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Nishio S, Emori C, Wiseman B, Fahrenkamp D, Dioguardi E, Zamora-Caballero S, Bokhove M, Han L, Stsiapanava A, Algarra B, Lu Y, Kodani M, Bainbridge RE, Komondor KM, Carlson AE, Landreh M, de Sanctis D, Yasumasu S, Ikawa M, Jovine L. ZP2 cleavage blocks polyspermy by modulating the architecture of the egg coat. Cell 2024; 187:1440-1459.e24. [PMID: 38490181 DOI: 10.1016/j.cell.2024.02.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 11/07/2023] [Accepted: 02/09/2024] [Indexed: 03/17/2024]
Abstract
Following the fertilization of an egg by a single sperm, the egg coat or zona pellucida (ZP) hardens and polyspermy is irreversibly blocked. These events are associated with the cleavage of the N-terminal region (NTR) of glycoprotein ZP2, a major subunit of ZP filaments. ZP2 processing is thought to inactivate sperm binding to the ZP, but its molecular consequences and connection with ZP hardening are unknown. Biochemical and structural studies show that cleavage of ZP2 triggers its oligomerization. Moreover, the structure of a native vertebrate egg coat filament, combined with AlphaFold predictions of human ZP polymers, reveals that two protofilaments consisting of type I (ZP3) and type II (ZP1/ZP2/ZP4) components interlock into a left-handed double helix from which the NTRs of type II subunits protrude. Together, these data suggest that oligomerization of cleaved ZP2 NTRs extensively cross-links ZP filaments, rigidifying the egg coat and making it physically impenetrable to sperm.
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Affiliation(s)
- Shunsuke Nishio
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | - Chihiro Emori
- Department of Experimental Genome Research, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan; Immunology Frontier Research Center, Osaka University, Suita, Osaka, Japan
| | - Benjamin Wiseman
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | - Dirk Fahrenkamp
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | - Elisa Dioguardi
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | | | - Marcel Bokhove
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | - Ling Han
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | - Alena Stsiapanava
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | - Blanca Algarra
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | - Yonggang Lu
- Department of Experimental Genome Research, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan; Immunology Frontier Research Center, Osaka University, Suita, Osaka, Japan
| | - Mayo Kodani
- Department of Experimental Genome Research, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan; Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka, Japan
| | - Rachel E Bainbridge
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, USA
| | - Kayla M Komondor
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, USA
| | - Anne E Carlson
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, USA
| | - Michael Landreh
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden; Department of Cell and Molecular Biology, Uppsala University, 75124 Uppsala, Sweden
| | | | - Shigeki Yasumasu
- Department of Materials and Life Sciences, Faculty of Science and Technology, Sophia University, Tokyo, Japan
| | - Masahito Ikawa
- Department of Experimental Genome Research, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan; Immunology Frontier Research Center, Osaka University, Suita, Osaka, Japan; Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka, Japan; Center for Infectious Disease Education and Research (CiDER), Osaka University, Suita, Osaka, Japan
| | - Luca Jovine
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden.
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Morita M, Kitanobo S, Ohki S, Shiba K, Inaba K. Positive selection on ADAM10 builds species recognition in the synchronous spawning coral Acropora. Front Cell Dev Biol 2023; 11:1171495. [PMID: 37152284 PMCID: PMC10157049 DOI: 10.3389/fcell.2023.1171495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 04/10/2023] [Indexed: 05/09/2023] Open
Abstract
The reef-building coral Acropora is a broadcast spawning hermaphrodite including more than 110 species in the Indo-Pacific. In addition, many sympatric species show synchronous spawning. The released gametes need to mate with conspecifics in the mixture of the gametes of many species for their species boundaries. However, the mechanism underlying the species recognition of conspecifics at fertilization remains unknown. We hypothesized that rapid molecular evolution (positive selection) in genes encoding gamete-composing proteins generates polymorphic regions that recognize conspecifics in the mixture of gametes from many species. We identified gamete proteins of Acropora digitifera using mass spectrometry and screened the genes that support branch site models that set the "foreground" branches showing strict fertilization specificity. ADAM10, ADAM17, Integrin α9, and Tetraspanin4 supported branch-site model and had positively selected site(s) that produced polymorphic regions. Therefore, we prepared antibodies against the proteins of A. digitifera that contained positively selected site(s) to analyze their functions in fertilization. The ADAM10 antibody reacted only with egg proteins of A. digitifera, and immunohistochemistry showed ADAM10 localized around the egg surface. Moreover, the ADAM10 antibody inhibited only A. digitifera fertilization but not the relative synchronous spawning species A. papillare. This study indicates that ADAM10 has evolved to gain fertilization specificity during speciation and contributes to species boundaries in this multi-species, synchronous-spawning, and species-rich genus.
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Affiliation(s)
- Masaya Morita
- Sesoko Station, Tropical Biosphere Research Center, University of the Ryukyus, Nishihara, Japan
- *Correspondence: Masaya Morita,
| | - Seiya Kitanobo
- Sesoko Station, Tropical Biosphere Research Center, University of the Ryukyus, Nishihara, Japan
- Shimoda Marine Research Center, University of Tsukuba, Shimoda, Japan
| | - Shun Ohki
- Department of Immunology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Kogiku Shiba
- Shimoda Marine Research Center, University of Tsukuba, Shimoda, Japan
| | - Kazuo Inaba
- Shimoda Marine Research Center, University of Tsukuba, Shimoda, Japan
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Roberts EK, Tardif S, Wright EA, Platt RN, Bradley RD, Hardy DM. Rapid divergence of a gamete recognition gene promoted macroevolution of Eutheria. Genome Biol 2022; 23:155. [PMID: 35821049 PMCID: PMC9275260 DOI: 10.1186/s13059-022-02721-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 06/29/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Speciation genes contribute disproportionately to species divergence, but few examples exist, especially in vertebrates. Here we test whether Zan, which encodes the sperm acrosomal protein zonadhesin that mediates species-specific adhesion to the egg's zona pellucida, is a speciation gene in placental mammals. RESULTS Genomic ontogeny reveals that Zan arose by repurposing of a stem vertebrate gene that was lost in multiple lineages but retained in Eutheria on acquiring a function in egg recognition. A 112-species Zan sequence phylogeny, representing 17 of 19 placental Orders, resolves all species into monophyletic groups corresponding to recognized Orders and Suborders, with <5% unsupported nodes. Three other rapidly evolving germ cell genes (Adam2, Zp2, and Prm1), a paralogous somatic cell gene (TectA), and a mitochondrial gene commonly used for phylogenetic analyses (Cytb) all yield trees with poorer resolution than the Zan tree and inferior topologies relative to a widely accepted mammalian supertree. Zan divergence by intense positive selection produces dramatic species differences in the protein's properties, with ordinal divergence rates generally reflecting species richness of placental Orders consistent with expectations for a speciation gene that acts across a wide range of taxa. Furthermore, Zan's combined phylogenetic utility and divergence exceeds those of all other genes known to have evolved in Eutheria by positive selection, including the only other mammalian speciation gene, Prdm9. CONCLUSIONS Species-specific egg recognition conferred by Zan's functional divergence served as a mode of prezygotic reproductive isolation that promoted the extraordinary adaptive radiation and success of Eutheria.
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Affiliation(s)
- Emma K Roberts
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, USA.,Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Steve Tardif
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX, USA.,Reproductive Biology Division, JangoBio, Fitchburg, WI, USA
| | - Emily A Wright
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, USA
| | - Roy N Platt
- Host-Pathogen Interaction Program, Texas Biomedical Research Institute, San Antonio, TX, USA
| | - Robert D Bradley
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, USA.,Natural Science Research Laboratory, Museum of Texas Tech University, Lubbock, TX, USA
| | - Daniel M Hardy
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX, USA.
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Carlisle JA, Glenski MA, Swanson WJ. Recurrent Duplication and Diversification of Acrosomal Fertilization Proteins in Abalone. Front Cell Dev Biol 2022; 10:795273. [PMID: 35465314 PMCID: PMC9022041 DOI: 10.3389/fcell.2022.795273] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 02/21/2022] [Indexed: 12/04/2022] Open
Abstract
Reproductive proteins mediating fertilization commonly exhibit rapid sequence diversification driven by positive selection. This pattern has been observed among nearly all taxonomic groups, including mammals, invertebrates, and plants, and is remarkable given the essential nature of the molecular interactions mediating fertilization. Gene duplication is another important mechanism that facilitates the generation of molecular novelty through functional divergence. Following duplication, paralogs may partition ancestral gene function (subfunctionalization) or acquire new roles (neofunctionalization). However, the contributions of duplication followed by sequence diversification to the molecular diversity of gamete recognition genes has been understudied in many models of fertilization. The marine gastropod mollusk abalone is a classic model for fertilization. Its two acrosomal proteins (lysin and sp18) are ancient gene duplicates with unique gamete recognition functions. Through detailed genomic and bioinformatic analyses we show how duplication events followed by sequence diversification has played an ongoing role in the evolution of abalone acrosomal proteins. The common ancestor of abalone had four members of its acrosomal protein family in a tandem gene array that repeatedly experienced positive selection. We find that both sp18 paralogs contain positively selected sites located in different regions of the paralogs, suggestive of functional divergence where selection acted upon distinct binding interfaces in each paralog. Further, a more recent species-specific duplication of both lysin and sp18 in the European abalone H. tuberculata is described. Despite clade-specific acrosomal protein paralogs, there are no concomitant duplications of egg coat proteins in H. tuberculata, indicating that duplication of egg proteins per se is not responsible for retention of duplicated acrosomal proteins. We hypothesize that, in a manner analogous to host/pathogen evolution, sperm proteins are selected for increased diversity through extensive sequence divergence and recurrent duplication driven by conflict mechanisms.
