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Russell JJ, Theriot JA, Sood P, Marshall WF, Landweber LF, Fritz-Laylin L, Polka JK, Oliferenko S, Gerbich T, Gladfelter A, Umen J, Bezanilla M, Lancaster MA, He S, Gibson MC, Goldstein B, Tanaka EM, Hu CK, Brunet A. Non-model model organisms. BMC Biol 2017; 15:55. [PMID: 28662661 PMCID: PMC5492503 DOI: 10.1186/s12915-017-0391-5] [Citation(s) in RCA: 119] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Model organisms are widely used in research as accessible and convenient systems to study a particular area or question in biology. Traditionally only a handful of organisms have been widely studied, but modern research tools are enabling researchers to extend the set of model organisms to include less-studied and more unusual systems. This Forum highlights a range of 'non-model model organisms' as emerging systems for tackling questions across the whole spectrum of biology (and beyond), the opportunities and challenges, and the outlook for the future.
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Affiliation(s)
- James J Russell
- Department of Biology, Howard Hughes Medical Institute Stanford University, Stanford, CA, 94305, USA
| | - Julie A Theriot
- Departments of Biochemistry and of Microbiology & Immunology, Howard Hughes Medical Institute Stanford University, Stanford, CA, 94305, USA.
| | - Pranidhi Sood
- Department of Biochemistry & Biophysics, University of California San Francisco, 600 16th St, San Francisco, CA, 94158, USA
| | - Wallace F Marshall
- Department of Biochemistry & Biophysics, University of California San Francisco, 600 16th St, San Francisco, CA, 94158, USA.
| | - Laura F Landweber
- Departments of Biochemistry & Molecular Biophysics and Biological Sciences, Columbia University, New York, NY, 10032, USA
| | | | - Jessica K Polka
- Visiting Scholar, Whitehead Institute, 9 Cambridge Center, Cambridge, MA, 02142, USA
| | - Snezhana Oliferenko
- The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
- Randall Division of Cell and Molecular Biophysics, New Hunt's House, Guy's Campus, King's College London, London, SE1 1UL, UK
| | - Therese Gerbich
- 516 Fordham Hall, University of North Carolina Chapel Hill, Chapel Hill, NC, 27514, USA
| | - Amy Gladfelter
- 516 Fordham Hall, University of North Carolina Chapel Hill, Chapel Hill, NC, 27514, USA
| | - James Umen
- Donald Danforth Plant Science Center, 975 N. Warson Rd, St. Louis, MO, 63132, USA
| | | | - Madeline A Lancaster
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Francis Crick Avenue, CB2 0QH, Cambridge, UK
| | - Shuonan He
- Stowers Institute for Medical Research, Kansas City, MO, 64110, USA
| | - Matthew C Gibson
- Stowers Institute for Medical Research, Kansas City, MO, 64110, USA
- Department of Anatomy and Cell Biology, The University of Kansas School of Medicine, Kansas City, KS, 66160, USA
| | - Bob Goldstein
- Biology Department, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Elly M Tanaka
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Campus Vienna Biocenter 1, 1030, Vienna, Austria
| | - Chi-Kuo Hu
- Department of Genetics, Stanford University, Stanford, CA, 94305, USA
| | - Anne Brunet
- Department of Genetics, Stanford University, Stanford, CA, 94305, USA
- Glenn Laboratories for the Biology of Aging at Stanford, Stanford, CA, 94305, USA
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Fritz-Laylin LK, Lord SJ, Mullins RD. WASP and SCAR are evolutionarily conserved in actin-filled pseudopod-based motility. J Cell Biol 2017; 216:1673-1688. [PMID: 28473602 PMCID: PMC5461030 DOI: 10.1083/jcb.201701074] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Revised: 03/12/2017] [Accepted: 03/31/2017] [Indexed: 01/08/2023] Open
Abstract
Eukaryotic cells use diverse cellular mechanisms to crawl through complex environments. Fritz-Laylin et al. define α-motility as a mode of migration associated with dynamic, actin-filled pseudopods and show that WASP and SCAR constitute an evolutionarily conserved genetic signature of α-motility. Diverse eukaryotic cells crawl through complex environments using distinct modes of migration. To understand the underlying mechanisms and their evolutionary relationships, we must define each mode and identify its phenotypic and molecular markers. In this study, we focus on a widely dispersed migration mode characterized by dynamic actin-filled pseudopods that we call “α-motility.” Mining genomic data reveals a clear trend: only organisms with both WASP and SCAR/WAVE—activators of branched actin assembly—make actin-filled pseudopods. Although SCAR has been shown to drive pseudopod formation, WASP’s role in this process is controversial. We hypothesize that these genes collectively represent a genetic signature of α-motility because both are used for pseudopod formation. WASP depletion from human neutrophils confirms that both proteins are involved in explosive actin polymerization, pseudopod formation, and cell migration. WASP and WAVE also colocalize to dynamic signaling structures. Moreover, retention of WASP together with SCAR correctly predicts α-motility in disease-causing chytrid fungi, which we show crawl at >30 µm/min with actin-filled pseudopods. By focusing on one migration mode in many eukaryotes, we identify a genetic marker of pseudopod formation, the morphological feature of α-motility, providing evidence for a widely distributed mode of cell crawling with a single evolutionary origin.
