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Hamilton LE, Suzuki J, Aguila L, Meinsohn MC, Smith OE, Protopapas N, Xu W, Sutovsky P, Oko R. Sperm-borne glutathione-S-transferase omega 2 accelerates the nuclear decondensation of spermatozoa during fertilization in mice†. Biol Reprod 2020; 101:368-376. [PMID: 31087045 DOI: 10.1093/biolre/ioz082] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 04/06/2019] [Accepted: 05/11/2019] [Indexed: 12/26/2022] Open
Abstract
The postacrosomal sheath (PAS) of the perinuclear theca (PT) is the first compartment of the sperm head to solubilize into the ooplasm upon sperm-oocyte fusion, implicating its constituents in zygotic development. This study investigates the role of one such constituent, glutathione-S-transferase omega 2 (GSTO2), an oxidative-reductive enzyme found in the PAS and perforatorial regions of the PT. GSTO2 uses the conjugation of reduced glutathione, an electron donor shown to be compulsory in sperm disassembly within the ooplasm. The proximity of GSTO2 to the condensed sperm nucleus led us to hypothesize that this enzyme may facilitate nuclear decondensation by reducing disulfide bonds before the recruitment of GSTO enzymes from within the ooplasm. To test this hypothesis, we utilized a cell permeable isozyme-specific inhibitor, which fluoresces when bound to the active site of GSTO2, to functionally inhibit spermatozoa before performing intracytoplasmic sperm injections (ICSI) in mice. The technique allowed for targeted inhibition of solely PT-residing GSTO2, as all that is required for complete zygotic development is the injection of the mouse spermatozoon head. ICSI showed that inhibition of PT-anchored GSTO2 caused a delay in sperm nuclear decondensation, and further resulted in untimely embryo cleavage, and an increase in fragmentation beginning at the morula stage. The confounding effects of these developmental delays ultimately resulted in decreased blastocyst formation. This study implicates PT-anchored GSTO2 as an important facilitator of nuclear decondensation and reinforces the notion that the PAS-PT is a critical sperm compartment harboring molecules that facilitate zygotic development.
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Affiliation(s)
- Lauren E Hamilton
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, K7L 3N6, Canada
| | - Joao Suzuki
- Department of Veterinary Sciences, Center for Research in Reproduction and Fertility, Université de Montreal, St. Hyacinthe, QC, J2S 2M2, Canada
| | - Luis Aguila
- Department of Veterinary Sciences, Center for Research in Reproduction and Fertility, Université de Montreal, St. Hyacinthe, QC, J2S 2M2, Canada
| | - Marie-Charlotte Meinsohn
- Department of Veterinary Sciences, Center for Research in Reproduction and Fertility, Université de Montreal, St. Hyacinthe, QC, J2S 2M2, Canada
| | - Olivia E Smith
- Department of Veterinary Sciences, Center for Research in Reproduction and Fertility, Université de Montreal, St. Hyacinthe, QC, J2S 2M2, Canada
| | - Nicole Protopapas
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, K7L 3N6, Canada
| | - Wei Xu
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, K7L 3N6, Canada
| | - Peter Sutovsky
- Division of Animal Sciences, College of Food, Agriculture and Natural Resources, and Department of Obstetrics, Gynecology and Women's Health, School of Medicine, University of Missouri, Columbia, MO,USA
| | - Richard Oko
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, K7L 3N6, Canada
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Protopapas N, Hamilton LE, Warkentin R, Xu W, Sutovsky P, Oko R. The perforatorium and postacrosomal sheath of rat spermatozoa share common developmental origins and protein constituents†. Biol Reprod 2020; 100:1461-1472. [PMID: 30939204 PMCID: PMC6561862 DOI: 10.1093/biolre/ioz052] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 03/01/2019] [Accepted: 03/29/2019] [Indexed: 01/27/2023] Open
Abstract
The perinuclear theca (PT) is a cytosolic protein capsule that surrounds the nucleus of eutherian spermatozoa. Compositionally, it is divided into two regions: the subacrosomal layer (SAL) and the postacrosomal sheath (PAS). In falciform spermatozoa, a third region of the PT emerges that extends beyond the nuclear apex called the perforatorium. The formation of the SAL and PAS differs, with the former assembling early in spermiogenesis concomitant with acrosome formation, and the latter dependent on manchette descent during spermatid elongation. The perforatorium also forms during the elongation phase of spermiogenesis, suggesting that like the PAS, its assembly is facilitated by the manchette. The temporal similarity in biogenesis between the PAS and perforatorium led us to compare their molecular composition using cell fractionation and immunodetection techniques. Although the perforatorium is predominantly composed of its endemic protein FABP9/PERF15, immunolocalization indicates that it also shares proteins with the PAS. These include WBP2NL/PAWP, WBP2, GSTO2, and core histones, which have been implicated in early fertilization and zygotic events. The compositional homogeny between the PAS and perforatorium supports our observation that their development is linked. Immunocytochemistry indicates that both PAS and perforatorial biogenesis depend on the transport and deposition of cytosolic proteins by the microtubular manchette. Proteins translocated from the manchette pass ventrally along the spermatid head into the apical perforatorial space prior to PAS deposition in the wake of manchette descent. Our findings demonstrate that the perforatorium and PAS share a mechanism of developmental assembly and thereby contain common proteins that facilitate fertilization.