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Affiliation(s)
- J. A. Carlisle
- Genome Sciences Department, University of Washington Medical School, Seattle, WA, United States
- *Correspondence: J. A. Carlisle,
| | - M. A. Glenski
- Department of Biology, Gonzaga University, Spokane, WA, United States
| | - W. J. Swanson
- Genome Sciences Department, University of Washington Medical School, Seattle, WA, United States
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Rivera AM, Swanson WJ. The Importance of Gene Duplication and Domain Repeat Expansion for the Function and Evolution of Fertilization Proteins. Front Cell Dev Biol 2022; 10:827454. [PMID: 35155436 PMCID: PMC8830517 DOI: 10.3389/fcell.2022.827454] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Accepted: 01/12/2022] [Indexed: 11/13/2022] Open
Abstract
The process of gene duplication followed by gene loss or evolution of new functions has been studied extensively, yet the role gene duplication plays in the function and evolution of fertilization proteins is underappreciated. Gene duplication is observed in many fertilization protein families including Izumo, DCST, ZP, and the TFP superfamily. Molecules mediating fertilization are part of larger gene families expressed in a variety of tissues, but gene duplication followed by structural modifications has often facilitated their cooption into a fertilization function. Repeat expansions of functional domains within a gene also provide opportunities for the evolution of novel fertilization protein. ZP proteins with domain repeat expansions are linked to species-specificity in fertilization and TFP proteins that experienced domain duplications were coopted into a novel sperm function. This review outlines the importance of gene duplications and repeat domain expansions in the evolution of fertilization proteins.
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Zhong M, Wu H, Li F, Shan X, Ji C. Proteomic analysis revealed gender-specific responses of mussels (Mytilus galloprovincialis) to trichloropropyl phosphate (TCPP) exposure. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 267:115537. [PMID: 32892020 DOI: 10.1016/j.envpol.2020.115537] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 08/11/2020] [Accepted: 08/25/2020] [Indexed: 06/11/2023]
Abstract
Trichloropropyl phosphate (TCPP) is a halogenated organophosphate ester that is widely used as flame retardants and plasticizers. In this study, gender-specific accumulation and responses in mussel Mytilus galloprovincialis to TCPP exposure were focused and highlighted. After TCPP (100 nmol L-1) exposure for 42 days, male mussels showed similar average bioaccumulation (37.14 ± 6.09 nmol g-1 fat weight (fw)) of TCPP with that in female mussels (32.28 ± 4.49 nmol g-1 fw). Proteomic analysis identified 219 differentially expressed proteins (DEPs) between male and female mussels in control group. There were 52 and 54 DEPs induced by TCPP in male and female mussels, respectively. Interestingly, gender-specific DEPs included 37 and 41 DEPs induced by TCPP in male and female mussels, respectively. The proteomic differences between male and female mussels were related to protein synthesis and degradation, energy metabolism, and functions of cytoskeleton and motor proteins. TCPP influenced protein synthesis, energy metabolism, cytoskeleton functions, immunity, and reproduction in both male and female mussels. Protein-protein interaction (PPI) networks indicated that protein synthesis and energy metabolism were the main biological processes influenced by TCPP. However, DEPs involved in these processes and their interaction patterns were quite different between male and female mussels. Basically, twelve ribosome DEPs which directly or indirectly interacted were found in protein synthesis in TCPP-exposed male mussels, while only 3 ribosome DEPs (not interacted) in TCPP-exposed female mussels. In energy metabolism, only 4 DEPs (with the relatively simple interaction pattern) mainly resided in fatty acid metabolism, butanoate/propanoate metabolism and glucose metabolism were discovered in TCPP-exposed male mussels, and more DEPs (with multiple interactions) functioned in TCA cycle and pyruvate/glyoxylate/dicarboxylate metabolism were found in TCCP-exposed female mussels. Taken together, TCPP induced gender-specific toxicological effects in mussels, which may shed new lights on further understanding the toxicological mechanisms of TCPP in aquatic organisms.
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Affiliation(s)
- Mingyu Zhong
- CAS Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research (YIC), Chinese Academy of Sciences (CAS), Shandong Key Laboratory of Coastal Environmental Processes, YICCAS, Yantai, 264003, PR China
| | - Huifeng Wu
- CAS Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research (YIC), Chinese Academy of Sciences (CAS), Shandong Key Laboratory of Coastal Environmental Processes, YICCAS, Yantai, 264003, PR China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, PR China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, 266071, PR China.
| | - Fei Li
- CAS Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research (YIC), Chinese Academy of Sciences (CAS), Shandong Key Laboratory of Coastal Environmental Processes, YICCAS, Yantai, 264003, PR China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, 266071, PR China
| | - Xiujuan Shan
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, PR China
| | - Chenglong Ji
- CAS Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research (YIC), Chinese Academy of Sciences (CAS), Shandong Key Laboratory of Coastal Environmental Processes, YICCAS, Yantai, 264003, PR China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, PR China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, 266071, PR China
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7
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Carlisle JA, Swanson WJ. Molecular mechanisms and evolution of fertilization proteins. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2020; 336:652-665. [PMID: 33015976 DOI: 10.1002/jez.b.23004] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 09/04/2020] [Accepted: 09/08/2020] [Indexed: 12/11/2022]
Abstract
Sexual reproduction involves a cascade of molecular interactions between the sperm and the egg culminating in cell-cell fusion. Vital steps mediating fertilization include chemoattraction of the sperm to the egg, induction of the sperm acrosome reaction, dissolution of the egg coat, and sperm-egg plasma membrane binding and fusion. Despite decades of research, only a handful of interacting gamete recognition proteins (GRPs) have been identified across taxa mediating each of these steps, most notably in abalone, sea urchins, and mammals. This review outlines and compares notable GRP pairs mediating sperm-egg recognition in these three significant model systems and discusses the molecular basis of species-specific fertilization driven by GRP function. In addition, we explore the evolutionary theory behind the rapid diversification of GRPs between species. In particular, we focus on how the coevolution between interacting sperm and egg proteins may contribute to the formation of boundaries to hybridization. Finally, we discuss how pairing structural information with evolutionary insights can improve our understanding of mechanisms of fertilization and their origins.
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Affiliation(s)
- Jolie A Carlisle
- Department of Genome Sciences, University of Washington Medical School, Seattle, Washington, USA
| | - Willie J Swanson
- Department of Genome Sciences, University of Washington Medical School, Seattle, Washington, USA
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Lobov AA, Maltseva AL, Mikhailova NA, Granovitch AI. The Molecular Mechanisms of Gametic Incompatibility in Invertebrates. Acta Naturae 2019; 11:4-15. [PMID: 31720011 PMCID: PMC6826153 DOI: 10.32607/20758251-2019-11-3-4-15] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Accepted: 09/09/2019] [Indexed: 12/02/2022] Open
Abstract
Fertilization (gamete fusion followed by zygote formation) is a multistage process. Each stage is mediated by ligand-receptor recognition of gamete interaction molecules. This recognition includes the movement of sperm in the gradient of egg chemoattractants, destruction of the egg envelope by acrosomal proteins, etc. Gametic incompatibility is one of the mechanisms of reproductive isolation. It is based on species-specific molecular interactions that prevent heterospecific fertilization. Although gametic incompatibility may occur in any sexually reproducing organism, it has been studied only in a few model species. Gamete interactions in different taxa involve generally similar processes, but they often employ non-homologous molecules. Gamete recognition proteins evolve rapidly, like immunity proteins, and include many taxon-specific families. In fact, recently appeared proteins particularly contribute to reproductive isolation via gametic incompatibility. Thus, we can assume a multiple, independent origin of this type of reproductive isolation throughout animal evolution. Gametic incompatibility can be achieved at any fertilization stage and entails different consequences at different taxonomic levels and ranges, from complete incompatibility between closely related species to partial incompatibility between distantly related taxa.
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Affiliation(s)
- A. A. Lobov
- Department of Invertebrate Zoology, Faculty of Biology, St Petersburg State University, Universitetskaya Emb. 7/9, St. Petersburg, 199034, Russia
- Laboratory of Regenerative Biomedicine, Institute of Cytology of the Russian Academy of Sciences, Tikhoretsky Ave. 4, St. Petersburg, 194064, Russia
| | - A. L. Maltseva
- Department of Invertebrate Zoology, Faculty of Biology, St Petersburg State University, Universitetskaya Emb. 7/9, St. Petersburg, 199034, Russia
| | - N. A. Mikhailova
- Centre of Cell Technologies, Institute of Cytology of the Russian Academy of Sciences, Tikhoretsky Ave. 4, St. Petersburg, 194064, Russia
| | - A. I. Granovitch
- Department of Invertebrate Zoology, Faculty of Biology, St Petersburg State University, Universitetskaya Emb. 7/9, St. Petersburg, 199034, Russia
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Morita M, Ugwu SI, Kohda M. Variations in the breeding behavior of cichlids and the evolution of the multi-functional seminal plasma protein, seminal plasma glycoprotein 120. BMC Evol Biol 2018; 18:197. [PMID: 30572831 PMCID: PMC6302530 DOI: 10.1186/s12862-018-1292-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Accepted: 11/09/2018] [Indexed: 11/27/2022] Open
Abstract
Background Seminal plasma proteins are associated with successful fertilization. However, their evolutionary correlation with fertilization mechanisms remains unclear. Cichlids from Lake Tanganyika show a variety-rich spawning behavior that is associated with the transfer of the sperm to the egg for fertilization. One of these behaviors, called “oral fertilization,” emerged during their speciation. In oral fertilization, females nuzzle the milt from male genitalia and pick up the released eggs in their mouths, which are then fertilized inside the oral cavity. Thus, the success of the fertilization is dependent on the retention of sperm in the oral cavity during spawning. Sperm aggregation and immobilization in viscous seminal plasma may help retain the sperm inside the oral cavity, which ultimately determines the success of the fertilization. Seminal plasma glycoprotein 120 (SPP120) is one of the major seminal plasma proteins present in cichlids. SPP120 has been implicated to immobilize sperm and increase the milt viscosity. However, the functional linkage between oral fertilization and seminal plasma proteins has not been investigated. Results During trials of simulated oral fertilization, it was observed that milt viscosity contributed to fertilization success by facilitating longer retention of the milt inside the mouth during spawning. Glycosylation of SPP120 was associated with high milt viscosity. Its glycosylation was specifically present in the milt of cichlid species exhibiting oral fertilization. Moreover, recombinant SPP120 from several the oral fertilization species strongly immobilized/aggregated sperm. Therefore, the functions of SPP120 (immobilization/aggregation and its glycosylation) may contribute to success of oral fertilization, and these functions of SPP120 are more prominent in oral fertilization species. In addition, comparative phylogenetic analyses showed a positive evolutionary correlation between SPP120 function and oral fertilization. Hence, these evolutions may have occurred to keep up with the transition in the mode of fertilization. In addition, rapid evolution in the molecular sequence might be associated with functional modifications of SPP120. Conclusion These results suggest that SPP120 might be associated with oral fertilization. In other words, reproductive traits that define the interaction between sperms and eggs could be the evolutionary selective force that cause the rapid functional modification of the fertilization-related reproductive protein, SPP120. Electronic supplementary material The online version of this article (10.1186/s12862-018-1292-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Masaya Morita
- Sesoko Station, Tropical Biosphere Research Center, University of the Ryukyus, Sesoko, Motobu, Okinawa, 905-0227, Japan.