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Affiliation(s)
- Lillian K Fritz-Laylin
- Department of Cellular and Molecular Pharmacology, Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 94143
| | - Samuel J Lord
- Department of Cellular and Molecular Pharmacology, Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 94143
| | - R Dyche Mullins
- Department of Cellular and Molecular Pharmacology, Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 94143
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Ellis RE, Stanfield GM. The regulation of spermatogenesis and sperm function in nematodes. Semin Cell Dev Biol 2014; 29:17-30. [PMID: 24718317 PMCID: PMC4082717 DOI: 10.1016/j.semcdb.2014.04.005] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Accepted: 04/01/2014] [Indexed: 12/12/2022]
Abstract
In the nematode C. elegans, both males and self-fertile hermaphrodites produce sperm. As a result, researchers have been able to use a broad range of genetic and genomic techniques to dissect all aspects of sperm development and function. Their results show that the early stages of spermatogenesis are controlled by transcriptional and translational processes, but later stages are dominated by protein kinases and phosphatases. Once spermatids are produced, they participate in many interactions with other cells - signals from the somatic gonad determine when sperm activate and begin to crawl, signals from the female reproductive tissues guide the sperm, and signals from sperm stimulate oocytes to mature and be ovulated. The sperm also show strong competitive interactions with other sperm and oocytes. Some of the molecules that mediate these processes have conserved functions in animal sperm, others are conserved proteins that have been adapted for new roles in nematode sperm, and some are novel proteins that provide insights into evolutionary change. The advent of new techniques should keep this system on the cutting edge of research in cellular and reproductive biology.
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Affiliation(s)
- Ronald E Ellis
- Department of Molecular Biology, Rowan University SOM, B303 Science Center, 2 Medical Center Drive, Stratford, NJ 08084, United States.
| | - Gillian M Stanfield
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, United States
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Role of posttranslational modifications in C. elegans and ascaris spermatogenesis and sperm function. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 759:215-39. [PMID: 25030766 DOI: 10.1007/978-1-4939-0817-2_10] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Generally, spermatogenesis and sperm function involve widespread posttranslational modification of regulatory proteins in many different species. Nematode spermatogenesis has been studied in detail, mostly by genetic/molecular genetic techniques in the free-living Caenorhabditis elegans and by biochemistry/cell biology in the pig parasite Ascaris suum. Like other nematodes, both of these species produce sperm that use a form of amoeboid motility termed crawling, and many aspects of spermatogenesis are likely to be similar in both species. Consequently, work in these two nematode species has been largely complementary. Work in C. elegans has identified a number of spermatogenesis-defective genes and, so far, 12 encode enzymes that are implicated as catalysts of posttranslational protein modification. Crawling motility involves extension of a single pseudopod and this process is powered by a unique cytoskeleton composed of Major Sperm Protein (MSP) and accessory proteins, instead of the more widely observed actin. In Ascaris, pseudopod extension and crawling motility can be reconstituted in vitro, and biochemical studies have begun to reveal how posttranslational protein modifications, including phosphorylation, dephosphorylation and proteolysis, participate in these processes.
