anyang, Gyeonggi-do, Korea
| | - Jaekyung Shim
- Department of Molecular Biology, Sejong University, Seoul, Korea
| | - Young-Han Song
- Ilsong Institute of Life Science, Hallym University, Anyang, Gyeonggi-do, Korea
- * E-mail:
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Zou J, Zhang D, Qin G, Chen X, Wang H, Zhang D. BRCA1 and FancJ cooperatively promote interstrand crosslinker induced centrosome amplification through the activation of polo-like kinase 1. Cell Cycle 2014; 13:3685-97. [PMID: 25483079 PMCID: PMC4612125 DOI: 10.4161/15384101.2014.964973] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Revised: 09/08/2014] [Accepted: 09/09/2014] [Indexed: 12/15/2022] Open
Abstract
DNA damage response (DDR) and the centrosome cycle are 2 of the most critical cellular processes affecting the genome stability in animal cells. Yet the cross-talks between DDR and the centrosome are poorly understood. Here we showed that deficiency of the breast cancer 1, early onset gene (BRCA1) induces centrosome amplification in non-stressed cells as previously reported while attenuating DNA damage-induced centrosome amplification (DDICA) in cells experiencing prolonged genotoxic stress. Mechanistically, the function of BRCA1 in promoting DDICA is through binding and recruiting polo-like kinase 1 (PLK1) to the centrosome. In a recent study, we showed that FancJ also suppresses centrosome amplification in non-stressed cells while promoting DDICA in both hydroxyurea and mitomycin C treated cells. FancJ is a key component of the BRCA1 B-complex. Here, we further demonstrated that, in coordination with BRCA1, FancJ promotes DDICA by recruiting both BRCA1 and PLK1 to the centrosome in the DNA damaged cells. Thus, we have uncovered a novel role of BRCA1 and FancJ in the regulation of DDICA. Dysregulation of DDR or centrosome cycle leads to aneuploidy, which is frequently seen in both solid and hematological cancers. BRCA1 and FancJ are known tumor suppressors and have well-recognized functions in DNA damage checkpoint and DNA repair. Together with our recent findings, we demonstrated here that BRCA1 and FancJ also play an important role in centrosome cycle especially in DDICA. DDICA is thought to be an alternative fail-safe mechanism to prevent cells experiencing severe DNA damage from becoming carcinogenic. Therefore, BRCA1 and FancJ are potential liaisons linking early DDR with the DDICA. We propose that together with their functions in DDR, the role of BRCA1 and FancJ in the activation of DDICA is also crucial for their tumor suppression functions in vivo.
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Key Words
- ATM, ataxia telangiectasia mutated
- ATR, ataxia telangiectasia Rad3-related
- BRCA1
- BRCA1, breast cancer gene 1
- CIN, chromosome instability
- DDICA, DNA damage induced centrosome amplification
- DDR, DNA damage response
- DNA damage response
- FancJ
- GFP, green fluorescent protein
- HR, homologous recombination
- HU, hydroxyurea
- ICL, interstrand cross-linkers
- MIN, microsatellite instability
- MMC, mitomycin C
- MT, microtubule
- PCM, pericentriolar materials
- PLK1
- PLK1, Polo-like kinase 1
- UTR, untranslated region
- WCL, whole-cell lysate
- centrosome amplification
- interstrand cross-link
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Affiliation(s)
- Jianqiu Zou
- Basic Biomedical Science Division; Sanford School of Medicine; University of South Dakota; Vermillion, SD USA
| | - Deli Zhang
- WeiFang Medical University; WeiFang, Shandong, China
| | - Guang Qin
- Department of Oncology; Central Hospital of TaiAn; TaiAn, Shandong, China
| | - Xiangming Chen
- Department of Oncology; Central Hospital of TaiAn; TaiAn, Shandong, China
| | - Hongmin Wang
- Basic Biomedical Science Division; Sanford School of Medicine; University of South Dakota; Vermillion, SD USA
| | - Dong Zhang
- Basic Biomedical Science Division; Sanford School of Medicine; University of South Dakota; Vermillion, SD USA
- Department of Biomedical Sciences; College of Osteopathic Medicine; New York Institute of Technology; Old Westbury, NY USA
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Amorphous no more: subdiffraction view of the pericentriolar material architecture. Trends Cell Biol 2013; 24:188-97. [PMID: 24268653 DOI: 10.1016/j.tcb.2013.10.001] [Citation(s) in RCA: 103] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Revised: 09/30/2013] [Accepted: 10/03/2013] [Indexed: 12/12/2022]
Abstract
The centrosome influences the shape, orientation and activity of the microtubule cytoskeleton. The pericentriolar material (PCM), determines this functionality by providing a dynamic platform for nucleating microtubules and acts as a nexus for molecular signaling. Although great strides have been made in understanding PCM activity, its diffraction-limited size and amorphous appearance on electron microscopy (EM) have limited analysis of its high-order organization. Here, we outline current knowledge of PCM architecture and assembly, emphasizing recent super-resolution imaging studies that revealed the PCM has a layered structure made of fibers and matrices conserved from flies to humans. Notably, these studies debunk the long-standing view of an amorphous PCM and provide a paradigm to dissect the supramolecular organization of organelles in cells.