| | - Stanley Ifeanyi Ugwu
- Sesoko Station, Tropical Biosphere Research Center, University of the Ryukyus, Sesoko, Motobu, Okinawa, 905-0227, Japan
| | - Masanori Kohda
- Laboratory of Animal Sociology, Department of Biology and Geosciences, Graduate School of Sciences, Osaka City University, Sumiyoshi, Osaka, 558-8585, Japan
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10
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Abstract
The egg coat, an extracellular matrix made up of glycoprotein filaments, plays a key role in animal fertilization by acting as a gatekeeper for sperm. Egg coat components polymerize using a common zona pellucida (ZP) "domain" module that consists of two related immunoglobulin-like domains, called ZP-N and ZP-C. The ZP module has also been recognized in a large number of other secreted proteins with different biological functions, whose mutations are linked to severe human diseases. During the last decade, tremendous progress has been made toward understanding the atomic architecture of the ZP module and the structural basis of its polymerization. Moreover, sperm-binding regions at the N-terminus of mollusk and mammalian egg coat subunits were found to consist of domain repeats that also adopt a ZP-N fold. This discovery revealed an unexpected link between invertebrate and vertebrate fertilization and led to the first structure of an egg coat-sperm protein recognition complex. In this review we summarize these exciting findings, discuss their functional implications, and outline future challenges that must be addressed in order to develop a comprehensive view of this family of biomedically important extracellular molecules.
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Affiliation(s)
- Marcel Bokhove
- Department of Biosciences and Nutrition & Center for Innovative Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Luca Jovine
- Department of Biosciences and Nutrition & Center for Innovative Medicine, Karolinska Institutet, Huddinge, Sweden.
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11
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Abstract
All animal oocytes are surrounded by a glycoproteinaceous egg coat, a specialized extracellular matrix that serves both structural and species-specific roles during fertilization. Egg coat glycoproteins polymerize into the extracellular matrix of the egg coat using a conserved protein-protein interaction module-the zona pellucida (ZP) domain-common to both vertebrates and invertebrates, suggesting that the basic structural features of egg coats have been conserved across hundreds of millions of years of evolution. Egg coat proteins, as with other proteins involved in reproduction, are frequently found to be rapidly evolving. Given that gamete compatibility must be maintained for the fitness of sexually reproducing organisms, this finding is somewhat paradoxical and suggests a role for adaptive diversification in reproductive protein evolution. Here we review the structure and function of metazoan egg coat proteins, with an emphasis on the potential role their evolution has played in the creation and maintenance of species boundaries.
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Affiliation(s)
- Emily E Killingbeck
- Department of Genome Sciences, University of Washington, Seattle, WA, United States.
| | - Willie J Swanson
- Department of Genome Sciences, University of Washington, Seattle, WA, United States.
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12
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Solution structure of sperm lysin yields novel insights into molecular dynamics of rapid protein evolution. Proc Natl Acad Sci U S A 2018; 115:1310-1315. [PMID: 29348201 DOI: 10.1073/pnas.1709061115] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Protein evolution is driven by the sum of different physiochemical and genetic processes that usually results in strong purifying selection to maintain biochemical functions. However, proteins that are part of systems under arms race dynamics often evolve at unparalleled rates that can produce atypical biochemical properties. In the marine mollusk abalone, lysin and vitelline envelope receptor for lysin (VERL) are a pair of rapidly coevolving proteins that are essential for species-specific interactions between sperm and egg. Despite extensive biochemical characterization of lysin-including crystal structures of multiple orthologs-it was unclear how sites under positive selection may facilitate recognition of VERL. Using a combination of targeted mutagenesis and multidimensional NMR, we present a high-definition solution structure of sperm lysin from red abalone (Haliotis rufescens). Unapparent from the crystallography data, multiple NMR-based analyses conducted in solution reveal clustering of the N and C termini to form a nexus of 13 positively selected sites that constitute a VERL binding interface. Evolutionary rate was found to be a significant predictor of backbone flexibility, which may be critical for lysin bioactivity and/or accelerated evolution. Flexible, rapidly evolving segments that constitute the VERL binding interface were also the most distorted regions of the crystal structure relative to what was observed in solution. While lysin has been the subject of extensive biochemical and evolutionary analyses for more than 30 years, this study highlights the enhanced insights gained from applying NMR approaches to rapidly evolving proteins.
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13
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Harper FM, Riley KJ, Rawson PD. Novel species-specific glycoprotein on the surface of Mytilus edulis and M. trossulus eggs. INVERTEBR REPROD DEV 2017. [DOI: 10.1080/07924259.2017.1361476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- F. M. Harper
- Department of Biology, Rollins College, Winter Park, FL, USA
- School of Marine Sciences, University of Maine, Orono, ME, USA
| | - K. J. Riley
- Department of Chemistry, Rollins College, Winter Park, FL, USA
| | - P. D. Rawson
- School of Marine Sciences, University of Maine, Orono, ME, USA
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14
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Hwang JY, Chung JJ. Sex at Atomic Resolution. Cell 2017. [PMID: 28622504 DOI: 10.1016/j.cell.2017.05.043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Interspecies fertilization is rare, partly due to species separation enforced at the molecular level. In this issue, Raj et al. now reveal the crystal structures of mollusk egg coat protein, VERL, complexed with cognate sperm protein lysin. Given that VERL is structurally similar to mammalian ZP2, the mechanism elucidating species-specific gamete recognition likely exists in mammals.
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Affiliation(s)
- Jae Yeon Hwang
- Department of Cellular & Molecular Physiology, Yale School of Medicine, New Haven, CT 06510, USA
| | - Jean-Ju Chung
- Department of Cellular & Molecular Physiology, Yale School of Medicine, New Haven, CT 06510, USA; Department of Obstetrics, Gynecology & Reproductive Sciences, Yale School of Medicine, New Haven, CT 06510, USA.
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15
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Raj I, Sadat Al Hosseini H, Dioguardi E, Nishimura K, Han L, Villa A, de Sanctis D, Jovine L. Structural Basis of Egg Coat-Sperm Recognition at Fertilization. Cell 2017. [PMID: 28622512 PMCID: PMC5480393 DOI: 10.1016/j.cell.2017.05.033] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Recognition between sperm and the egg surface marks the beginning of life in all sexually reproducing organisms. This fundamental biological event depends on the species-specific interaction between rapidly evolving counterpart molecules on the gametes. We report biochemical, crystallographic, and mutational studies of domain repeats 1–3 of invertebrate egg coat protein VERL and their interaction with cognate sperm protein lysin. VERL repeats fold like the functionally essential N-terminal repeat of mammalian sperm receptor ZP2, whose structure is also described here. Whereas sequence-divergent repeat 1 does not bind lysin, repeat 3 binds it non-species specifically via a high-affinity, largely hydrophobic interface. Due to its intermediate binding affinity, repeat 2 selectively interacts with lysin from the same species. Exposure of a highly positively charged surface of VERL-bound lysin suggests that complex formation both disrupts the organization of egg coat filaments and triggers their electrostatic repulsion, thereby opening a hole for sperm penetration and fusion. Sperm-binding repeats of mollusk VERL and mouse ZP2 egg coat proteins fold similarly Structures of VERL/lysin complexes reveal the atomic basis of egg coat-sperm recognition A medium-affinity VERL repeat selectively binds lysin from the same species VERL/lysin recognition suggests a mechanism for sperm penetration through the egg coat
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Affiliation(s)
- Isha Raj
- Department of Biosciences and Nutrition and Center for Innovative Medicine, Karolinska Institutet, Huddinge, SE-141 83, Sweden
| | - Hamed Sadat Al Hosseini
- Department of Biosciences and Nutrition and Center for Innovative Medicine, Karolinska Institutet, Huddinge, SE-141 83, Sweden
| | - Elisa Dioguardi
- Department of Biosciences and Nutrition and Center for Innovative Medicine, Karolinska Institutet, Huddinge, SE-141 83, Sweden
| | - Kaoru Nishimura
- Department of Biosciences and Nutrition and Center for Innovative Medicine, Karolinska Institutet, Huddinge, SE-141 83, Sweden
| | - Ling Han
- Department of Biosciences and Nutrition and Center for Innovative Medicine, Karolinska Institutet, Huddinge, SE-141 83, Sweden
| | - Alessandra Villa
- Department of Biosciences and Nutrition and Center for Innovative Medicine, Karolinska Institutet, Huddinge, SE-141 83, Sweden
| | - Daniele de Sanctis
- ESRF - The European Synchrotron Radiation Facility, Grenoble 38000, France
| | - Luca Jovine
- Department of Biosciences and Nutrition and Center for Innovative Medicine, Karolinska Institutet, Huddinge, SE-141 83, Sweden.
