scholarly journals TMEM95 is a sperm membrane protein essential for mammalian fertilization

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Ismael Lamas-Toranzo ◽  
Julieta G Hamze ◽  
Enrica Bianchi ◽  
Beatriz Fernández-Fuertes ◽  
Serafín Pérez-Cerezales ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Membrane Fusion ◽  
Zona Pellucida ◽  
Sperm Protein ◽  
Egg Protein ◽  
Egg Membrane ◽  
Sperm Membrane ◽  
Mammalian Fertilization ◽  
Male Specific ◽  
Mechanical Injection

The fusion of gamete membranes during fertilization is an essential process for sexual reproduction. Despite its importance, only three proteins are known to be indispensable for sperm-egg membrane fusion: the sperm proteins IZUMO1 and SPACA6, and the egg protein JUNO. Here we demonstrate that another sperm protein, TMEM95, is necessary for sperm-egg interaction. TMEM95 ablation in mice caused complete male-specific infertility. Sperm lacking this protein were morphologically normal exhibited normal motility, and could penetrate the zona pellucida and bind to the oolemma. However, once bound to the oolemma, TMEM95-deficient sperm were unable to fuse with the egg membrane or penetrate into the ooplasm, and fertilization could only be achieved by mechanical injection of one sperm into the ooplasm, thereby bypassing membrane fusion. These data demonstrate that TMEM95 is essential for mammalian fertilization.

scholarly journals The sperm protein Spaca6 is essential for fertilization in zebrafish

2021 ◽  
Author(s):  
Mirjam Isabel Binner ◽  
Anna Kogan ◽  
Karin Panser ◽  
Alexander Schleiffer ◽  
Victoria Eugenia Deneke ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Molecular Mechanisms ◽  
Membrane Binding ◽  
Normal Morphology ◽  
Sperm Protein ◽  
Fertility Factor ◽  
Egg Membrane ◽  
Sperm Factor ◽  
Sperm Membrane

Fertilization is a key process in all sexually reproducing species, yet the molecular mechanisms that underlie this event remain unclear. To date, only a few proteins have been shown to be essential for sperm-egg binding and fusion in mice, and only some are conserved across vertebrates. One of these conserved, testis-expressed factors is SPACA6, yet its function has not been investigated outside of mammals. Here we show that zebrafish spaca6 encodes for a sperm membrane protein which is essential for fertilization. Zebrafish spaca6 knockout males are sterile. Furthermore, Spaca6-deficient sperm have normal morphology, are motile, and can approach the egg, but fail to bind to the egg and therefore cannot complete fertilization. Interestingly, sperm lacking Spaca6 have decreased levels of another essential and conserved sperm fertility factor, Dcst2, revealing a previously unknown dependence of Dcst2 expression on Spaca6. Together, our results show that zebrafish Spaca6 regulates Dcst2 levels and is required for binding between the sperm membrane and the oolemma. This is in contrast to murine SPACA6, which was reported not to be required for sperm-egg membrane binding but necessary for fusion. These findings demonstrate that Spaca6 is essential for zebrafish fertilization and is a conserved sperm factor in vertebrate reproduction.

scholarly journals The sperm protein SPACA4 is required for efficient fertilization in mice

2021 ◽  
Author(s):  
Sarah Herberg ◽  
Yoshitaka Fujihara ◽  
Andreas Blaha ◽  
Karin Panser ◽  
Kiyonari Kobayashi ◽  
...  
Keyword(s):  
Zona Pellucida ◽  
Knockout Mice ◽  
Mammalian Species ◽  
Wild Type ◽  
Sperm Protein ◽  
Mammalian Sperm ◽  
Fundamental Process ◽  
Mammalian Fertilization

Fertilization is the fundamental process that initiates the development of a new individual in all sexually reproducing species. Despite its importance, our understanding of the molecular players that govern mammalian sperm-egg interaction is incomplete, partly because many of the essential factors found in non-mammalian species do not have obvious mammalian homologs. We have recently identified the Ly6/uPAR protein Bouncer as a new, essential fertilization factor in zebrafish (Herberg et al., 2018). Here, we show that Bouncer's homolog in mammals, SPACA4, is also required for efficient fertilization in mice. In contrast to fish, where Bouncer is expressed specifically in the egg, SPACA4 is expressed exclusively in the testis. Male knockout mice are severely sub-fertile, and sperm lacking SPACA4 fail to fertilize wild-type eggs in vitro. Interestingly, removal of the zona pellucida rescues the fertilization defect of Spaca4-deficient sperm in vitro, indicating that SPACA4 is not required for the interaction of sperm and the oolemma but rather of sperm and zona pellucida. Our work identifies SPACA4 as an important sperm protein necessary for zona pellucida penetration during mammalian fertilization.

scholarly journals Inhibition of mouse acrosome reaction and sperm-zona pellucida binding by anti-human sperm membrane protein 1 antibody

2007 ◽  
Vol 9 (1) ◽  
pp. 23-29 ◽  
Author(s):  
Guo-Yan Cheng ◽  
Jian-Li Shi ◽  
Min Wang ◽  
Yan-Qin Hu ◽  
Chun-Meng Liu ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Zona Pellucida ◽  
Acrosome Reaction ◽  
Human Sperm ◽  
Sperm Membrane

scholarly journals ZP3-dependent activation of sperm cation channels regulates acrosomal secretion during mammalian fertilization.