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Affiliation(s)
- Nicole Protopapas
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Lauren E Hamilton
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Ruben Warkentin
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Wei Xu
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Peter Sutovsky
- Division of Animal Sciences, College of Agriculture, Food and Natural Resources, University of Missouri, Colombia, Missouri, USA.,Department of Obstetrics, Gynecology and Women's Health, School of Medicine, University of Missouri, Colombia, Missouri, USA
| | - Richard Oko
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
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Breed WG, Ding X, Tuke J, Leigh C. Morphological diversity of the spermatozoon and male reproductive tract in Australian Hopping mice, genus
Notomys
– is it determined by sexual selection? J Zool (1987) 2020. [DOI: 10.1111/jzo.12779] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- W. G. Breed
- School of Biological Sciences Faculty of Sciences and The Robinson Research Institute The University of Adelaide Adelaide SA Australia
| | - X. Ding
- Adelaide Medical School Faculty of Health and Medical Sciences The University of Adelaide Adelaide SA Australia
| | - J. Tuke
- School of Mathematical Sciences The University of Adelaide SA Australia
| | - C.M. Leigh
- Adelaide Medical School Faculty of Health and Medical Sciences The University of Adelaide Adelaide SA Australia
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4
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Peirce EJ, McLennan HJ, Tuke J, Leigh CM, Breed WG. Evolution of the testis and spermatozoon in mice and rats (Subfamily
Murinae
) in the absence of sperm competition. J Zool (1987) 2018. [DOI: 10.1111/jzo.12573] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- E. J. Peirce
- Adelaide Medical School Faculty of Health and Medical Sciences The University of Adelaide Adelaide SA Australia
| | - H. J. McLennan
- Adelaide Medical School Faculty of Health and Medical Sciences The University of Adelaide Adelaide SA Australia
| | - J. Tuke
- School of Mathematical Sciences The University of Adelaide Adelaide SA Australia
| | - C. M. Leigh
- Adelaide Medical School Faculty of Health and Medical Sciences The University of Adelaide Adelaide SA Australia
| | - W. G. Breed
- School of Biological Sciences Faculty of Sciences The University of Adelaide Adelaide SA Australia
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5
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Ferres KM, McPherson NO, Lane M, Bakos HW, Kind KL, Breed WG. Gamete cryopreservation of Australian 'old endemic' rodents – spermatozoa from the plains mouse (Pseudomys
australis) and spinifex hopping mouse (Notomys alexis). AUSTRALIAN MAMMALOGY 2018. [DOI: 10.1071/am16055] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Most of the Australian ‘old endemic’ rodents have greatly reduced distributions with several species now threatened with extinction. Application of assisted reproductive technology has the potential to assist in their conservation programs in at least a few species. Here we describe an attempt to cryopreserve spermatozoa from two of these species – those of the plains mouse (Pseudomys australis) and spinifex hopping mouse (Notomys alexis), which have dramatic differences in sperm morphology. Slow and rapid freezing and three different cryoprotectant media with either raffinose, glycerol and/or skim milk were used and the results compared with those of house mouse sperm, which were used as controls. Sperm morphology, motility, membrane integrity and DNA damage were determined. Prior to cryopreservation there was a higher percentage of morphologically normal, motile, P. australis sperm than in those from N. alexis. Following cryopreservation, regardless of treatment, the percentage of motile sperm was low but it was higher when raffinose with skim milk was used as a cryoprotectant than in raffinose with glycerol albeit that minimal differences in membrane integrity or DNA damage were evident. Raffinose with skim milk should thus be used as a cryoprotectant for storing sperm of these Australian rodents in the future.
