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Faure JE, Myles DG, Primakoff P. The frequency of calcium oscillations in mouse eggs at fertilization is modulated by the number of fused sperm. Dev Biol 1999; 213:370-7. [PMID: 10479454 DOI: 10.1006/dbio.1999.9388] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In a variety of calcium signaling systems, the frequency of intracellular calcium oscillations is physiologically important. Probably multiple factors control the frequency of calcium oscillations in the egg after fertilization and many of these remain to be identified. In this study, we present the first rigorous set of data showing that monospermic fertilization is important for setting the physiological calcium oscillation frequency. Recordings in 152 zona-free eggs show that the general pattern of the calcium oscillations is identical in monospermic and polyspermic eggs; however, the oscillation frequency is higher in polyspermic eggs (P < 10(-6)). The frequency of the late oscillations increases with the number of sperm heads incorporated: 5.2 +/- 0.3 spikes per hour (mean +/- SEM; n = 55) in monospermic eggs, 6.6 +/- 0.3 (n = 62) in dispermic eggs, 8.7 +/- 0.7 (n = 23) in trispermic eggs, and 8.9 +/- 0.9 (n = 12) in eggs with four or more sperm heads. The frequency of the early oscillations is also increased in polyspermic eggs. Seventy-eight additional eggs were divided into two groups and inseminated with two different sperm concentrations ("low" and "high") to obtain one group mainly monospermic and the other mainly polyspermic. The two groups of eggs oscillated at different frequencies (P < 10(-5)). These data rule out the possibility of an egg effect in which some eggs would have the dual properties of oscillating faster and of being able to fuse with several sperm cells. These data instead suggest that the sperm modulates the frequency of the oscillations in a dose-dependent manner.
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Zhu GZ, Lin Y, Myles DG, Primakoff P. Identification of four novel ADAMs with potential roles in spermatogenesis and fertilization. Gene 1999; 234:227-37. [PMID: 10395895 DOI: 10.1016/s0378-1119(99)00208-5] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The ADAM (A Disintegrin And Metalloprotease) family is known to have important roles in various developmental systems, e.g., myogenesis and neurogenesis. In this study, we searched for ADAMs that may function in spermatogenesis or fertilization, and have cloned and sequenced four new mouse ADAM cDNAs: ADAM 24, ADAM 25, ADAM 26 and ADAM 27. The deduced amino acid sequences show that all four contain the complete domain organization common to ADAM family members. Messenger RNA for each of the four ADAMs was found only in the testis. The conserved zinc-dependent metalloprotease active site HEXGHXXGXXHD was found in the metalloprotease domain of three of the novel ADAMs, suggesting that they are testis-specific proteases, to which we give the alternative names: testase 1, ADAM 24; testase 2, ADAM 25; and testase 3, ADAM 26. Using RNA extracted from testes of pre-pubertal males of increasing age (8-40days), we found that adult levels of transcription, assessed in Northern blots, are reached by day 20 (ADAM 27), day 25 (ADAMs 24 and 25) and in the range day 25-50 (ADAM 26). These results suggest that each ADAM is transcribed in spermatogenic cells in a regulated pattern at a specific developmental stage.
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Cho C, Bunch DO, Faure JE, Goulding EH, Eddy EM, Primakoff P, Myles DG. Fertilization defects in sperm from mice lacking fertilin beta. Science 1998; 281:1857-9. [PMID: 9743500 DOI: 10.1126/science.281.5384.1857] [Citation(s) in RCA: 408] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Fertilin, a member of the ADAM family, is found on the plasma membrane of mammalian sperm. Sperm from mice lacking fertilin beta were shown to be deficient in sperm-egg membrane adhesion, sperm-egg fusion, migration from the uterus into the oviduct, and binding to the egg zona pellucida. Egg activation was unaffected. The results are consistent with a direct role of fertilin in sperm-egg plasma membrane interaction. Fertilin could also have a direct role in sperm-zona binding or oviduct migration; alternatively, the effects on these functions could result from the absence of fertilin activity during spermatogenesis.