1996 ◽  
Vol 134 (3) ◽  
pp. 637-645 ◽  
Author(s):  
C Arnoult ◽  
Y Zeng ◽  
H M Florman
Keyword(s):  
Membrane Potential ◽  
Pertussis Toxin ◽  
Zona Pellucida ◽  
Mammalian Sperm ◽  
Transient Rise ◽  
Transduction Mechanisms ◽  
Dependent Signal ◽  
Sperm Membrane ◽  
Mammalian Fertilization

The sperm acrosome reaction is a Ca(2+)-dependent secretory event required for fertilization. Adhesion to the egg's zona pellucida promotes Ca2+ influx through voltage-sensitive channels, thereby initiating secretion. We used potentiometric fluorescent probes to determine the role of sperm membrane potential in regulating Ca2+ entry. ZP3, the glycoprotein agonist of the zona pellucida, depolarizes sperm membranes by activating a pertussis toxin-insensitive mechanism with the characteristics of a poorly selective cation channel. ZP3 also activates a pertussis toxin-sensitive pathway that produces a transient rise in internal pH. The concerted effects of depolarization and alkalinization open voltage-sensitive Ca2+ channels. These observations suggest that mammalian sperm utilize membrane potential-dependent signal transduction mechanisms and that a depolarization pathway is an upstream transducing element coupling adhesion to secretion during fertilization.

scholarly journals Author response: TMEM95 is a sperm membrane protein essential for mammalian fertilization

2020 ◽  
Author(s):  
Ismael Lamas-Toranzo ◽  
Julieta G Hamze ◽  
Enrica Bianchi ◽  
Beatriz Fernández-Fuertes ◽  
Serafín Pérez-Cerezales ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Author Response ◽  
Sperm Membrane ◽  
Mammalian Fertilization

scholarly journals The conserved fertility factor SPACA4/Bouncer has divergent modes of action in vertebrate fertilization

2021 ◽  
Vol 118 (39) ◽  
pp. e2108777118
Author(s):  
Yoshitaka Fujihara ◽  
Sarah Herberg ◽  
Andreas Blaha ◽  
Karin Panser ◽  
Kiyonori Kobayashi ◽  
...  
Keyword(s):  
Zona Pellucida ◽  
Wild Type ◽  
Sperm Protein ◽  
Mammalian Sperm ◽  
Type Plasminogen Activator ◽  
Urokinase Type Plasminogen Activator ◽  
Fundamental Process ◽  
Mammalian Fertilization ◽  
Plasminogen Activator Receptor

Fertilization is the fundamental process that initiates the development of a new individual in all sexually reproducing species. Despite its importance, our understanding of the molecular players that govern mammalian sperm–egg interaction is incomplete, partly because many of the essential factors found in nonmammalian species do not have obvious mammalian homologs. We have recently identified the lymphocyte antigen-6 (Ly6)/urokinase-type plasminogen activator receptor (uPAR) protein Bouncer as an essential fertilization factor in zebrafish [S. Herberg, K. R. Gert, A. Schleiffer, A. Pauli, Science 361, 1029–1033 (2018)]. Here, we show that Bouncer’s homolog in mammals, Sperm Acrosome Associated 4 (SPACA4), is also required for efficient fertilization in mice. In contrast to fish, in which Bouncer is expressed specifically in the egg, SPACA4 is expressed exclusively in the sperm. Male knockout mice are severely subfertile, and sperm lacking SPACA4 fail to fertilize wild-type eggs in vitro. Interestingly, removal of the zona pellucida rescues the fertilization defect of Spaca4-deficient sperm in vitro, indicating that SPACA4 is not required for the interaction of sperm and the oolemma but rather of sperm and the zona pellucida. Our work identifies SPACA4 as an important sperm protein necessary for zona pellucida penetration during mammalian fertilization.

scholarly journals The Sperm Protein Spaca6 is Essential for Fertilization in Zebrafish

2022 ◽  
Vol 9 ◽  
Author(s):  
Mirjam I. Binner ◽  
Anna Kogan ◽  
Karin Panser ◽  
Alexander Schleiffer ◽  
Victoria E. Deneke ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Molecular Mechanisms ◽  
Normal Morphology ◽  
Sperm Protein ◽  
Fertility Factor ◽  
Sperm Factor ◽  
Sperm Membrane

