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Cooper JC, Lukacs A, Reich S, Schauer T, Imhof A, Phadnis N. Altered Localization of Hybrid Incompatibility Proteins in Drosophila. Mol Biol Evol 2020; 36:1783-1792. [PMID: 31038678 PMCID: PMC6657725 DOI: 10.1093/molbev/msz105] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Understanding the molecular basis of hybrid incompatibilities is a fundamental pursuit in evolutionary genetics. In crosses between Drosophila melanogaster females and Drosophila simulans males, an interaction between at least three genes is necessary for hybrid male lethality: Hmr mel, Lhr sim, and gfzf sim. Although HMR and LHR physically bind each other and function together in a single complex, the connection between gfzf and either of these proteins remains mysterious. Here, we show that GFZF localizes to many regions of the genome in both D. melanogaster and D. simulans, including at telomeric retrotransposon repeats. We find that GFZF localization at telomeres is significantly different between these two species, reflecting the rapid evolution of telomeric retrotransposon copy number composition between the two species. Next, we show that GFZF and HMR normally do not colocalize in D. melanogaster. In interspecies hybrids, however, HMR shows extensive mis-localization to GFZF sites, thus uncovering a new molecular interaction between these hybrid incompatibility factors. We find that spreading of HMR to GFZF sites requires gfzf sim but not Lhr sim, suggesting distinct roles for these factors in the hybrid incompatibility. Finally, we find that overexpression of HMR and LHR within species is sufficient to mis-localize HMR to GFZF binding sites, indicating that HMR has a natural low affinity for GFZF sites. Together, these studies provide the first insights into the different properties of gfzf between D. melanogaster and D. simulans, and uncover a molecular interaction between gfzf and Hmr in the form of altered protein localization.
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Affiliation(s)
| | - Andrea Lukacs
- Faculty of Medicine, Institute for Molecular Biology, Biomedical Center (BMC), LMU Munich, Germany
| | - Shelley Reich
- School of Biological Sciences, University of Utah, Salt Lake City, UT
| | - Tamas Schauer
- Faculty of Medicine, Institute for Molecular Biology, Biomedical Center (BMC), LMU Munich, Germany
| | - Axel Imhof
- Faculty of Medicine, Institute for Molecular Biology, Biomedical Center (BMC), LMU Munich, Germany.,Center for Integrated Protein Science Munich (CIPSM), Ludwig-Maximilians-Universität Müchen, Munich, Germany
| | - Nitin Phadnis
- School of Biological Sciences, University of Utah, Salt Lake City, UT
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Smith GA, Lin TH, Sheehan AE, Van der Goes van Naters W, Neukomm LJ, Graves HK, Bis-Brewer DM, Züchner S, Freeman MR. Glutathione S-Transferase Regulates Mitochondrial Populations in Axons through Increased Glutathione Oxidation. Neuron 2019; 103:52-65.e6. [PMID: 31101394 PMCID: PMC6616599 DOI: 10.1016/j.neuron.2019.04.017] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 12/13/2018] [Accepted: 04/10/2019] [Indexed: 01/14/2023]
Abstract
Mitochondria are essential in long axons to provide metabolic support and sustain neuron integrity. A healthy mitochondrial pool is maintained by biogenesis, transport, mitophagy, fission, and fusion, but how these events are regulated in axons is not well defined. Here, we show that the Drosophila glutathione S-transferase (GST) Gfzf prevents mitochondrial hyperfusion in axons. Gfzf loss altered redox balance between glutathione (GSH) and oxidized glutathione (GSSG) and initiated mitochondrial fusion through the coordinated action of Mfn and Opa1. Gfzf functioned epistatically with the thioredoxin peroxidase Jafrac1 and the thioredoxin reductase 1 TrxR-1 to regulate mitochondrial dynamics. Altering GSH:GSSG ratios in mouse primary neurons in vitro also induced hyperfusion. Mitochondrial changes caused deficits in trafficking, the metabolome, and neuronal physiology. Changes in GSH and oxidative state are associated with neurodegenerative diseases like Alzheimer's. Our demonstration that GSTs are key in vivo regulators of axonal mitochondrial length and number provides a potential mechanistic link.