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Li MW, Yudin AI, VandeVoort CA, Sabeur K, Primakoff P, Overstreet JW. Inhibition of monkey sperm hyaluronidase activity and heterologous cumulus penetration by flavonoids. Biol Reprod 1997; 56:1383-9. [PMID: 9166689 DOI: 10.1095/biolreprod56.6.1383] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
A microplate assay for hyaluronidase and a heterologous cumulus penetration assay were used to determine the effects of four flavonoids (tannic acid, kaempferol, quercetin, and apigenin) on the function of cynomolgus monkey sperm. All four flavonoids inhibited the activity of hyaluronidase extracted from monkey sperm in a concentration-dependent manner over the range of 50-200 microM. Tannic acid and apigenin had lower inhibitory effects than kaempferol and quercetin. Kaempferol, quercetin, and apigenin at 100 microM were shown to significantly inhibit monkey sperm penetration into hamster cumulus. There was a significant linear relationship between the capacity of the flavonoids to inhibit monkey sperm hyaluronidase activity and their inhibitory effects on hamster cumulus penetration (r = 0.97). Tannic acid was observed to reduce sperm motility, and it was not used in the cumulus penetration assay. The other three flavonoids tested in the cumulus penetration assay did not affect sperm motility, nor did they induce acrosome reactions. The results demonstrate that the flavonoids are useful tools for assessing the involvement of hyaluronidase in the functions of monkey sperm that are involved in fertilization.
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Primakoff P, Woolman-Gamer L, Tung KS, Myles DG. Reversible contraceptive effect of PH-20 immunization in male guinea pigs. Biol Reprod 1997; 56:1142-6. [PMID: 9160712 DOI: 10.1095/biolreprod56.5.1142] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Sperm proteins are currently being studied as antigens on which to base a contraceptive vaccine. Sperm plasma membrane proteins offer the theoretical possibility of immunizing either males or females and achieving a contraceptive effect. In this study, we investigated the sperm plasma membrane protein PH-20 as an antigen for inducing infertility in males. We found that infertility can reproducibly be induced in male guinea pigs immunized with purified PH-20: 100% (29 of 29) of PH-20-immunized males became infertile, whereas all 22 controls were fertile. The males were extremely responsive to PH-20 immunization: infertility could be induced with a single injection of only 5 microg PH-20. Among males that received their initial injection when they were approximately 300 g (body weight), 14 of 15 had regained fertility at about 1 yr after initial injection. Surprisingly, in another group of males that received their first injection when they were approximately 650 g (body weight), only 1 of 5 had regained fertility about 1 yr after initial injection. Anti-PH-20 titers in antisera (2 mo after initial injection) were generally in the range 1.1-4.2 x 10(4) in twice-injected males and the range 1.8-9.4 x 10(3) in once-injected males. Over the next 6-11 mo, twice-injected males' titers decreased > or = 4-fold, whereas once-injected males' titers decreased slightly (1.1 - to 1.8-fold). After 6-11 mo, anti-PH-20 titers were in the range 1.0-4.8 x 10(3), and the precise residual titer did not correlate with fertility/infertility. The results show that immunization of males with PH-20, even at low doses, results in a reproducible, completely effective contraceptive action.
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Tung KS, Primakoff P, Woolman-Gamer L, Myles DG. Mechanism of infertility in male guinea pigs immunized with sperm PH-20. Biol Reprod 1997; 56:1133-41. [PMID: 9160711 DOI: 10.1095/biolreprod56.5.1133] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
PH-20, a testis-specific protein first expressed in haploid germ cells, is present on the posterior head plasma membrane and inner acrosomal membrane of mature guinea pig sperm. PH-20 is bifunctional, having a hyaluronidase activity that allows sperm to penetrate the cumulus layer and a separate activity required for binding of acrosome-reacted sperm to the zona pellucida. The immunization of male guinea pigs with PH-20 reproducibly results in infertility with a duration of 6-12 mo or longer. In this study, we analyzed the immunopathology in the reproductive tract of PH-20-immunized males to probe the mechanism(s) responsible for the induced infertility and found two separate effects. Remarkably, in almost all infertile, PH-20-immunized males, the caudae epididymides were empty (contained no sperm) or contained only abnormal sperm. The complete loss of normal sperm in the epididymis apparently results in infertility. A second effect was the induction of experimental autoimmune orchitis (EAO), representing the first report of EAO induced by a purified testis/sperm molecule of known functions. PH-20-induced EAO differed from EAO induced by crude testis antigens in two respects: 1) an absence of epididymitis with abscess and granuloma and 2) the presence of antibody on germ cells within seminiferous tubules and inside the cauda epididymidis. The former suggests that crude testis antigens other than PH-20 are responsible for epididymitis, and the latter suggests a possible role of antibody in EAO pathogenesis and infertility induction. Return to fertility, after 6-12 mo, was accompanied by regression of EAO and reappearance of spermatozoa in the caudae epididymides.