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Mani SR, Megosh H, Lin H. PIWI proteins are essential for early Drosophila embryogenesis. Dev Biol 2013; 385:340-9. [PMID: 24184635 DOI: 10.1016/j.ydbio.2013.10.017] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Revised: 09/23/2013] [Accepted: 10/20/2013] [Indexed: 11/16/2022]
Abstract
PIWI proteins, a subfamily of the ARGONAUTE/PIWI protein family, have been implicated in transcriptional and posttranscriptional gene regulation and transposon silencing mediated by small non-coding RNAs, especially piRNAs. Although these proteins are known to be required for germline development, their somatic function remains elusive. Here, we examine the maternal function of all three PIWI proteins in Drosophila; Piwi, Aubergine (Aub) and Argonaute3 (Ago3) during early embryogenesis. In syncytial embryos, Piwi displays an embryonic stage-dependent localization pattern. Piwi is localized in the cytoplasm during mitotic cycles 1-10. Between cycles 11 and 14, Piwi remains in the cytoplasm during mitosis but moves into the somatic nucleus during interphase. Beyond cycle 14, it stays in the nucleus. Aub and Ago3 are diffusely cytoplasmic from cycle 1 to 14. Embryos maternally depleted of any one of the three PIWI proteins display severe mitotic defects, including abnormal chromosome and nuclear morphology, cell cycle arrest, asynchronous nuclear division and aberrant nuclear migration. Furthermore, all three PIWI proteins are required for the assembly of mitotic machinery and progression through mitosis. Embryos depleted of maternal PIWI proteins also exhibit chromatin organization abnormalities. These observations indicate that maternal Piwi, Aub and Ago3 play a critical role in the maintenance of chromatin structure and cell cycle progression during early embryogenesis, with compromised chromatin integrity as a possible cause of the observed mitotic defects. Our study demonstrates the essential function of PIWI proteins in the first phase of somatic development.
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Affiliation(s)
- Sneha Ramesh Mani
- Yale Stem Cell Center and Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06509, USA
| | - Heather Megosh
- Department of Cell Biology, Duke University Medical School, Durham, NC 27710, USA
| | - Haifan Lin
- Yale Stem Cell Center and Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06509, USA; Department of Cell Biology, Duke University Medical School, Durham, NC 27710, USA.
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Poulton JS, Mu FW, Roberts DM, Peifer M. APC2 and Axin promote mitotic fidelity by facilitating centrosome separation and cytoskeletal regulation. Development 2013; 140:4226-36. [PMID: 24026117 DOI: 10.1242/dev.094425] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
To ensure the accurate transmission of genetic material, chromosome segregation must occur with extremely high fidelity. Segregation errors lead to chromosomal instability (CIN), with deleterious consequences. Mutations in the tumor suppressor adenomatous polyposis coli (APC) initiate most colon cancers and have also been suggested to promote disease progression through increased CIN, but the mechanistic role of APC in preventing CIN remains controversial. Using fly embryos as a model, we investigated the role of APC proteins in CIN. Our findings suggest that APC2 loss leads to increased rates of chromosome segregation error. This occurs through a cascade of events beginning with incomplete centrosome separation leading to failure to inhibit formation of ectopic cleavage furrows, which result in mitotic defects and DNA damage. We test several hypotheses related to the mechanism of action of APC2, revealing that APC2 functions at the embryonic cortex with several protein partners, including Axin, to promote mitotic fidelity. Our in vivo data demonstrate that APC2 protects genome stability by modulating mitotic fidelity through regulation of the cytoskeleton.