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6
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McLennan HJ, Lüpold S, Smissen P, Rowe KC, Breed WG. Greater sperm complexity in the Australasian old endemic rodents (Tribe: Hydromyini) is associated with increased levels of inter-male sperm competition. Reprod Fertil Dev 2016; 29:RD15425. [PMID: 26922469 DOI: 10.1071/rd15425] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 01/08/2016] [Indexed: 12/12/2022] Open
Abstract
Spermatozoa exhibit considerable interspecies morphological variation across mammals, especially among murid rodents. In Australasia, most murids in the tribe Hydromyini have a spermatozoon with a highly complex head exhibiting an apical hook, characteristic of most murids, and two projections that extend from its upper concave surface, the ventral processes. In the present study we performed a phylogenetically controlled comparison of sperm morphology across 45 species of hydromyine rodents to test the hypothesis that the length and angle of both the apical hook and ventral processes, as well as the length of the sperm tail, increase with relative testes mass as a proxy for differences in levels of inter-male sperm competition. Although both sperm head protrusions exhibited considerable variation in their length and angle across species, only the angles increased significantly in relation to relative testes mass. Further, the length of the sperm flagellum was positively associated with relative testes mass. These results suggest that, in hydromyine rodents, the angle of the apical hook and ventral processes of the sperm head, as well as the sperm tail length, are likely to be sexually selected traits. The possible functional significance of these findings is briefly discussed.
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7
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Drew S, Leigh C, Breed WG. Spermatozoa of the old endemic rodents of Australia - the possible functional significance of their ventral processes. Reprod Fertil Dev 2013; 26:1183-7. [PMID: 24138753 DOI: 10.1071/rd13162] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2013] [Accepted: 09/13/2013] [Indexed: 11/23/2022] Open
Abstract
Spermatozoa of the plains mouse (Pseudomys australis), like those of most Australian old endemic rodents, contain, in addition to an apical hook, two further processes that extend from the upper concave surface of the head, the ventral processes. This study shows that these processes contain thiol-rich cytoskeletal proteins, which presumably help to maintain their rigidity during sperm transport, together with the overlying cell membrane having abundant intramembranous proteins. To determine the possible functional significance of these processes, an in vitro study of spermatozoon-zona binding was undertaken. The findings suggest that initial sperm binding occurs by way of the cell membrane over the acrosome of the apical hook and that, subsequently, the lateral surfaces of the ventral processes also become tightly bound to the zona matrix. These ventral processes may therefore have evolved to increase sperm adhesion to the outer zona surface and/or to enhance stabilisation of the spermatozoon at the time of zona binding and initial penetration of the egg coat.