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16
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Shu L, Suter MJF, Räsänen K. Evolution of egg coats: linking molecular biology and ecology. Mol Ecol 2015; 24:4052-73. [DOI: 10.1111/mec.13283] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Revised: 06/12/2015] [Accepted: 06/17/2015] [Indexed: 12/18/2022]
Affiliation(s)
- Longfei Shu
- Department of Aquatic Ecology; Swiss Federal Institute of Aquatic Science and Technology; Eawag; 8600 Duebendorf Switzerland
- Institute of Integrative Biology; ETH Zurich; 8092 Zurich Switzerland
| | - Marc J.-F. Suter
- Department of Environmental Toxicology; Swiss Federal Institute of Aquatic Science and Technology; Eawag; 8600 Duebendorf Switzerland
- Department of Environmental Systems Science; Swiss Federal Institute of Technology; ETH Zurich; 8092 Zurich Switzerland
| | - Katja Räsänen
- Department of Aquatic Ecology; Swiss Federal Institute of Aquatic Science and Technology; Eawag; 8600 Duebendorf Switzerland
- Institute of Integrative Biology; ETH Zurich; 8092 Zurich Switzerland
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17
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Wilburn DB, Swanson WJ. From molecules to mating: Rapid evolution and biochemical studies of reproductive proteins. J Proteomics 2015; 135:12-25. [PMID: 26074353 DOI: 10.1016/j.jprot.2015.06.007] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 06/09/2015] [Accepted: 06/10/2015] [Indexed: 01/10/2023]
Abstract
UNLABELLED Sexual reproduction and the exchange of genetic information are essential biological processes for species across all branches of the tree of life. Over the last four decades, biochemists have continued to identify many of the factors that facilitate reproduction, but the molecular mechanisms that mediate this process continue to elude us. However, a recurring observation in this research has been the rapid evolution of reproductive proteins. In animals, the competing interests of males and females often result in arms race dynamics between pairs of interacting proteins. This phenomenon has been observed in all stages of reproduction, including pheromones, seminal fluid components, and gamete recognition proteins. In this article, we review how the integration of evolutionary theory with biochemical experiments can be used to study interacting reproductive proteins. Examples are included from both model and non-model organisms, and recent studies are highlighted for their use of state-of-the-art genomic and proteomic techniques. SIGNIFICANCE Despite decades of research, our understanding of the molecular mechanisms that mediate fertilization remain poorly characterized. To date, molecular evolutionary studies on both model and non-model organisms have provided some of the best inferences to elucidating the molecular underpinnings of animal reproduction. This review article details how biochemical and evolutionary experiments have jointly enhanced the field for 40 years, and how recent work using high-throughput genomic and proteomic techniques have shed additional insights into this crucial biological process.
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Affiliation(s)
- Damien B Wilburn
- Department of Genome Sciences, University of Washington, United States.
| | - Willie J Swanson
- Department of Genome Sciences, University of Washington, United States
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18
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Egge N, Muthusubramanian A, Cornwall GA. Amyloid properties of the mouse egg zona pellucida. PLoS One 2015; 10:e0129907. [PMID: 26043223 PMCID: PMC4456372 DOI: 10.1371/journal.pone.0129907] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Accepted: 05/14/2015] [Indexed: 01/15/2023] Open
Abstract
The zona pellucida (ZP) surrounding the oocyte is an extracellular fibrillar matrix that plays critical roles during fertilization including species-specific gamete recognition and protection from polyspermy. The mouse ZP is composed of three proteins, ZP1, ZP2, and ZP3, all of which have a ZP polymerization domain that directs protein fibril formation and assembly into the three-dimensional ZP matrix. Egg coats surrounding oocytes in nonmammalian vertebrates and in invertebrates are also fibrillar matrices and are composed of ZP domain-containing proteins suggesting the basic structure and function of the ZP/egg coat is highly conserved. However, sequence similarity between ZP domains is low across species and thus the mechanism for the conservation of ZP/egg coat structure and its function is not known. Using approaches classically used to identify amyloid including conformation-dependent antibodies and dyes, X-ray diffraction, and negative stain electron microscopy, our studies suggest the mouse ZP is a functional amyloid. Amyloids are cross-β sheet fibrillar structures that, while typically associated with neurodegenerative and prion diseases in mammals, can also carry out functional roles in normal cells without resulting pathology. An analysis of the ZP domain from mouse ZP3 and ZP3 homologs from five additional taxa using the algorithm AmylPred 2 to identify amyloidogenic sites, revealed in all taxa a remarkable conservation of regions that were predicted to form amyloid. This included a conserved amyloidogenic region that localized to a stretch of hydrophobic amino acids previously shown in mouse ZP3 to be essential for fibril assembly. Similarly, a domain in the yeast protein α-agglutinin/Sag 1p, that possesses ZP domain-like features and which is essential for mating, also had sites that were predicted to be amyloidogenic including a hydrophobic stretch that appeared analogous to the critical site in mouse ZP3. Together, these studies suggest that amyloidogenesis may be a conserved mechanism for ZP structure and function across billions of years of evolution.
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Affiliation(s)
- Nathan Egge
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, Texas, United States of America
| | - Archana Muthusubramanian
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, Texas, United States of America
| | - Gail A. Cornwall
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, Texas, United States of America
- * E-mail:
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19
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Kosman ET, Levitan DR. Sperm competition and the evolution of gametic compatibility in externally fertilizing taxa. Mol Hum Reprod 2014; 20:1190-7. [PMID: 25323969 DOI: 10.1093/molehr/gau069] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Proteins expressed on the surface of sperm and egg mediate gametic compatibility and these proteins can be subject to intense positive selection. In this review, we discuss what is known about the patterns of adaptive evolution of gamete recognition proteins (GRPs). We focus on species that broadcast eggs and sperm into the environment for external fertilization, as the ease of observing and manipulating gamete interactions has allowed for greater advances in the understanding of GRP evolution, uncomplicated by confounding behavioral and physiological components that offer alternative evolutionary targets in internal fertilizers. We discuss whether interspecific mechanisms, such as selection to avoid fertilization between species (reinforcement selection), or intraspecific mechanisms, such as selection to increase (or decrease) the affinity between eggs and sperm based on the intensity of sperm competition, may be responsible for the pattern of GRP evolution observed. Variation in these proteins appears to influence gametic compatibility; GRP divergence among species is a better predictor of hybrid fertilization than neutral genetic markers and GRP variation within species predicts reproductive success among individuals within a population. Evidence suggests that sperm competition may play a large role in the evolution of gametic compatibility.
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Affiliation(s)
- E T Kosman
- Department of Biological Science, Florida State University, Tallahassee, FL 32306, USA
| | - D R Levitan
- Department of Biological Science, Florida State University, Tallahassee, FL 32306, USA
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20
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Popovic I, Marko PB, Wares JP, Hart MW. Selection and demographic history shape the molecular evolution of the gamete compatibility protein bindin in Pisaster sea stars. Ecol Evol 2014; 4:1567-88. [PMID: 24967076 PMCID: PMC4063459 DOI: 10.1002/ece3.1042] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Revised: 02/15/2014] [Accepted: 02/26/2014] [Indexed: 12/18/2022] Open
Abstract
Reproductive compatibility proteins have been shown to evolve rapidly under positive selection leading to reproductive isolation, despite the potential homogenizing effects of gene flow. This process has been implicated in both primary divergence among conspecific populations and reinforcement during secondary contact; however, these two selective regimes can be difficult to discriminate from each other. Here, we describe the gene that encodes the gamete compatibility protein bindin for three sea star species in the genus Pisaster. First, we compare the full-length bindin-coding sequence among all three species and analyze the evolutionary relationships between the repetitive domains of the variable second bindin exon. The comparison suggests that concerted evolution of repetitive domains has an effect on bindin divergence among species and bindin variation within species. Second, we characterize population variation in the second bindin exon of two species: We show that positive selection acts on bindin variation in Pisaster ochraceus but not in Pisaster brevispinus, which is consistent with higher polyspermy risk in P. ochraceus. Third, we show that there is no significant genetic differentiation among populations and no apparent effect of sympatry with congeners that would suggest selection based on reinforcement. Fourth, we combine bindin and cytochrome c oxidase 1 data in isolation-with-migration models to estimate gene flow parameter values and explore the historical demographic context of our positive selection results. Our findings suggest that positive selection on bindin divergence among P. ochraceus alleles can be accounted for in part by relatively recent northward population expansions that may be coupled with the potential homogenizing effects of concerted evolution.
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Affiliation(s)
- Iva Popovic
- Department of Biological Sciences, Simon Fraser UniversityBurnaby, British Columbia, Canada
| | - Peter B Marko
- Department of Biology, University of Hawai'iMānoa, Hawaii
| | - John P Wares
- Department of Genetics, University of GeorgiaAthens, Georgia
| | - Michael W Hart
- Department of Biological Sciences, Simon Fraser UniversityBurnaby, British Columbia, Canada
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21
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Evans JP, Sherman CDH. Sexual selection and the evolution of egg-sperm interactions in broadcast-spawning invertebrates. THE BIOLOGICAL BULLETIN 2013; 224:166-183. [PMID: 23995741 DOI: 10.1086/bblv224n3p166] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Many marine invertebrate taxa are broadcast spawners, where multiple individuals release their gametes into the water for external fertilization, often in the presence of gametes from heterospecifics. Consequently, sperm encounter the considerable challenges of locating and fertilizing eggs from conspecific females. To overcome these challenges, many taxa exhibit species-specific attraction of sperm toward eggs through chemical signals released from eggs (sperm chemotaxis) and species-specific gamete recognition proteins (GRPs) that mediate compatibility of gametes at fertilization. In this prospective review, we highlight these selective forces, but also emphasize the role that sexual selection, manifested through sperm competition, cryptic female choice, and evolutionary conflicts of interest between the sexes (sexual conflict), can also play in mediating the action of egg chemoattractants and GRPs, and thus individual reproductive fitness. Furthermore, we explore patterns of selection at the level of gametes (sperm phenotype, gamete plasticity, and egg traits) to identify putative traits targeted by sexual selection in these species. We conclude by emphasizing the excellent, but relatively untapped, potential of broadcast-spawning marine invertebrates as model systems to illuminate several areas of research in post-mating sexual selection.