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Affiliation(s)
- Gaynor A Smith
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA 01605, USA; Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA; UK Dementia Research Institute, School of Medicine, Cardiff University, Cardiff CF24 4HQ, UK.
| | - Tzu-Huai Lin
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA 01605, USA; Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Amy E Sheehan
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA 01605, USA; Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | | | - Lukas J Neukomm
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA 01605, USA; Department of Fundamental Neurosciences, University of Lausanne, 1005 Lausanne VD, Switzerland
| | - Hillary K Graves
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Dana M Bis-Brewer
- John P. Hussman Institute for Human Genomics, University of Miami, Miami, FL, USA; Dr. John T. Macdonald Foundation Department of Human Genetics, University of Miami, Miami, FL, USA
| | - Stephan Züchner
- John P. Hussman Institute for Human Genomics, University of Miami, Miami, FL, USA; Dr. John T. Macdonald Foundation Department of Human Genetics, University of Miami, Miami, FL, USA
| | - Marc R Freeman
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA 01605, USA; Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA
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Moving Speciation Genetics Forward: Modern Techniques Build on Foundational Studies in Drosophila. Genetics 2018; 207:825-842. [PMID: 29097397 DOI: 10.1534/genetics.116.187120] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 06/23/2017] [Indexed: 12/12/2022] Open
Abstract
The question of how new species evolve has been examined at every level, from macroevolutionary patterns of diversification to molecular population genetic analyses of specific genomic regions between species pairs. Drosophila has been at the center of many of these research efforts. Though our understanding of the speciation process has grown considerably over the past few decades, very few genes have been identified that contribute to barriers to reproduction. The development of advanced molecular genetic and genomic methods provides promising avenues for the rapid discovery of more genes that contribute to speciation, particularly those involving prezygotic isolation. The continued expansion of tools and resources, especially for species other than Drosophila melanogaster, will be most effective when coupled with comparative approaches that reveal the genetic basis of reproductive isolation across a range of divergence times. Future research programs in Drosophila have high potential to answer long-standing questions in speciation. These include identifying the selective forces that contribute to divergence between populations and the genetic basis of traits that cause reproductive isolation. The latter can be expanded upon to understand how the genetic basis of reproductive isolation changes over time and whether certain pathways and genes are more commonly involved.
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GFZF, a Glutathione S-Transferase Protein Implicated in Cell Cycle Regulation and Hybrid Inviability, Is a Transcriptional Coactivator. Mol Cell Biol 2018; 38:MCB.00476-17. [PMID: 29158293 DOI: 10.1128/mcb.00476-17] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Accepted: 11/10/2017] [Indexed: 01/11/2023] Open
Abstract
The core promoters of protein-encoding genes play a central role in regulating transcription. M1BP is a transcriptional activator that associates with a core promoter element known as Motif 1 that resides at thousands of genes in Drosophila To gain insight into how M1BP functions, we identified an interacting protein called GFZF. GFZF had been previously identified in genetic screens for factors involved in maintenance of hybrid inviability, the G2-M DNA damage checkpoint, and RAS/mitogen-activated protein kinase (MAPK) signaling, but its contribution to these processes was unknown. Here, we show that GFZF resides in the nucleus and functions as a transcriptional coactivator. In addition, we show that GFZF is a glutathione S-transferase (GST). Thus, GFZF is the first transcriptional coactivator with intrinsic GST activity, and its identification as a transcriptional coactivator provides an explanation for its role in numerous biological processes.
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Abstract
Uncovering the genetic and molecular basis of barriers to gene flow between populations is key to understanding how new species are born. Intrinsic postzygotic reproductive barriers such as hybrid sterility and hybrid inviability are caused by deleterious genetic interactions known as hybrid incompatibilities. The difficulty in identifying these hybrid incompatibility genes remains a rate-limiting step in our understanding of the molecular basis of speciation. We recently described how whole genome sequencing can be applied to identify hybrid incompatibility genes, even from genetically terminal hybrids. Using this approach, we discovered a new hybrid incompatibility gene, gfzf, between Drosophila melanogaster and Drosophila simulans, and found that it plays an essential role in cell cycle regulation. Here, we discuss the history of the hunt for incompatibility genes between these species, discuss the molecular roles of gfzf in cell cycle regulation, and explore how intragenomic conflict drives the evolution of fundamental cellular mechanisms that lead to the developmental arrest of hybrids.