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Affiliation(s)
- Simon Drew
- Discipline of Anatomy and Pathology, School of Medical Sciences, Faculty of Heath Sciences, The University of Adelaide, SA 5005, Australia
| | - Chris Leigh
- Discipline of Anatomy and Pathology, School of Medical Sciences, Faculty of Heath Sciences, The University of Adelaide, SA 5005, Australia
| | - William G Breed
- Discipline of Anatomy and Pathology, School of Medical Sciences, Faculty of Heath Sciences, The University of Adelaide, SA 5005, Australia
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8
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Medarde N, Martínez-Vargas J, Sánchez-Chardi A, López-Fuster MJ, Ventura J. Effect of Robertsonian translocations on sperm head form in the house mouse. Biol J Linn Soc Lond 2013. [DOI: 10.1111/bij.12163] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Nuria Medarde
- Departament de Biologia Animal; de Biologia Vegetal i d'Ecologia; Facultat de Biociències; Universitat Autònoma de Barcelona; E-08193 Cerdanyola del Vallès Spain
| | - Jessica Martínez-Vargas
- Departament de Biologia Animal; de Biologia Vegetal i d'Ecologia; Facultat de Biociències; Universitat Autònoma de Barcelona; E-08193 Cerdanyola del Vallès Spain
| | | | - María José López-Fuster
- Departament de Biologia Animal and Institut de Recerca de la Biodiversitat (IRBio); Facultat de Biologia; Universitat de Barcelona; E-08007 Barcelona Spain
| | - Jacint Ventura
- Departament de Biologia Animal; de Biologia Vegetal i d'Ecologia; Facultat de Biociències; Universitat Autònoma de Barcelona; E-08193 Cerdanyola del Vallès Spain
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9
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Breed WG, Tan S, Leigh CM, Aplin KP, Dvorakova-Hortova K, Moore HDM. The morphology of the squirrel spermatozoon: a highly complex male gamete with a massive acrosome. J Morphol 2011; 272:883-9. [PMID: 21547937 DOI: 10.1002/jmor.10955] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2010] [Revised: 01/09/2011] [Accepted: 02/15/2011] [Indexed: 11/05/2022]
Abstract
This study describes the morphology of the spermatozoon from the cauda epididymidis of representative members of two squirrel subfamilies, the Sciurinae and Callosciurinae, as determined by fluorescent, scanning, and transmission electron microscopy. All species examined possess a massive apical segment of the sperm acrosome. It varied markedly in the extent of its caudal flexion but was always much larger, and more complex, than that of the spermatozoon of most other rodents so far documented, although somewhat similar to that of some hystricomorph species. Because this sperm form appears to be present within at least two of the three major living clades of Rodentia, it is possible that it is the ancestral condition within this mammalian order.
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10
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Selvaraj V, Asano A, Page JL, Nelson JL, Kothapalli KSD, Foster JA, Brenna JT, Weiss RS, Travis AJ. Mice lacking FABP9/PERF15 develop sperm head abnormalities but are fertile. Dev Biol 2010; 348:177-89. [PMID: 20920498 DOI: 10.1016/j.ydbio.2010.09.019] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2009] [Revised: 09/22/2010] [Accepted: 09/23/2010] [Indexed: 12/22/2022]
Abstract
The male germ cell-specific fatty acid-binding protein 9 (FABP9/PERF15) is the major component of the murine sperm perforatorium and perinuclear theca. Based on its cytoskeletal association and sequence homology to myelin P2 (FABP8), it has been suggested that FABP9 tethers sperm membranes to the underlying cytoskeleton. Furthermore, its upregulation in apoptotic testicular germ cells and its increased phosphorylation status during capacitation suggested multiple important functions for FABP9. Therefore, we investigated specific functions for FABP9 by means of targeted gene disruption in mice. FABP9(-/-) mice were viable and fertile. Phenotypic analysis showed that FABP9(-/-) mice had significant increases in sperm head abnormalities (~8% greater than their WT cohorts); in particular, we observed the reduction or absence of the characteristic structural element known as the "ventral spur" in ~10% of FABP9(-/-) sperm. However, deficiency of FABP9 affected neither membrane tethering to the perinuclear theca nor the fatty acid composition of sperm. Moreover, epididymal sperm numbers were not affected in FABP9(-/-) mice. Therefore, we conclude that FABP9 plays only a minor role in providing the murine sperm head its characteristic shape and is not absolutely required for spermatogenesis or sperm function.
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Affiliation(s)
- Vimal Selvaraj
- Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.
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11
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Breed WG, Leigh CM. The spermatozoon of the Old Endemic Australo-Papuan and Philippine rodents - its morphological diversity and evolution. ACTA ZOOL-STOCKHOLM 2009. [DOI: 10.1111/j.1463-6395.2009.00407.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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12
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Breed WG, Idriss D, Leigh CM, Oko RJ. Temporal deposition and spatial distribution of cytoskeletal proteins in the sperm head of an Australian rodent. Reprod Fertil Dev 2009; 21:428-39. [PMID: 19261220 DOI: 10.1071/rd08187] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2008] [Accepted: 11/09/2008] [Indexed: 11/23/2022] Open
Abstract
The Australian murine rodent, the plains mouse (Pseudomys australis), possesses a highly complex sperm head, in which there are, in addition to an apical hook, two ventral processes that extend from its upper concave surface. The present study set out to determine the temporal deposition and distribution of the proteins within these structures during late spermiogenesis by light and electron microscopy using various antibodies to bull and laboratory rat sperm-head cytoskeletal proteins. The findings show that there are two phases of protein deposition. In the first phase, perinuclear theca proteins are deposited at the base of the ventral processes around the acrosomal extensions of the developing spermatids. In the second phase, as the ventral processes expand, actin and then perforatorial proteins are laid down during which time the processes become progressively more bilaterally flattened. These various proteins are moulded together to give rise to the two very large cytoskeletal structures that extend from the upper concave surface of the sperm head. They may be involved in binding the spermatozoon to the outer surface of the zona pellucida and/or in aiding the spermatozoon in zona penetration at the time of fertilisation.