Fertilization is a key process in all sexually reproducing species, yet the molecular mechanisms that underlie this event remain unclear. To date, only a few proteins have been shown to be essential for sperm-egg binding and fusion in mice, and only some are conserved across vertebrates. One of these conserved, testis-expressed factors is SPACA6, yet its function has not been investigated outside of mammals. Here we show that zebrafish spaca6 encodes for a sperm membrane protein which is essential for fertilization. Zebrafish spaca6 knockout males are sterile. Furthermore, Spaca6-deficient sperm have normal morphology, are motile, and can approach the egg, but fail to bind to the egg and therefore cannot complete fertilization. Interestingly, sperm lacking Spaca6 have decreased levels of another essential and conserved sperm fertility factor, Dcst2, revealing a previously unknown dependence of Dcst2 expression on Spaca6. Together, our results show that zebrafish Spaca6 regulates Dcst2 levels and is required for binding between the sperm membrane and the oolemma. This is in contrast to murine sperm lacking SPACA6, which was reported to be able to bind but unable to fuse with oocytes. These findings demonstrate that Spaca6 is essential for zebrafish fertilization and is a conserved sperm factor in vertebrate reproduction.

scholarly journals Sperm proteins SOF1, TMEM95, and SPACA6 are required for sperm−oocyte fusion in mice

2020 ◽  
Vol 117 (21) ◽  
pp. 11493-11502 ◽  
Author(s):  
Taichi Noda ◽  
Yonggang Lu ◽  
Yoshitaka Fujihara ◽  
Seiya Oura ◽  
Takayuki Koyano ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Membrane Protein ◽  
Transgenic Mice ◽  
Membrane Fusion ◽  
Molecular Mechanisms ◽  
Cultured Cells ◽  
Transmembrane Protein ◽  
Sperm Proteins ◽  
Sperm Membrane ◽  
Oocyte Membrane

Sperm−oocyte membrane fusion is one of the most important events for fertilization. So far, IZUMO1 and Fertilization Influencing Membrane Protein (FIMP) on the sperm membrane and CD9 and JUNO (IZUMO1R/FOLR4) on the oocyte membrane have been identified as fusion-required proteins. However, the molecular mechanisms for sperm−oocyte fusion are still unclear. Here, we show that testis-enriched genes, sperm−oocyte fusion required 1 (Sof1/Llcfc1/1700034O15Rik), transmembrane protein 95 (Tmem95), and sperm acrosome associated 6 (Spaca6), encode sperm proteins required for sperm−oocyte fusion in mice. These knockout (KO) spermatozoa carry IZUMO1 but cannot fuse with the oocyte plasma membrane, leading to male sterility. Transgenic mice which expressed mouseSof1,Tmem95,andSpaca6rescued the sterility ofSof1,Tmem95, andSpaca6KO males, respectively. SOF1 and SPACA6 remain in acrosome-reacted spermatozoa, and SPACA6 translocates to the equatorial segment of these spermatozoa. The coexpression of SOF1, TMEM95, and SPACA6 in IZUMO1-expressing cultured cells did not enhance their ability to adhere to the oocyte membrane or allow them to fuse with oocytes. SOF1, TMEM95, and SPACA6 may function cooperatively with IZUMO1 and/or unknown fusogens in sperm−oocyte fusion.

scholarly journals Spermatozoa lacking Fertilization Influencing Membrane Protein (FIMP) fail to fuse with oocytes in mice

2020 ◽  
Vol 117 (17) ◽  
pp. 9393-9400 ◽  
Author(s):  
Yoshitaka Fujihara ◽  
Yonggang Lu ◽  
Taichi Noda ◽  
Asami Oji ◽  
Tamara Larasati ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Transmembrane Protein ◽  
Critical Role ◽  
Fusion Process ◽  
Critical Event ◽  
Specific Gene ◽  
Fusion Event ◽  
Sperm Membrane ◽  
Mammalian Fertilization ◽  
Oocyte Membrane

Sperm–oocyte fusion is a critical event in mammalian fertilization, categorized by three indispensable proteins. Sperm membrane protein IZUMO1 and its counterpart oocyte membrane protein JUNO make a protein complex allowing sperm to interact with the oocyte, and subsequent sperm–oocyte fusion. Oocyte tetraspanin protein CD9 also contributes to sperm–oocyte fusion. However, the fusion process cannot be explained solely by these three essential factors. In this study, we focused on analyzing a testis-specific gene 4930451I11Rik and generated mutant mice using the CRISPR/Cas9 system. Although IZUMO1 remained in 4930451I11Rik knockout (KO) spermatozoa, the KO spermatozoa were unable to fuse with oocytes and the KO males were severely subfertile. 4930451I11Rik encodes two isoforms: a transmembrane (TM) form and a secreted form. Both CRISPR/Cas9-mediated TM deletion and transgenic (Tg) rescue with the TM form revealed that only the TM form plays a critical role in sperm–oocyte fusion. Thus, we renamed this TM form Fertilization Influencing Membrane Protein (FIMP). The mCherry-tagged FIMP TM form was localized to the sperm equatorial segment where the sperm–oocyte fusion event occurs. Thus, FIMP is a sperm-specific transmembrane protein that is necessary for the sperm–oocyte fusion process.

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