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Affiliation(s)
- Jonathan P Evans
- Centre for Evolutionary Biology, School of Animal Biology, University of Western Australia, Crawley, Australia.
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22
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Hart MW. Structure and evolution of the sea star egg receptor for sperm bindin. Mol Ecol 2013; 22:2143-56. [PMID: 23432510 DOI: 10.1111/mec.12251] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Revised: 01/10/2013] [Accepted: 01/12/2013] [Indexed: 02/03/2023]
Abstract
Selection on coevolving sperm- and egg-recognition molecules is a potent engine of population divergence leading to reproductive isolation and speciation. The study of receptor-ligand pairs can reveal co-evolution of male- and female-expressed genes or differences between their evolution in response to selective factors such as sperm competition and sexual conflict. Phylogeographical studies of these patterns have been limited by targeted gene methods that favour short protein-coding sequences amplifiable by PCR. Here, I use high-throughput transcriptomic methods to characterize the structure and divergence of full-length coding sequences for the gene encoding the protein component of a large complex egg surface glycopeptide receptor for the sperm acrosomal protein bindin from the sea star Patiria miniata. I used a simple but effective method for resolving nucleotide polymorphisms into haplotypes for phylogeny-based analyses of selection. The protein domain organization of sea star egg bindin receptor (EBR1) was similar to sea urchins and included a pair of protein-recognition domains plus a series of tandem repeat domains of two types. Two populations separated by a well-characterized phylogeographical break included lineages of EBR1 alleles under positive selection at several codons (similar to selection on sperm bindin in the same populations). However, these populations shared the same alleles that were under selection for amino acid differences at multiple codons (unlike the pattern of selection for population divergence in sperm bindin). The significance of positively selected EBR1 domains and alleles could be tested in functional analyses of fertilization rates associated with EBR1 (and bindin) polymorphisms.
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Affiliation(s)
- Michael W Hart
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada.
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23
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Aagaard JE, Springer SA, Soelberg SD, Swanson WJ. Duplicate abalone egg coat proteins bind sperm lysin similarly, but evolve oppositely, consistent with molecular mimicry at fertilization. PLoS Genet 2013; 9:e1003287. [PMID: 23408913 PMCID: PMC3567151 DOI: 10.1371/journal.pgen.1003287] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2012] [Accepted: 12/14/2012] [Indexed: 12/22/2022] Open
Abstract
Sperm and egg proteins constitute a remarkable paradigm in evolutionary biology: despite their fundamental role in mediating fertilization (suggesting stasis), some of these molecules are among the most rapidly evolving ones known, and their divergence can lead to reproductive isolation. Because of strong selection to maintain function among interbreeding individuals, interacting fertilization proteins should also exhibit a strong signal of correlated divergence among closely related species. We use evidence of such molecular co-evolution to target biochemical studies of fertilization in North Pacific abalone (Haliotis spp.), a model system of reproductive protein evolution. We test the evolutionary rates (dN/dS) of abalone sperm lysin and two duplicated egg coat proteins (VERL and VEZP14), and find a signal of co-evolution specific to ZP-N, a putative sperm binding motif previously identified by homology modeling. Positively selected residues in VERL and VEZP14 occur on the same face of the structural model, suggesting a common mode of interaction with sperm lysin. We test this computational prediction biochemically, confirming that the ZP-N motif is sufficient to bind lysin and that the affinities of VERL and VEZP14 are comparable. However, we also find that on phylogenetic lineages where lysin and VERL evolve rapidly, VEZP14 evolves slowly, and vice versa. We describe a model of sexual conflict that can recreate this pattern of anti-correlated evolution by assuming that VEZP14 acts as a VERL mimic, reducing the intensity of sexual conflict and slowing the co-evolution of lysin and VERL. Interacting sperm and egg proteins must co-evolve to maintain compatibility at fertilization, so their divergence among species should be correlated—lineages with rapidly evolving sperm proteins should have rapidly evolving egg proteins. We use this expectation to target biochemical studies of fertilization in a model system (abalone). We study a discrete functional domain (ZP-N) found in a pair of duplicated egg coat proteins, and we find the ZP-N motif from both proteins bind sperm lysin (a protein important for sperm passage of the egg coat) in a similar fashion. ZP-N is a feature of vertebrate and invertebrate egg coat proteins, as well as yeast mating recognition proteins, demonstrating its broad significance in sexual reproduction. Unexpectedly, we find that the ZP-N motifs of VEZP14 and VERL exhibit inverse patterns of co-evolution with lysin, suggesting that these duplicates may have opposite functions in fertilization. Using computer simulations, we model a novel explanation for this pattern whereby VEZP14 acts as a decoy of VERL in order to decrease the effective amount of sperm lysin and slow the rate of fertilization. Such molecular mimicry could complement other well-established fertilization blocks that females use to control rates of fertilization and limit polyspermy.
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Affiliation(s)
- Jan E Aagaard
- Department of Genome Sciences, University of Washington, Seattle, Washington, USA.
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24
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Anantharaman S, Craft JA. Annual variation in the levels of transcripts of sex-specific genes in the mantle of the common mussel, Mytilus edulis. PLoS One 2012; 7:e50861. [PMID: 23226407 PMCID: PMC3511322 DOI: 10.1371/journal.pone.0050861] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Accepted: 10/29/2012] [Indexed: 12/30/2022] Open
Abstract
Mytilus species are used as sentinels for the assessment of environmental health but sex or stage in the reproduction cycle is rarely considered even though both parameters are likely to influence responses to pollution. We have validated the use of a qPCR assay for sex identification and related the levels of transcripts to the reproductive cycle. A temporal study of mantle of Mytilus edulis found transcripts of male-specific vitelline coat lysin (VCL) and female-specific vitelline envelope receptor for lysin (VERL) could identify sex over a complete year. The levels of VCL/VERL were proportional to the numbers of sperm/ova and are indicative of the stage of the reproductive cycle. Maximal levels of VCL and VERL were found in February 2009 declining to minima between July - August before increasing and re-attaining a peak in February 2010. Water temperature may influence these transitions since they coincide with minimal water temperature in February and maximal temperature in August. An identical pattern of variation was found for a cryptic female-specific transcript (H5) but a very different pattern was observed for oestrogen receptor 2 (ER2). ER2 varied in a sex-specific way with male > female for most of the cycle, with a female maxima in July and a male maxima in December. Using artificially spawned animals, the transcripts for VCL, VERL and H5 were shown to be present in gametes and thus their disappearance from mantle is indicative of spawning. VCL and VERL are present at equivalent levels in February and July-August but during gametogenesis (August to January) and spawning (March to June) VCL is present at lower relative amounts than VERL. This may indicate sex-specific control mechanisms for these processes and highlight a potential pressure point leading to reduced reproductive output if environmental factors cause asynchrony to gamete maturation or release.
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25
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Ngernsoungnern P, Ngernsoungnern A, Chaiseha Y, Sretarugsa P. Role of vitelline envelope during fertilization in the black tiger shrimp, Penaeus monodon. Acta Histochem 2012; 114:659-64. [PMID: 22178117 DOI: 10.1016/j.acthis.2011.11.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2011] [Revised: 11/21/2011] [Accepted: 11/22/2011] [Indexed: 12/12/2022]
Abstract
Animal eggs possess investments through which sperm must penetrate. The aim of the present study was to investigate the role of the egg coating, the vitelline envelope, during sperm-egg interactions in the black tiger shrimp, Penaeus monodon. The site(s) of primary binding between sperm and egg and the possible binding molecule(s) for sperm were identified. In vitro adsorption of the vitelline envelope protein onto the sperm surface showed that primary binding occurred between the sperm anterior spike of acrosome intact sperm and the vitelline envelope. Results from streptavidin blotting revealed that the component of the vitelline envelope that interacts with the sperm integral membrane protein is a 370kDa protein. In addition, it was shown that the vitelline envelope protein had no ability to induce acrosome reaction. These results suggest that the function of the vitelline envelope is as a primary binding site for sperm in shrimp, but not a sole trigger for the acrosome reaction.
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Affiliation(s)
- Piyada Ngernsoungnern
- School of Biology, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, Thailand
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26
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Hart MW, Popovic I, Emlet RB. LOW RATES OF BINDIN CODON EVOLUTION IN LECITHOTROPHIC HELIOCIDARIS SEA URCHINS. Evolution 2012; 66:1709-21. [DOI: 10.1111/j.1558-5646.2012.01606.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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27
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Hellberg ME, Dennis AB, Arbour-Reily P, Aagaard JE, Swanson WJ. The Tegula tango: a coevolutionary dance of interacting, positively selected sperm and egg proteins. Evolution 2012; 66:1681-94. [PMID: 22671539 DOI: 10.1111/j.1558-5646.2011.01530.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Reproductive proteins commonly show signs of rapid divergence driven by positive selection. The mechanisms driving these changes have remained ambiguous in part because interacting male and female proteins have rarely been examined. We isolate an egg protein the vitelline envelope receptor for lysin (VERL) from Tegula, a genus of free-spawning marine snails. Like VERL from abalone, Tegula VERL is a major component of the VE surrounding the egg, includes a conserved zona pellucida (ZP) domain at its C-terminus, and possesses a unique, negatively charged domain of about 150 amino acids implicated in interactions with the positively charged lysin. Unlike for abalone VERL, where this unique VERL domain occurs in a tandem array of 22 repeats, Tegula VERL has just one such domain. Interspecific comparisons show that both lysin and the VERL domain diverge via positive selection, whereas the ZP domain evolves neutrally. Rates of nonsynonymous substitution are correlated between lysin and the VERL domain, consistent with sexual antagonism, although lineage-specific effects, perhaps owing to different ecologies, may alter the relative evolutionary rates of sperm- and egg-borne proteins.
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Affiliation(s)
- Michael E Hellberg
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana 70803, USA.