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Affiliation(s)
- William G Breed
- Discipline of Anatomical Sciences, School of Medical Sciences, Faculty of Health Sciences, The University of Adelaide, SA 5005, Australia.
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13
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Breed WG, Leigh CM, Robertson H, Mantellato L, Lambert C, Jequier A, Matson P. Interspecific variation of sperm morphology in the Australian rodent genus Zyzomys. ACTA ZOOL-STOCKHOLM 2007. [DOI: 10.1111/j.1463-6395.2007.00277.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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14
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Selvaraj V, Asano A, Buttke DE, McElwee JL, Nelson JL, Wolff CA, Merdiushev T, Fornés MW, Cohen AW, Lisanti MP, Rothblat GH, Kopf GS, Travis AJ. Segregation of micron-scale membrane sub-domains in live murine sperm. J Cell Physiol 2006; 206:636-46. [PMID: 16222699 DOI: 10.1002/jcp.20504] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Lipid rafts, membrane sub-domains enriched in sterols and sphingolipids, are controversial because demonstrations of rafts have often utilized fixed cells. We showed in living sperm that the ganglioside G(M1) localized to a micron-scale membrane sub-domain in the plasma membrane overlying the acrosome. We investigated four models proposed for membrane sub-domain maintenance. G(M1) segregation was maintained in live sperm incubated under non-capacitating conditions, and after sterol efflux, a membrane alteration necessary for capacitation. The complete lack of G(M1) diffusion to the post-acrosomal plasma membrane (PAPM) in live cells argued against the transient confinement zone model. However, within seconds after cessation of sperm motility, G(M1) dramatically redistributed several microns from the acrosomal sub-domain to the post-acrosomal, non-raft sub-domain. This redistribution was not accompanied by movement of sterols, and was induced by the pentameric cholera toxin subunit B (CTB). These data argued against a lipid-lipid interaction model for sub-domain maintenance. Although impossible to rule out a lipid shell model definitively, mice lacking caveolin-1 maintained segregation of both sterols and G(M1), arguing against a role for lipid shells surrounding caveolin-1 in sub-domain maintenance. Scanning electron microscopy of sperm freeze-dried without fixation identified cytoskeletal structures at the sub-domain boundary. Although drugs used to disrupt actin and intermediate filaments had no effect on the segregation of G(M1), we found that disulfide-bonded proteins played a significant role in sub-domain segregation. Together, these data provide an example of membrane sub-domains extreme in terms of size and stability of lipid segregation, and implicate a protein-based membrane compartmentation mechanism.
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Affiliation(s)
- Vimal Selvaraj
- The James A. Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853, USA
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15
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Dvoráková K, Moore HDM, Sebková N, Palecek J. Cytoskeleton localization in the sperm head prior to fertilization. Reproduction 2005; 130:61-9. [PMID: 15985632 DOI: 10.1530/rep.1.00549] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Three major cytoskeletal proteins, actin, tubulin and spectrin, are present in the head of mammalian spermatozoa. Although cytoskeletal proteins are implicated in the regulation of capacitation and the acrosome reaction (AR), their exact role remains poorly understood. The aim of this study was to compare the distribution of the sperm head cytoskeleton before and after the AR in spermatozoa representing a range of acrosome size and shape. Spermatozoa from the human and three rodents (rat, hamster and grey squirrel) were fixed before and after the AR in appropriate medium in vitro. Indirect immunofluorescent localization of cytoskeletal proteins was undertaken with antibodies recognizing actin, spectrin and alpha-tubulin. Preparations were counterstained with propidium iodide and examined by epifluorescent and confocal microscopy. Our results clearly demonstrated changes in localization of cytoskeleton during the AR, mainly in the apical acrosome with further changes to the equatorial segment and post-acrosomal regions. The pattern of cytoskeletal proteins in the sperm head of all the species was similar in respect to various sub-compartments. These observations indicated that the sperm head cortical cytoskeleton exhibits significant changes during the AR and, therefore, support the image of cytoskeletal proteins as highly dynamic structures participating actively in processes prior to fertilization.