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Affiliation(s)
- Jacob C Cooper
- a Department of Biology , University of Utah , Salt Lake City , UT , USA
| | - Nitin Phadnis
- a Department of Biology , University of Utah , Salt Lake City , UT , USA
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Phadnis N, Baker EP, Cooper JC, Frizzell KA, Hsieh E, de la Cruz AFA, Shendure J, Kitzman JO, Malik HS. An essential cell cycle regulation gene causes hybrid inviability in Drosophila. Science 2016; 350:1552-5. [PMID: 26680200 DOI: 10.1126/science.aac7504] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Speciation, the process by which new biological species arise, involves the evolution of reproductive barriers, such as hybrid sterility or inviability between populations. However, identifying hybrid incompatibility genes remains a key obstacle in understanding the molecular basis of reproductive isolation. We devised a genomic screen, which identified a cell cycle-regulation gene as the cause of male inviability in hybrids resulting from a cross between Drosophila melanogaster and D. simulans. Ablation of the D. simulans allele of this gene is sufficient to rescue the adult viability of hybrid males. This dominantly acting cell cycle regulator causes mitotic arrest and, thereby, inviability of male hybrid larvae. Our genomic method provides a facile means to accelerate the identification of hybrid incompatibility genes in other model and nonmodel systems.
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Affiliation(s)
- Nitin Phadnis
- Department of Biology, University of Utah, Salt Lake City, UT 84112, USA.
| | - EmilyClare P Baker
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Jacob C Cooper
- Department of Biology, University of Utah, Salt Lake City, UT 84112, USA
| | | | - Emily Hsieh
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | | | - Jay Shendure
- Genome Sciences, University of Washington, Seattle, WA 98195, USA. Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195, USA
| | - Jacob O Kitzman
- Genome Sciences, University of Washington, Seattle, WA 98195, USA. Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Harmit S Malik
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA. Howard Hughes Medical Institute, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA.
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Nallamothu G, Dammai V, Hsu T. Developmental function of Nm23/awd: a mediator of endocytosis. Mol Cell Biochem 2009; 329:35-44. [PMID: 19373545 PMCID: PMC2721904 DOI: 10.1007/s11010-009-0112-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2009] [Accepted: 04/02/2009] [Indexed: 10/20/2022]
Abstract
The metastasis suppressor gene Nm23 is highly conserved from yeast to human, implicating a critical developmental function. Studies in cultured mammalian cells have identified several potential functions, but many have not been directly verified in vivo. Here, we summarize the studies on the Drosophila homolog of the Nm23 gene, named a bnormal w ing d iscs (awd), which shares 78% amino acid identity with the human Nm23-H1 and H2 isoforms. These studies confirmed that awd gene encodes a nucleoside diphosphate kinase, and provided strong evidence of a role for awd in regulating cell differentiation and motility via regulation of growth factor receptor signaling. The latter function is mainly mediated by control of endocytosis. This review provides a historical account of the discovery and subsequent analyses of the awd gene. We will also discuss the possible molecular function of the Awd protein that underlies the endocytic function.