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28
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Vacquier VD, Swanson WJ. Selection in the rapid evolution of gamete recognition proteins in marine invertebrates. Cold Spring Harb Perspect Biol 2011; 3:a002931. [PMID: 21730046 PMCID: PMC3220358 DOI: 10.1101/cshperspect.a002931] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Animal fertilization is governed by the interaction (binding) of proteins on the surfaces of sperm and egg. In many examples presented herein, fertilization proteins evolve rapidly and show the signature of positive selection (adaptive evolution). This review describes the molecular evolution of fertilization proteins in sea urchins, abalone, and oysters, animals with external fertilization that broadcast their gametes into seawater. Theories regarding the selective forces responsible for the rapid evolution driven by positive selection seen in many fertilization proteins are discussed. This strong selection acting on divergence of interacting fertilization proteins might lead to prezygotic reproductive isolation and be a significant factor in the speciation process. Since only a fraction of all eggs are fertilized and only an infinitesimal fraction of male gametes succeed in fertilizing an egg, gametes are obviously a category of entities subjected to intense selection. It is curious that this is never mentioned in the literature dealing with selection, perhaps because we know so little about fitness differences among gametes. (Ernst Mayr, 1997).
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Affiliation(s)
- Victor D Vacquier
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California 92093-0202, USA.
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29
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Monné M, Jovine L. A structural view of egg coat architecture and function in fertilization. Biol Reprod 2011; 85:661-9. [PMID: 21715714 DOI: 10.1095/biolreprod.111.092098] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Species-restricted interaction between gametes at the beginning of fertilization is mediated by the extracellular coat of the egg, a matrix of cross-linked glycoprotein filaments called the zona pellucida (ZP) in mammals and the vitelline envelope in nonmammals. All egg coat subunits contain a conserved protein-protein interaction module-the "ZP domain"-that allows them to polymerize upon dissociation of a C-terminal propeptide containing an external hydrophobic patch (EHP). Recently, the first crystal structures of a ZP domain protein, sperm receptor ZP subunit zona pellucida glycoprotein 3 (ZP3), have been reported, giving a glimpse of the structural organization of the ZP at the atomic level and the molecular basis of gamete recognition in vertebrates. The ZP module is divided in two related immunoglobulin-like domains, ZP-N and ZP-C, that contain characteristic disulfide bond patterns and, in the case of ZP-C, also incorporate the EHP. This segment lies at the interface between the two domains, which are connected by a long loop carrying a conserved O-glycan important for binding to sperm in vitro. The structures explain several apparently contradictory observations by reconciling the variable disulfide bond patterns found in different homologues of ZP3 as well as the multiple ZP3 determinants alternatively involved in gamete interaction. These findings have implications for our understanding of ZP subunit biogenesis; egg coat assembly, architecture, and interaction with sperm; structural rearrangements leading to postfertilization hardening of the ZP and the block to sperm binding; and the evolutionary origin of egg coats.
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Affiliation(s)
- Magnus Monné
- Department of Biosciences and Nutrition and Center for Biosciences, Karolinska Institutet, Huddinge, Sweden
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Swanson WJ, Aagaard JE, Vacquier VD, Monné M, Sadat Al Hosseini H, Jovine L. The molecular basis of sex: linking yeast to human. Mol Biol Evol 2011; 28:1963-6. [PMID: 21282709 DOI: 10.1093/molbev/msr026] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Species-specific recognition between egg and sperm, a crucial event that marks the beginning of fertilization in multicellular organisms, mirrors the binding between haploid cells of opposite mating type in unicellular eukaryotes such as yeast. However, as implied by the lack of sequence similarity between sperm-binding regions of invertebrate and vertebrate egg coat proteins, these interactions are thought to rely on completely different molecular entities. Here, we argue that these recognition systems are, in fact, related: despite being separated by 0.6-1 billion years of evolution, functionally essential domains of a mollusc sperm receptor and a yeast mating protein adopt the same 3D fold as egg zona pellucida proteins mediating the binding between gametes in humans.
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Aagaard JE, Vacquier VD, MacCoss MJ, Swanson WJ. ZP domain proteins in the abalone egg coat include a paralog of VERL under positive selection that binds lysin and 18-kDa sperm proteins. Mol Biol Evol 2010; 27:193-203. [PMID: 19767347 DOI: 10.1093/molbev/msp221] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Identifying fertilization molecules is key to our understanding of reproductive biology, yet only a few examples of interacting sperm and egg proteins are known. One of the best characterized comes from the invertebrate archeogastropod abalone (Haliotis spp.), where sperm lysin mediates passage through the protective egg vitelline envelope (VE) by binding to the VE protein vitelline envelope receptor for lysin (VERL). Rapid adaptive divergence of abalone lysin and VERL are an example of positive selection on interacting fertilization proteins contributing to reproductive isolation. Previously, we characterized a subset of the abalone VE proteins that share a structural feature, the zona pellucida (ZP) domain, which is common to VERL and the egg envelopes of vertebrates. Here, we use additional expressed sequence tag sequencing and shotgun proteomics to characterize this family of proteins in the abalone egg VE. We expand 3-fold the number of known ZP domain proteins present within the VE (now 30 in total) and identify a paralog of VERL (vitelline envelope zona pellucida domain protein [VEZP] 14) that contains a putative lysin-binding motif. We find that, like VERL, the divergence of VEZP14 among abalone species is driven by positive selection on the lysin-binding motif alone and that these paralogous egg VE proteins bind a similar set of sperm proteins including a rapidly evolving 18-kDa paralog of lysin, which may mediate sperm-egg fusion. This work identifies an egg coat paralog of VERL under positive selection and the candidate sperm proteins with which it may interact during abalone fertilization.
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Affiliation(s)
- Jan E Aagaard
- Department of Genome Sciences, University of Washington, USA.
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32
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The rate of unequal crossing over in the dumpy gene from Drosophila melanogaster. J Mol Evol 2010; 70:260-5. [PMID: 20204610 DOI: 10.1007/s00239-010-9327-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2009] [Accepted: 02/10/2010] [Indexed: 10/19/2022]
Abstract
The PIGSFEAST (PF) exon of the Drosophila dumpy gene is undergoing concerted evolution by the process of unequal crossing over. We have developed a long-range PCR-based assay to amplify the approximately 12 kb long exon which contains variable numbers of 303 or 306 nt long repeats in a tandem array. We applied this procedure to mutation accumulation lines of Drosophila melanogaster established by M. Wayne and L. Higgins. Nine new repeat length variants were found in these lines allowing us to measure the rate of unequal crossing over in the PF exon. The rate, which for several reasons is an underestimate, is 7.05 x 10(-4) exchanges per generation.
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Clark NL, Gasper J, Sekino M, Springer SA, Aquadro CF, Swanson WJ. Coevolution of interacting fertilization proteins. PLoS Genet 2009; 5:e1000570. [PMID: 19629160 PMCID: PMC2704960 DOI: 10.1371/journal.pgen.1000570] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2008] [Accepted: 06/23/2009] [Indexed: 01/01/2023] Open
Abstract
Reproductive proteins are among the fastest evolving in the proteome, often due to the consequences of positive selection, and their rapid evolution is frequently attributed to a coevolutionary process between interacting female and male proteins. Such a process could leave characteristic signatures at coevolving genes. One signature of coevolution, predicted by sexual selection theory, is an association of alleles between the two genes. Another predicted signature is a correlation of evolutionary rates during divergence due to compensatory evolution. We studied female-male coevolution in the abalone by resequencing sperm lysin and its interacting egg coat protein, VERL, in populations of two species. As predicted, we found intergenic linkage disequilibrium between lysin and VERL, despite our demonstration that they are not physically linked. This finding supports a central prediction of sexual selection using actual genotypes, that of an association between a male trait and its female preference locus. We also created a novel likelihood method to show that lysin and VERL have experienced correlated rates of evolution. These two signatures of coevolution can provide statistical rigor to hypotheses of coevolution and could be exploited for identifying coevolving proteins a priori. We also present polymorphism-based evidence for positive selection and implicate recent selective events at the specific structural regions of lysin and VERL responsible for their species-specific interaction. Finally, we observed deep subdivision between VERL alleles in one species, which matches a theoretical prediction of sexual conflict. Thus, abalone fertilization proteins illustrate how coevolution can lead to reproductive barriers and potentially drive speciation.
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Affiliation(s)
- Nathaniel L. Clark
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, United States of America
| | - Joe Gasper
- Department of Genome Sciences, University of Washington, Seattle, Washington, United States of America
| | - Masashi Sekino
- Tohoku National Fisheries Research Institute, Fisheries Research Agency, Shiogama, Miyagi, Japan
| | - Stevan A. Springer
- Department of Genome Sciences, University of Washington, Seattle, Washington, United States of America
| | - Charles F. Aquadro
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, United States of America
| | - Willie J. Swanson
- Department of Genome Sciences, University of Washington, Seattle, Washington, United States of America
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Abstract
This selective review considers herpetological papers that feature the use of chemical cues, particularly pheromones involved in reproductive interactions between potential mates. Primary examples include garter snake females that attract males, lacertid lizards and the effects of their femoral gland secretions, aquatic male newts that chemically attract females, and terrestrial salamander males that chemically persuade a female to mate. Each case study spans a number of research approaches (molecular, biochemical, behavioral) and is related to sensory processing and the physiological effects of pheromone delivery. These and related studies show that natural pheromones can be identified, validated with behavioral tests, and incorporated in research on vomeronasal functional response.
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Affiliation(s)
- Lynne D Houck
- Department of Zoology, Oregon State University, Corvallis, Oregon 97331, USA.