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Affiliation(s)
- Katerina Dvoráková
- Department of Developmental Biology, Faculty of Science, Charles University of Prague, Vinicna 7, 12844 Prague 2, Czech Republic
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16
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Abstract
In the rodent superfamily Muroidea, a model for the evolution of sperm form has been proposed in which it is suggested that a hook-shaped sperm head and long tail evolved from a more simple, nonhooked head and short tail in several different subfamilies. To test this model the shape of the sperm head, with particular emphasis on its apical region, and length of sperm tail were matched to a recent phylogeny based on the nucleotide sequence of several protein-coding nuclear genes from 3 families and 10 subfamilies of muroid rodents. Data from the two other myomorph superfamilies, the Dipodoidea and kangaroo rats in the Geomyoidea, were used for an outgroup comparison. In most species in all 10 muroid subfamilies, apart from in the Murinae, the sperm head has a long rostral hook largely composed of acrosomal material, although its length and cross-sectional shape vary across the various subfamilies. Nevertheless, in a few species of various lineages a very different sperm morphology occurs in which an apical hook is lacking. In the outgroups the three species of dipodid rodents have a sperm head that lacks a hook, whereas in the heteromyids an acrosome-containing apical hook is present. It is concluded that, as the hook-shaped sperm head and long sperm tail occur across the muroid subfamilies, as well as in the heteromyid rodents, it is likely to be the ancestral condition within each of the subfamilies with the various forms of nonhooked sperm heads, that are sometimes associated with short tails, being highly derived states. These findings thus argue against a repeated evolution in various muroid lineages of a complex, hook-shaped sperm head and long sperm tail from a more simple, nonhooked sperm head and short tail. An alternative proposal for the evolution of sperm form within the Muroidea is presented in the light of these data.
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Affiliation(s)
- William G Breed
- Department of Anatomical Sciences, The University of Adelaide, SA 5005, Australia.
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17
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Breed WG. The spermatozoon of Eurasian murine rodents: Its morphological diversity and evolution. J Morphol 2004; 261:52-69. [PMID: 15164367 DOI: 10.1002/jmor.10228] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The murine rodents are the most speciose subfamily of mammals. Here the morphology of the spermatozoon, as determined by scanning and transmission electron microscopy of representative species from four Eurasian clades, is described. Much interspecific variability in all components of the spermatozoon was found to occur, although most species have a bilaterally flattened sperm head with a single apical hook of variable length and orientation. Ultrastructural observations indicate that this apical hook invariably contains a nuclear projection as well as a large extension of the subacrosomal cytoskeleton, as a perforatorium rostrally, and a complex asymmetrical acrosomal extension. These spermatozoa also have relatively long tails that are attached to the lower concave surface of the sperm head. Uniquely, in species in the Apodemus clade, the apical hook is orientated caudally. In a few species a highly derived sperm head morphotype that does not contain an apical hook is present. These sperm heads vary in morphology from being globular in two species of Bandicota, to bilaterally flattened and paddle-shaped in Tokudaia and Micromys. In spermatozoa of the latter two genera the subacrosomal cytoskeleton, which is less extensive than in species with a hooked sperm head, forms an apical extension, but that is not the case in Bandicota. In all species where the sperm head lacks an apical hook the acrosome is more symmetrical. The sperm tail is much shorter in these species, with attachment to the head occurring on the ventral surface in Tokudaia and basal in Micromys and the two species of Bandicota. As the sperm head morphotype with a complex apical hook is present in all the major clades of murine rodents, it is likely to be a plesiomorphic character within each of these clades, with the nonhooked sperm heads, which vary greatly in structure between species of the different lineages, probably being independently derived. The ultrastructural organization of the sperm head of Bandicota, but not those of Micromys or Tokudaia, suggest divergence in some of the morphological events associated with sperm-egg interaction at the time of fertilization.