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Affiliation(s)
- Gouthami Nallamothu
- Department of Pathology and Laboratory Medicine, and Hollings Cancer Center, Medical University of South Carolina, 86 Jonathan Lucas St., Charleston, SC 29425, USA
| | - Vincent Dammai
- Department of Pathology and Laboratory Medicine, and Hollings Cancer Center, Medical University of South Carolina, 86 Jonathan Lucas St., Charleston, SC 29425, USA
| | - Tien Hsu
- Department of Pathology and Laboratory Medicine, and Hollings Cancer Center, Medical University of South Carolina, 86 Jonathan Lucas St., Charleston, SC 29425, USA
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Abstract
The growth suppressive function of the retinoblastoma (pRB) tumor suppressor family is largely attributed to its ability to negatively regulate the family of E2F transcriptional factors and, as a result, to repress E2F-dependent transcription. Deregulation of the pRB pathway is thought to be an obligatory event in most types of cancers. The large number of mammalian E2F proteins is one of the major obstacles that complicate their genetic analysis. In Drosophila, the E2F family consists of only two members. They are classified as an activator (dE2F1) and a repressor (dE2F2). It has been previously shown that proliferation of de2f1 mutant cells is severely reduced due to unchecked activity of the repressor dE2F2 in these cells. We report here a mosaic screen utilizing the de2f1 mutant phenotype to identify suppressors that overcome the dE2F2/RBF-dependent proliferation block. We have isolated l(3)mbt and B52, which are known to be required for dE2F2 function, as well as genes that were not previously linked to the E2F/pRB pathway such as Doa, gfzf, and CG31133. Inactivation of gfzf, Doa, or CG31133 does not relieve repression by dE2F2. We have shown that gfzf and CG31133 potentiate E2F-dependent activation and synergize with inactivation of RBF, suggesting that they may act in parallel to dE2F. Thus, our results demonstrate the efficacy of the described screening strategy for studying regulation of the dE2F/RBF pathway in vivo.
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Mehta A. The cystic fibrosis transmembrane recruiter the alter ego of CFTR as a multi-kinase anchor. Pflugers Arch 2007; 455:215-21. [PMID: 17805562 PMCID: PMC2629509 DOI: 10.1007/s00424-007-0290-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2006] [Revised: 04/27/2007] [Accepted: 05/11/2007] [Indexed: 11/03/2022]
Abstract
This review focuses on a newly discovered interaction between protein kinases involved in cellular energetics, a process that may be disturbed in cystic fibrosis for unknown reasons. I propose a new model where kinase-mediated cellular transmission of energy provides mechanistic insight to a latent role of the cystic fibrosis transmembrane conductance regulator (CFTR). I suggest that CFTR acts as a multi-kinase recruiter to the apical epithelial membrane. My group finds that, in the cytosol, two protein kinases involved in cell energy homeostasis, nucleoside diphosphate kinase (NDPK) and AMP-activated kinase (AMPK), bind one another. Preliminary data suggest that both can also bind CFTR (function unclear). The disrupted role of this CFTR-kinase complex as ‘membrane transmitter to the cell’ is proposed as an alternative paradigm to the conventional ion transport mediated and CFTR/chloride-centric view of cystic fibrosis pathogenesis. Chloride remains important, but instead, chloride-induced control of the phosphohistidine content of one kinase component (NDPK, via a multi-kinase complex that also includes a third kinase, CK2; formerly casein kinase 2). I suggest that this complex provides the necessary near-equilibrium conditions needed for efficient transmission of phosphate energy to proteins controlling cellular energetics. Crucially, a new role for CFTR as a kinase controller is proposed with ionic concentration acting as a signal. The model posits a regulatory control relay for energy sensing involving a cascade of protein kinases bound to CFTR.
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Affiliation(s)
- Anil Mehta
- Department of Maternal and Child Health Sciences, University of Dundee, Ninewells Hospital, Dundee DD1 9SY, UK.
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Provost E, Shearn A. The Suppressor of Killer of prune, a unique glutathione S-transferase. J Bioenerg Biomembr 2007; 38:189-95. [PMID: 16944302 DOI: 10.1007/s10863-006-9034-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The prune-Killer of prune conditional dominant, lethal interaction in Drosophila was identified in the 1950s, but its mechanism remains unknown. We undertook a genetic screen for suppressors of this lethal interaction and identified a gene we named, Suppressor of Killer of prune Su(Kpn). Su(Kpn) is a unique protein with four N-terminal FLYWCH zinc-finger domains, an acidic domain and a C-terminal glutathione S-transferase (GST) domain. The GST domain of Su(Kpn) is of particular interest because GSTs are usually independent of other protein domains. While GSTs are generally thought of as detoxifying enzymes, they are also associated with cellular toxicity. We predict that the GST domain of the Su(Kpn) creates a toxic product in prune-Killer of prune flies that is lethal. The substrate of the Su(Kpn) remains unknown.
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Affiliation(s)
- Elayne Provost
- Department of Biology, Johns Hopkins University, 3400 North Charles St, Baltimore, MD 21210, USA
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