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35
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Forensic genetic identification of abalone (Haliotis spp.) of the northeastern Pacific Ocean. CONSERV GENET 2009. [DOI: 10.1007/s10592-009-9925-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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36
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Palumbi SR. Speciation and the evolution of gamete recognition genes: pattern and process. Heredity (Edinb) 2008; 102:66-76. [PMID: 19018273 DOI: 10.1038/hdy.2008.104] [Citation(s) in RCA: 140] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Proteins on gamete surfaces are major determinants of fertilization success, particularly in free-spawning animals. Molecular analyses of these simple genetic systems show rapid evolution, positive selection, accelerated coalescence and, sometimes, extensive polymorphism. Careful analysis of the behavior of sperm produced by males with different gamete alleles shows that these alleles can deliver significant functional differences. Three forms of allele-specific fertilization advantage have been shown: assortative mating based on gamete type, rare allele advantage and heterozygote superiority. Models suggest that sperm and egg proteins may be coevolutionary partners that can alternate between directional selection for high fertilization ability and cyclic adaptation of eggs and sperm driven by sexual conflict. These processes act within allopatric populations and may accelerate their divergence if gamete adaptations in separate demes reduce cross-fertilization. Reproductive character displacement by reinforcement may play a diversifying role when previously allopatric populations rejoin. In circumstance that might prove to be common, divergence in sympatry can be driven by sexual conflict or by association of mating types with ecological differences. The ecology of fertilization, especially the degree of sperm competition and egg death via polyspermy, are important determinants of the strength and direction of selection on gametes. Free-spawning animals allow careful analysis of gamete recognition -from the behavior of adults and interactions of gametes, to molecular patterns of allele divergence. Future research efforts on the evolutionary consequences of fertilization ecology, and the interaction between extensive variation in egg surface proteins and sperm fertilization ability, are particularly needed.
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Affiliation(s)
- S R Palumbi
- Department of Biology, Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950, USA.
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Hirohashi N, Kamei N, Kubo H, Sawada H, Matsumoto M, Hoshi M. Egg and sperm recognition systems during fertilization. Dev Growth Differ 2008; 50 Suppl 1:S221-38. [DOI: 10.1111/j.1440-169x.2008.01017.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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38
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Kelleher ES, Swanson WJ, Markow TA. Gene duplication and adaptive evolution of digestive proteases in Drosophila arizonae female reproductive tracts. PLoS Genet 2007; 3:e148. [PMID: 17784792 PMCID: PMC1959364 DOI: 10.1371/journal.pgen.0030148] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2007] [Accepted: 07/13/2007] [Indexed: 01/04/2023] Open
Abstract
It frequently has been postulated that intersexual coevolution between the male ejaculate and the female reproductive tract is a driving force in the rapid evolution of reproductive proteins. The dearth of research on female tracts, however, presents a major obstacle to empirical tests of this hypothesis. Here, we employ a comparative EST approach to identify 241 candidate female reproductive proteins in Drosophila arizonae, a repleta group species in which physiological ejaculate–female coevolution has been documented. Thirty-one of these proteins exhibit elevated amino acid substitution rates, making them candidates for molecular coevolution with the male ejaculate. Strikingly, we also discovered 12 unique digestive proteases whose expression is specific to the D. arizonae lower female reproductive tract. These enzymes belong to classes most commonly found in the gastrointestinal tracts of a diverse array of organisms. We show that these proteases are associated with recent, lineage-specific gene duplications in the Drosophila repleta species group, and exhibit strong signatures of positive selection. Observation of adaptive evolution in several female reproductive tract proteins indicates they are active players in the evolution of reproductive tract interactions. Additionally, pervasive gene duplication, adaptive evolution, and rapid acquisition of a novel digestive function by the female reproductive tract points to a novel coevolutionary mechanism of ejaculate–female interaction. In a broad range of organisms, including humans, molecular interactions between the male ejaculate and the female reproductive tract play integral roles in sexual reproduction. Although these interactions are essential, the biochemical composition of the male ejaculate can change rapidly over short evolutionary time periods. It is often hypothesized that this rapid evolution reflects a coevolutionary relationship with the female reproductive tract. The paucity of research on females, however, presents a formidable challenge to empirical tests of this hypothesis. In this study, we sought to identify proteins in the female reproductive tracts of D. arizonae that may be interacting or coevolving with the male ejaculate. Unexpectedly, we discovered that D. arizonae females produce an array of “digestive” enzymes in their reproductive tracts. These classes of enzymes are normally found in the gut, where they degrade ingested food for nutritional uptake. In D. arizonae, these enzymes have resulted from recent gene duplications, and natural selection has caused rapid and radical changes in their amino acid sequences. We propose that this pattern of duplication and diversification reflects the “female side” of a coevolutionary relationship with the male ejaculate. Exploring the “male side” of this relationship is an important avenue for future research.
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Affiliation(s)
- Erin S Kelleher
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, Arizona, United States of America.
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39
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Abstract
Sexual conflict has been suggested as a general cause of genetic diversification in reproductive characters, and as a possible cause of speciation. We use individual-based simulations to study the dynamics of sexual conflict in an isolated diploid population with no spatial structure. To explore the effects of genetic details, we consider two different types of interlocus interaction between female and male traits, and three different types of intra-locus interaction. In the simulations, sexual conflict resulted in at least the following five regimes: (1) continuous coevolutionary chase, (2) evolution toward an equilibrium, (3) cyclic coevolution, (4) extensive genetic differentiation in female traits/genes only, and (5) extensive genetic differentiation in both male and female traits/genes. Genetic differentiation was hardly observed when the traits involved in reproduction were determined additively and interacted in a trait-by-trait way. When the traits interacted in a component-by-component way, genetic differentiation was frequently observed under relatively broad conditions. The likelihood of genetic differentiation largely depended on the number of loci and the type of within-locus dominance. With multiple loci per trait, genetic differentiation was often observed but sympatric speciation was typically hindered by recombination. Sympatric speciation was possible but only under restrictive conditions. Our simulations also highlight the importance of stochastic effects in the dynamics of sexual conflict.
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Affiliation(s)
- Takehiko I Hayashi
- Research Center for Chemical Risk Management, National Institute of Advanced Industrial Science and Technology, 16-1 Onogawa, Tsukuba, Ibaraki 305-8589, Japan.
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Carmon A, Wilkin M, Hassan J, Baron M, MacIntyre R. Concerted evolution within the Drosophila dumpy gene. Genetics 2007; 176:309-25. [PMID: 17237523 PMCID: PMC1893059 DOI: 10.1534/genetics.106.060897] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We have determined by reverse Southern analysis and direct sequence comparisons that most of the dumpy gene has evolved in the dipteran and other insect orders by purifying selection acting on amino acid replacements. One region, however, is evolving rapidly due to unequal crossing over and/or gene conversion. This region, called "PIGSFEAST," or PF, encodes in D. melanogaster 30-47 repeats of 102 amino acids rich in serines, threonines, and prolines. We show that the processes of concerted evolution have been operating on all species of Drosophila examined to date, but that an adjacent region has expanded in Anopheles gambiae, Aedes aegypti, and Tribolium castaneum, while the PF repeats are reduced in size and number. In addition, processes of concerted evolution have radically altered the codon usage patterns in D. melanogaster, D. pseudoobscura, and D. virilis compared with the rest of the dumpy gene. We show also that the dumpy gene is expressed on the inner surface of the micropyle of the mature oocyte and propose that, as in the abalone system, concerted evolution may be involved in adaptive changes affecting Dumpy's possible role in sperm-egg recognition.
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Affiliation(s)
- Amber Carmon
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
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41
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Aagaard JE, Yi X, MacCoss MJ, Swanson WJ. Rapidly evolving zona pellucida domain proteins are a major component of the vitelline envelope of abalone eggs. Proc Natl Acad Sci U S A 2006; 103:17302-7. [PMID: 17085584 PMCID: PMC1859926 DOI: 10.1073/pnas.0603125103] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Proteins harboring a zona pellucida (ZP) domain are prominent components of vertebrate egg coats. Although less well characterized, the egg coat of the non-vertebrate marine gastropod abalone (Haliotis spp.) is also known to contain a ZP domain protein, raising the possibility of a common molecular basis of metazoan egg coat structures. Egg coat proteins from vertebrate as well as non-vertebrate taxa have been shown to evolve under positive selection. Studied most extensively in the abalone system, coevolution between adaptively diverging egg coat and sperm proteins may contribute to the rapid development of reproductive isolation. Thus, identifying the pattern of evolution among egg coat proteins is important in understanding the role these genes may play in the speciation process. The purpose of the present study is to characterize the constituent proteins of the egg coat [vitelline envelope (VE)] of abalone eggs and to provide preliminary evidence regarding how selection has acted on VE proteins during abalone evolution. A proteomic approach is used to match tandem mass spectra of peptides from purified VE proteins with abalone ovary EST sequences, identifying 9 of 10 ZP domain proteins as components of the VE. Maximum likelihood models of codon evolution suggest positive selection has acted among a subset of amino acids for 6 of these genes. This work provides further evidence of the prominence of ZP proteins as constituents of the egg coat, as well as the prominent role of positive selection in diversification of these reproductive proteins.
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Affiliation(s)
- Jan E Aagaard
- Department of Genome Sciences, University of Washington, Box 357730, Seattle, WA 98195, USA.
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42
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Riginos C, Wang D, Abrams AJ. Geographic Variation and Positive Selection on M7 Lysin, an Acrosomal Sperm Protein in Mussels (Mytilus spp.). Mol Biol Evol 2006; 23:1952-65. [PMID: 16855010 DOI: 10.1093/molbev/msl062] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Successful fertilization in free-spawning marine organisms depends on the interactions between genes expressed on the surfaces of eggs and sperm. Positive selection frequently characterizes the molecular evolution of such genes, raising the possibility that some common deterministic process drives the evolution of gamete recognition genes and may even be important for understanding the evolution of prezygotic isolation and speciation in the marine realm. One hypothesis is that gamete recognition genes are subject to selection for prezygotic isolation, namely, reinforcement. In a previous study, positive selection on the gene coding for the acrosomal sperm protein M7 lysin was demonstrated among allopatric populations of mussels in the Mytilus edulis species group (M. edulis, Mytilus galloprovincialis, and Mytilus trossulus). Here, we expand sampling to include M7 lysin haplotypes from populations where mussel species are sympatric and hybridize to determine whether there is a pattern of reproductive character displacement (RCD), which would be consistent with reinforcement driving selection on this gene. We do not detect a strong pattern of RCD; neither are there unique haplotypes in sympatry nor is there consistently greater population structure in comparisons involving sympatric populations. One distinct group of haplotypes, however, is strongly affected by natural selection, and this group of haplotypes is found within M. galloprovincialis populations throughout the Northern Hemisphere concurrent with haplotypes common to M. galloprovincialis and M. edulis. We suggest that balancing selection, perhaps resulting from sexual conflicts between sperm and eggs, maintains old allelic diversity within M. galloprovincialis.