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Affiliation(s)
- John S Poulton
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA
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Whitfield ZJ, Chisholm J, Hawley RS, Orr-Weaver TL. A meiosis-specific form of the APC/C promotes the oocyte-to-embryo transition by decreasing levels of the Polo kinase inhibitor matrimony. PLoS Biol 2013; 11:e1001648. [PMID: 24019759 PMCID: PMC3760765 DOI: 10.1371/journal.pbio.1001648] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Accepted: 07/23/2013] [Indexed: 11/23/2022] Open
Abstract
During the oocyte-to-embryo transition in Drosophila, degradation of the Polo kinase inhibitor, Matrimony, depends on Cortex, a meiosis-specific form of the Anaphase Promoting Complex/Cyclosome that is required for the oocyte's normal transition from meiosis to mitosis. Oocytes are stockpiled with proteins and mRNA that are required to drive the initial mitotic divisions of embryogenesis. But are there proteins specific to meiosis whose levels must be decreased to begin embryogenesis properly? The Drosophila protein Cortex (Cort) is a female, meiosis-specific activator of the Anaphase Promoting Complex/Cyclosome (APC/C), an E3 ubiquitin ligase. We performed immunoprecipitation of Cortex followed by mass spectrometry, and identified the Polo kinase inhibitor Matrimony (Mtrm) as a potential interactor with Cort. In vitro binding assays showed Mtrm and Cort can bind directly. We found Mtrm protein levels to be reduced dramatically during the oocyte-to-embryo transition, and this downregulation did not take place in cort mutant eggs, consistent with Mtrm being a substrate of APCCort. We showed that Mtrm is subject to APCCort-mediated proteasomal degradation and have identified a putative APC/C recognition motif in Mtrm that when mutated partially stabilized the protein in the embryo. Furthermore, overexpression of Mtrm in the early embryo caused aberrant nuclear divisions and developmental defects, and these were enhanced by decreasing levels of active Polo. These data indicate APCCort ubiquitylates Mtrm at the oocyte-to-embryo transition, thus preventing excessive inhibition of Polo kinase activity due to Mtrm's presence. Despite their many differences, the meiotic and mitotic divisions of the early embryo take place within the same cytoplasmic space. The oocyte-to-embryo transition is the process by which an oocyte, which initially undergoes meiosis, becomes “adapted” to support the rapid mitotic divisions of embryogenesis. This involves fertilization as well as the stockpiling of proteins and mRNA for the transcriptionally silent early embryo. The Anaphase Promoting Complex/Cyclosome (APC/C) is a large protein complex that is active during both mitosis and meiosis and is responsible for targeting certain proteins for degradation. The discovery of the existence of APC/C activators that are present only during meiosis hinted at the possibility that this complex also functions to regulate protein degradation during the oocyte-to-embryo transition. Here we study Cortex, a female- and meiosis-specific activator of the APC/C in the fruit fly Drosophila melanogaster. We find that Cortex activity is necessary for the degradation of Matrimony, a key regulator of female meiosis in Drosophila. Matrimony itself inhibits Polo kinase, another important regulator of both mitosis and meiosis that also functions in chromosome segregation, centrosome dynamics, and cytokinesis. When excess Matrimony protein is not removed from the early embryo, developmental defects arise. Together our findings demonstrate that the precise regulation of Matrimony levels in the egg is necessary for the switch from meiosis to mitosis.
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Affiliation(s)
- Zachary J. Whitfield
- Whitehead Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Jennifer Chisholm
- Stowers Institute for Medical Research, Kansas City, Missouri, United States of America
| | - R. Scott Hawley
- Stowers Institute for Medical Research, Kansas City, Missouri, United States of America
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas, United States of America
| | - Terry L. Orr-Weaver
- Whitehead Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- * E-mail:
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Zou J, Tian F, Li J, Pickner W, Long M, Rezvani K, Wang H, Zhang D. FancJ regulates interstrand crosslinker induced centrosome amplification through the activation of polo-like kinase 1. Biol Open 2013; 2:1022-31. [PMID: 24167712 PMCID: PMC3798185 DOI: 10.1242/bio.20135801] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Accepted: 07/03/2013] [Indexed: 01/05/2023] Open
Abstract
DNA damage response (DDR) and the centrosome cycle are two of the most critical processes for maintaining a stable genome in animals. Sporadic evidence suggests a connection between these two processes. Here, we report our findings that six Fanconi Anemia (FA) proteins, including FancI and FancJ, localize to the centrosome. Intriguingly, we found that the localization of FancJ to the mother centrosome is stimulated by a DNA interstrand crosslinker, Mitomycin C (MMC). We further show that, in addition to its role in interstrand crosslinking (ICL) repair, FancJ also regulates the normal centrosome cycle as well as ICL induced centrosome amplification by activating the polo-like kinase 1 (PLK1). We have uncovered a novel function of FancJ in centrosome biogenesis and established centrosome amplification as an integral part of the ICL response.
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Affiliation(s)
- Jianqiu Zou
- Basic Biomedical Science Division, Sanford School of Medicine, University of South Dakota , Vermillion, South Dakota, 57069 , USA
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