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Affiliation(s)
- William G Breed
- Department of Anatomical Sciences, The University of Adelaide, SA 5005, Australia.
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18
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Tovich PR, Oko RJ. Somatic histones are components of the perinuclear theca in bovine spermatozoa. J Biol Chem 2003; 278:32431-8. [PMID: 12777396 DOI: 10.1074/jbc.m303786200] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The perinuclear theca is a non-ionic detergent-resistant, electron-dense layer surrounding the condensed nucleus of mammalian sperm. The known proteins originating from the perinuclear theca have implicated the structure in a variety of important cellular processes during spermiogenesis and fertilization. Nonetheless, the composition of the perinuclear theca remains largely unexplored. We have isolated a group of low molecular mass (14-19 kDa) perinuclear theca-derived proteins from acrosome-depleted bovine sperm heads by salt (1 M KCl) extraction and have identified them as core somatic histones. N-terminal sequencing and immunoblotting with anti-histone antibodies confirmed the presence of both intact and proteolytically cleaved somatic histones H3, H2B, H2A, and H4. Identical proteins were isolated using 2% SDS or 1 N HCl extractions. Subsequent acid and SDS extractions of intact bovine sperm revealed the presence of all four intact histone subtypes, with minimal proteolysis. Two-dimensional acid/urea/Triton-SDS-PAGE, coupled with immunoblotting analysis, confirmed the somatic nature of these perinuclear theca-derived histones. Estimates of the abundance of perinuclear theca-derived histones showed that up to 0.2 pg per sperm of each histone subtype was present. Immunogold labeling at the ultrastructural level localized all four core somatic histones to the post-acrosomal sheath region of bovine epididymal sperm, when probed with affinity-purified anti-histone antibodies. Little immunoreactivity was detected in residual perinuclear theca structures following the extractions. Taken together, these findings indicate the unprecedented and stable localization of non-nuclear somatic histones in bovine sperm perinuclear theca.
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Affiliation(s)
- P Ronald Tovich
- Department of Anatomy and Cell Biology, Queen's University, Kingston, Ontario K7L 3N6, Canada
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Sutovsky P, Manandhar G, Wu A, Oko R. Interactions of sperm perinuclear theca with the oocyte: implications for oocyte activation, anti-polyspermy defense, and assisted reproduction. Microsc Res Tech 2003; 61:362-78. [PMID: 12811742 DOI: 10.1002/jemt.10350] [Citation(s) in RCA: 113] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Perinuclear theca (PT) is the cytoskeletal coat of mammalian sperm nucleus that is removed from the sperm head at fertilization. PT harbors the sperm borne, oocyte-activating factor (SOAF), a yet-to-be-characterized substance responsible for triggering the signaling cascade of oocyte activation, thought to be dependent on intra-oocyte calcium release. The present article reviews the current knowledge on the biogenesis and molecular composition of sperm PT. Possible functions of sperm PT during natural and assisted fertilization, and in the initiation of embryonic development are discussed. Furthermore, evidence is provided that SOAF is transferred from the sperm PT to oocyte cytoplasm through the internalization and rapid solubilization of the post-acrosomal PT. It is shown that during natural fertilization the sperm PT dissolves in the oocyte cytoplasm concomitantly with sperm nuclear decondensation and the initiation of pronuclear development. SOAF activity is preserved in the differentially extracted sperm heads only if the integrity of PT is maintained. After intracytoplasmic sperm injection (ICSI), activation occurs only in those oocytes in which the injected spermatozoon displays complete or partial dissolution of PT. In the latter case, the residual PT of the sub-acrosomal and/or post-acrosomal sperm region may persist on the apical surface of the sperm nucleus/male pronucleus and may cause a delay or arrest of zygotic development. We propose that the sperm PT harbors SOAF in the post-acrosomal sheath, as this is the first part of the sperm cytosol to enter the oocyte cytoplasm and its disassembly appears sufficient to initiate the early events of oocyte activation. Dissolution of the sub-acrosomal part of the PT, on the other hand, appears necessary to insure complete DNA decondensation in the internalized sperm nucleus and initiate DNA synthesis of both pronuclei. The release of the SOAF from the sperm head into oocyte cytoplasm at fertilization ultimately leads to the activation of oocyte mechanism including the completion of the meiotic cell cycle, pronuclear development and anti-polyspermy defense.