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Fraire-Zamora JJ, Cardullo RA. The physiological acquisition of amoeboid motility in nematode sperm: is the tail the only thing the sperm lost? Mol Reprod Dev 2010; 77:739-50. [PMID: 20803732 DOI: 10.1002/mrd.21193] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Nematode spermatozoa are highly specialized amoeboid cells that must acquire motility through the extension of a single pseudopod. Despite morphological and molecular differences with flagellated spermatozoa (including a non-actin-based cytoskeleton), nematode sperm must also respond to cues present in the female reproductive tract that render them motile, thereby allowing them to locate and fertilize the egg. The factors that trigger pseudopod extension in vivo are unknown, although current models suggest the activation through proteases acting on the sperm surface resulting in a myriad of biochemical, physiological, and morphological changes. Compelling evidence shows that pseudopod extension is under the regulation of physiological events also observed in other eukaryotic cells (including flagellated sperm) that involve membrane rearrangements in response to extracellular cues that initiate various signal transduction pathways. An integrative approach to the study of nonflagellated spermatozoa will shed light on the identification of unique and conserved processes during fertilization among different taxa.
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Affiliation(s)
- Juan J Fraire-Zamora
- Department of Biology and the Graduate Program in Evolution, Ecology, and Organismal Biology, University of California, Riverside, California 92521, USA
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del Castillo-Olivares A, Smith HE. Critical contact residues that mediate polymerization of nematode major sperm protein. J Cell Biochem 2008; 104:477-87. [PMID: 18022815 DOI: 10.1002/jcb.21636] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The polymerization of protein filaments provides the motive force in a variety of cellular processes involving cell motility and intracellular transport. Regulated assembly and disassembly of the major sperm protein (MSP) underlies amoeboid movement in nematode sperm, and offers an attractive model system for characterizing the biomechanical properties of filament formation and force generation. To that end, structure-function studies of MSP from the nematode Caenorhabditis elegans have been performed. Recombinant MSP was purified from Escherichia coli using a novel affinity chromatography technique, and filament assembly was assessed by in vitro polymerization in the presence of polyethylene glycol. Prior molecular studies and structure from X-ray crystallography have implicated specific residues in protein-protein interactions necessary for filament assembly. Purified MSP containing substitutions in these residues fails to form filaments in vitro. Short peptides based on predicted sites of interaction also effectively disrupt MSP polymerization. These results confirm the structural determination of intermolecular contacts and demonstrate the importance of these residues in MSP assembly.
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Affiliation(s)
- Antonio del Castillo-Olivares
- Center for Advanced Research in Biotechnology, University of Maryland Biotechnology Institute, Rockville, Maryland 20850, USA
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Miao L, Yi K, Mackey JM, Roberts TM. Reconstitution in vitro of MSP-based filopodium extension in nematode sperm. ACTA ACUST UNITED AC 2007; 64:235-47. [PMID: 17183548 DOI: 10.1002/cm.20177] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The major sperm protein (MSP) motility system in nematode sperm is best known for propelling the movement of mature sperm, where it has taken over the role usually played by actin in amoeboid cell motility. However, MSP filaments also drive the extension of filopodia, transient organelles composed of a core bundle of MSP filaments, that form in the late in sperm development but are not found on crawling cells. We have reconstituted filopodial extension in vitro whereby thin bundles of MSP filaments, each enveloped by a membrane sheath at their growing end, elongated at rates up to 17 microm/min. These bundles often exceeded 500 microm in length but were comprised of filaments only 1 microm long. The reconstituted filopodia assembled in the same cell-free sperm extracts that produced MSP fibers, robust meshworks of filaments that exhibit the same organization and dynamics as the lamellipodial filament system that propels sperm movement. The filopodia and fibers that assembled in vitro both had a membranous structure at their growing end, shared four MSP accessory proteins, and responded identically to agents that alter MSP-based motility by modulating protein phosphorylation. However, filopodia grew three- to four-fold faster than fibers. The reconstitution of filopodial extension shows that, like the actin cytoskeleton, MSP filaments can adopt two architectures, bundles and meshworks, each capable of pushing against membranes to generate protrusion. The reconstitution of both forms of motility in the same in vitro system provides a promising avenue for understanding how the forces for membrane protrusion are produced.
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Affiliation(s)
- Long Miao
- Department of Biological Science, Florida State University, Tallahassee, Florida 32306, USA
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