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Panhuis TM, Clark NL, Swanson WJ. Rapid evolution of reproductive proteins in abalone and Drosophila. Philos Trans R Soc Lond B Biol Sci 2006; 361:261-8. [PMID: 16612885 PMCID: PMC1569613 DOI: 10.1098/rstb.2005.1793] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Observations from different taxa, including plants, protozoa, insects and mammals, indicate that proteins involved in reproduction evolve rapidly. Several models of adaptive evolution have been proposed to explain this phenomenon, such as sexual conflict, sexual selection, self versus non-self recognition and pathogen resistance. Here we discuss the potential role of sexual conflict in the rapid evolution of reproductive genes in two different animal systems, abalone (Haliotis) and Drosophila. In abalone, we reveal how specific interacting sperm-egg proteins were identified and discuss this identification in the light of models for rapid protein evolution and speciation. For Drosophila, we describe the genomic approaches taken to identify male accessory gland proteins and female reproductive tract proteins. Patterns of protein evolution from both abalone and Drosophila support the predicted patterns of rapid protein evolution driven by sexual conflict. We stress however that other selective pressures may contribute to the rapid evolution that is observed. We conclude that the key to distinguishing between sexual conflict and other mechanisms of protein evolution will be an integration of genetic, experimental and theoretical data.
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Affiliation(s)
| | | | - Willie J Swanson
- Department of Genome Sciences, University of WashingtonPO Box 357730, Seattle, WA 98195-7730, USA
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44
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Abstract
Many eukaryotic proteins share a sequence designated as the zona pellucida (ZP) domain. This structural element, present in extracellular proteins from a wide variety of organisms, from nematodes to mammals, consists of approximately 260 amino acids with eight conserved cysteine (Cys) residues and is located close to the C terminus of the polypeptide. ZP domain proteins are often glycosylated, modular structures consisting of multiple types of domains. Predictions can be made about some of the structural features of the ZP domain and ZP domain proteins. The functions of ZP domain proteins vary tremendously, from serving as structural components of egg coats, appendicularian mucous houses, and nematode dauer larvae, to serving as mechanotransducers in flies and receptors in mammals and nonmammals. Generally, ZP domain proteins are present in filaments and/or matrices, which is consistent with the role of the domain in protein polymerization. A general mechanism for assembly of ZP domain proteins has been presented. It is likely that the ZP domain plays a common role despite its presence in proteins of widely diverse functions.
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Affiliation(s)
- Luca Jovine
- Brookdale Department of Molecular, Cell, and Developmental Biology, Mount Sinai School of Medicine, New York, New York 10029-6574, USA.
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45
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Ban S, Harada Y, Yokosawa H, Sawada H. Highly polymorphic vitelline-coat protein HaVC80 from the ascidian, Halocynthia aurantium: structural analysis and involvement in self/nonself recognition during fertilization. Dev Biol 2005; 286:440-51. [PMID: 16154559 DOI: 10.1016/j.ydbio.2005.08.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2005] [Revised: 07/17/2005] [Accepted: 08/01/2005] [Indexed: 11/21/2022]
Abstract
Ascidians release sperm and eggs simultaneously, but self-fertilization is effectively blocked by unknown mechanisms. We previously reported that a 70-kDa sperm receptor HrVC70 on the egg vitelline coat (VC) consisting of 12 EGF-like repeats is a candidate self/nonself recognition molecule during fertilization of the ascidian, Halocynthia roretzi. Here, we report that Halocynthia aurantium also utilizes a homolog (HaVC80) of HrVC70 as an allorecognizable sperm receptor. HaVC80 is attached to the VC during the acquisition of self-sterility and is detached from the VC by acid treatment, allowing self-fertilization. A cDNA clone of the HaVC80 precursor, HaVC130, consists of 3726 nucleotides and encodes an open reading frame of 1208 amino acids. The structure of HaVC130 is very similar to the HrVC70 precursor HrVC120, but the number of EGF-like repeats of HaVC130/VC80 is one repeat larger than that of HrVC120/VC70. There are several amino acid substitutions between different individuals, and two alleles of the HaVC80 sequence were detected in each individual. Genomic DNA sequence analysis reveals that each EGF-like domain corresponds to a specific exon, and HaVC130 may have been evolutionarily generated from HrVC120 by duplication of the 8th EGF-like repeat. The data support the hypothesis that HaVC80 is a highly polymorphic protein responsible for self-sterility in H. aurantium.
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Affiliation(s)
- Susumu Ban
- Sugashima Marine Biological Laboratory, Graduate School of Science, Nagoya University, Sugashima, Toba 517-0004, Japan
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46
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Johannesson H, Townsend JP, Hung CY, Cole GT, Taylor JW. Concerted evolution in the repeats of an immunomodulating cell surface protein, SOWgp, of the human pathogenic fungi Coccidioides immitis and C. posadasii. Genetics 2005; 171:109-17. [PMID: 15965255 PMCID: PMC1456504 DOI: 10.1534/genetics.105.040923] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Genome dynamics that allow pathogens to escape host immune responses are fundamental to our understanding of host-pathogen interactions. Here we present the first population-based study of the process of concerted evolution in the repetitive domain of a protein-coding gene. This gene, SOWgp, encodes the immunodominant protein in the parasitic phase of the human pathogenic fungi Coccidioides immitis and C. posadasii. We sequenced the entire gene from strains representing the geographic ranges of the two Coccidioides species. By using phylogenetic and genetic distance analyses we discovered that the repetitive part of SOWgp evolves by concerted evolution, predominantly by the mechanism of unequal crossing over. We implemented a mathematical model originally developed for multigene families to estimate the rate of homogenization and recombination of the repetitive array, and the results indicate that the pattern of concerted evolution is a result of homogenization of repeat units proceeding at a rate close to the nucleotide point mutation rate. The release of the SOWgp molecules by the pathogen during proliferation may mislead the host: we speculate that the pathogen benefits from concerted evolution of repeated domains in SOWgp by an enhanced ability to misdirect the host's immune system.
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Affiliation(s)
- Hanna Johannesson
- Department of Evolution, Genomics and Systematics, Evolutionary Biology Centre, Uppsala University, Sweden.
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47
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Wong JL, Wessel GM. Major components of a sea urchin block to polyspermy are structurally and functionally conserved. Evol Dev 2005; 6:134-53. [PMID: 15099301 DOI: 10.1111/j.1525-142x.2004.04019.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
One sperm fusing with one egg is requisite for successful fertilization; additional sperm fusions are lethal to the embryo. Because sperm usually outnumber eggs, evolution has selected for mechanisms that prevent this polyspermy by immediately modifying the egg extracellular matrix. We focus here on the contribution of cortical granule contents in the sea urchin block to polyspermy to begin to understand how well this process is conserved. We identified each of the major constituents of the fertilization envelope in two species of seaurchins, Strongylocentrotus purpuratus and Lytechinus variegatus, that diverged 30 to 50 million years ago. Our results show that the five major structural components of the fertilization envelope, derived from the egg cortical granules, are semiconserved. Most of these orthologs share sequence identity and encode multiple low-density lipoprotein receptor type A repeats or CUB domains but at least two contain radically different carboxy-terminal repeats. Using a new association assay, we also show that these major structural components are functionally conserved during fertilization envelope construction. Thus, it seems that this population of female reproductive proteins has retained functional motifs while gaining significant sequence diversity-two opposing paths that may reflect cooperativity among the proteins that compose the fertilization envelope.
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Affiliation(s)
- Julian L Wong
- Department of Molecular Biology, Cellular Biology, and Biochemistry, Box G-J4, Brown University, Providence, RI 02912, USA
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Abstract
Fertilization is the union of a single sperm and an egg, an event that results in a diploid embryo. Animals use many mechanisms to achieve this ratio; the most prevalent involves physically blocking the fusion of subsequent sperm. Selective pressures to maintain monospermy have resulted in an elaboration of diverse egg and sperm structures. The processes employed for monospermy are as diverse as the animals that result from this process. Yet, the fundamental molecular requirements for successful monospermic fertilization are similar, implying that animals may have a common ancestral block to polyspermy. Here, we explore this hypothesis, reviewing biochemical, molecular, and genetic discoveries that lend support to a common ancestral mechanism. We also consider the evolution of alternative or radical techniques, including physiological polyspermy, with respect to our ability to describe a parsimonious guide to fertilization.
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Affiliation(s)
- Julian L Wong
- Department of Molecular Biology, Cellular Biology, and Biochemistry, Brown University, Providence, Rhode Island 02912, USA
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Galindo BE, Vacquier VD, Swanson WJ. Positive selection in the egg receptor for abalone sperm lysin. Proc Natl Acad Sci U S A 2003; 100:4639-43. [PMID: 12676995 PMCID: PMC153608 DOI: 10.1073/pnas.0830022100] [Citation(s) in RCA: 131] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The mechanism of speciation is a central problem in evolutionary biology. In free-spawning animals with no complex mating behavior, prezygotic reproductive isolation (speciation) could result from the rapid divergence of genes coding for sperm and egg proteins that bind each other during fertilization. In abalone, sperm lysin evolves rapidly by positive Darwinian selection. The egg vitelline envelope receptor for lysin had previously been shown to evolve neutrally and be subjected to concerted evolution. Several mathematical simulations predict that both male and female reproductive proteins should evolve rapidly by positive selection. Here we report that the sequence diversity of the amino-terminal end of the egg vitelline envelope receptor for lysin has been promoted by positive Darwinian selection. These data provide molecular support for theoretical models showing that the two sexes are locked in a "coevolutionary chase" that could be driven by processes such as sexual selection, sexual conflict, or microbial attack (pathogen avoidance). The result of this continuous coevolution of the gamete recognition system could be the splitting of one population into two that are reproductively isolated (speciation).
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Affiliation(s)
- Blanca E Galindo
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California at San Diego, La Jolla, CA 92093-0202, USA
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