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Affiliation(s)
- Peter Sutovsky
- Department of Animal Sciences, College of Agriculture, Food and Natural Resources, University of Missouri-Columbia, Missouri 65211-5300, USA.
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Abstract
This review considers the role of the sperm in fertilization, addressing areas of misunderstanding and unfounded assumptions and taking particular advantage of the large body of data resulting from work with rodent species in vitro. Considerable attention is given to the appropriate use and interpretation of assays for capacitation, acrosomal exocytosis, hyperactivation, and sperm protein phosphorylation, as well as tests for sperm-zona and sperm-oocyte membrane interactions. The lack of general agreement on the means of sperm adhesion to and penetration of the zona pellucida is addressed, and the need for new approaches to this problem is pointed out. Some molecular advances in our understanding of specific steps in the process of fertilization are discussed in the context of intact cell-matrix and cell-cell interaction. This review should provide practical information for researchers just beginning the study of fertilization and interesting but not widely known observations to stimulate new ideas in experienced scientists.
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Affiliation(s)
- Patricia Olds-Clarke
- Department of Anatomy and Cell Biology, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, USA
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Abstract
The formation and organization of a mammalian sperm head occurs through diverse cellular and molecular processes during spermiogenesis. Such cellular events include sequential changes in the nucleus and the acrosome-which is derived from the Golgi apparatus-in concert with prominent bundles of microtubules, the manchette. However, these complex processes are readily impaired by a variety of intrinsic and extrinsic factors, eventually causing various types of male infertility--such as teratozoospermia--which include the deformation of the acrosome and nucleus. In order to comprehend such idiopathic male infertility syndromes, it is important to clarify the mechanism involved in sperm head formation and organization. In addition to the manchette, two key structures in these events are the acroplaxome and the perinuclear theca. The acroplaxome forms the acrosome plate with periodic intermediate filament bundles of the marginal ring at the leading edge of the acrosome, and its nature has recently been characterized. The perinuclear theca, which is located in the perinuclear region in the sperm head, contains not only a cytoskeletal element to maintain the shape of the sperm head but also functional molecules leading to oocyte activation during fertilization. This review discusses recent developments regarding the formation and organization of the mammalian sperm head in relation to its relevant functions.
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Affiliation(s)
- Kiyotaka Toshimori
- Department of Anatomy and Developmental Biology, Chiba University Graduate School of Medicine, Chiba, Japan.
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Aul RB, Oko RJ. The major subacrosomal occupant of bull spermatozoa is a novel histone H2B variant associated with the forming acrosome during spermiogenesis. Dev Biol 2001; 239:376-87. [PMID: 11784042 DOI: 10.1006/dbio.2001.0427] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Recent studies on the structural composition of mammalian sperm heads have shown a congregate of unidentified proteins occupying the periphery of the mammalian sperm nucleus, forming a layer of condensed cytosol. These proteins are the perinuclear theca (PT) and can be categorized into SDS-soluble and SDS-insoluble components. The present study focused on identifying the major SDS-insoluble PT protein, which we localized to the subacrosomal layer of bovine spermatozoa and cloned by immunoscreening a bull testicular cDNA library. The isolated clones encode a protein of 122 amino acids that bears 67% similarity with histone H2B and contains a predicted histone fold motif. The novel amino terminus of the protein contains a potential bipartite nuclear targeting sequence. Hence, we identified this prominent subacrosomal component as a novel H2B variant, SubH2Bv. Northern blot analyses of SubH2Bv mRNA expression showed that it is testis-specific and is also present in murid testes. Immunocytochemical analysis showed SubH2Bv intimately associates, temporally and spatially, with acrosome formation. While the molecular features of SubH2Bv are common to nuclear proteins, it is never seen developmentally within the nucleus of the spermatid. Considering its developmental and molecular characteristics, we have postulated roles of SubH2Bv in acrosome assembly and acrosome-nuclear docking.
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Affiliation(s)
- R B Aul
- Department of Anatomy and Cell Biology, Queen's University, Kingston, Ontario, Canada, K7L 3N6
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