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Yuan R, Primakoff P, Myles DG. A role for the disintegrin domain of cyritestin, a sperm surface protein belonging to the ADAM family, in mouse sperm-egg plasma membrane adhesion and fusion. J Cell Biol 1997; 137:105-12. [PMID: 9105040 PMCID: PMC2139869 DOI: 10.1083/jcb.137.1.105] [Citation(s) in RCA: 183] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/1996] [Revised: 01/20/1997] [Indexed: 02/04/2023] Open
Abstract
Sperm-egg plasma membrane fusion is preceded by sperm adhesion to the egg plasma membrane. Cell-cell adhesion frequently involves multiple adhesion molecules on the adhering cells. One sperm surface protein with a role in sperm-egg plasma membrane adhesion is fertilin, a transmembrane heterodimer (alpha and beta subunits). Fertilin alpha and beta are the first identified members of a new family of membrane proteins that each has the following domains: pro-, metalloprotease, disintegrin, cysteine-rich, EGF-like, transmembrane, and cytoplasmic domain. This protein family has been named ADAM because all members contain a disintegrin and metalloprotease domain. Previous studies indicate that the disintegrin domain of fertilin beta functions in sperm-egg adhesion leading to fusion. Full length cDNA clones have been isolated for five ADAMs expressed in mouse testis: fertilin alpha, fertilin beta, cyritestin, ADAM 4, and ADAM 5. The presence of the disintegrin domain, a known integrin ligand, suggests that like fertilin beta, other testis ADAMs could be involved in sperm adhesion to the egg membrane. We tested peptide mimetics from the predicted binding sites in the disintegrin domains of the five testis-expressed ADAMs in a sperm-egg plasma membrane adhesion and fusion assay. The active site peptide from cyritestin strongly inhibited (80-90%) sperm adhesion and fusion and was a more potent inhibitor than the fertilin beta active site peptide. Antibodies generated against the active site region of either cyritestin or fertilin beta also strongly inhibited (80-90%) both sperm-egg adhesion and fusion. Characterization of these two ADAM family members showed that they are both processed during sperm maturation and present on mature sperm. Indirect immunofluorescence on live, acrosome-reacted sperm using antibodies against either cyritestin or fertilin beta showed staining of the equatorial region, a region of the sperm membrane that participates in the early steps of membrane fusion. Collectively, these data indicate that a second ADAM family member, cyritestin, functions with fertilin beta in sperm-egg plasma membrane adhesion leading to fusion.
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Pyluck A, Yuan R, Galligan E, Primakoff P, Myles DG, Sampson NS. ECD peptides inhibit in vitro fertilization in mice. Bioorg Med Chem Lett 1997. [DOI: 10.1016/s0960-894x(97)00160-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Meyers SA, Yudin AI, Cherr GN, VandeVoort CA, Myles DG, Primakoff P, Overstreet JW. Hyaluronidase activity of macaque sperm assessed by an in vitro cumulus penetration assay. Mol Reprod Dev 1997; 46:392-400. [PMID: 9041143 DOI: 10.1002/(sici)1098-2795(199703)46:3<392::aid-mrd19>3.0.co;2-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
A model system consisting of cynomolgus macaque sperm and ovulated hamster ova-cumulus complexes (OCCs) was utilized to study the role of the sperm protein PH-20 in cumulus penetration. The hyaluronidase activity of solubilized macaque sperm PH-20 was evaluated using an ELISA-like microplate assay prior to and following the addition of the hyaluronidase inhibitors heparin (0-100 microg/ml) and apigenin (250 microM), as well as the Ig fraction of a polyclonal antibody raised against purified recombinant macaque PH-20 (R10; 10-400 microg/ml). Sperm motility following exposure to enzyme inhibitors was evaluated using computer-aided sperm motility analysis. Macaque sperm were labeled with the permeant fluorescent nuclear dye, Hoechst 33342, and were coincubated with ovulated hamster OCCs for 30 min at 37 degrees C. The addition of heparin, apigenin, or R10 antibody to solubilized sperm extracts resulted in a linear dose-dependent decrease in hyaluronidase activity (P < .01). In the heterologous cumulus penetration assay, fluorescently labeled macaque sperm that were pretreated with heparin (1-100 microg/ml), apigenin (250 microM), or R10 antibody (Ig fraction, 10-400 microg/ml) demonstrated a dose-dependent decrease in the ability to penetrate hamster OCCs (P < 0.01), in the absence of effects on sperm motility. In the homologous assay, experiments using macaque OCCs and fluorescently labeled macaque sperm confirmed that the same concentrations of heparin and R10 antibody similarly suppressed spermatozoal cumulus penetration (P < .01). These results suggest that macaque sperm PH-20-derived hyaluronidase participates in cumulus penetration in this species, and that this model system is useful for further studies into primate gamete interaction.
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Sabeur K, Cherr GN, Yudin AI, Primakoff P, Li MW, Overstreet JW. The PH-20 protein in human spermatozoa. JOURNAL OF ANDROLOGY 1997; 18:151-8. [PMID: 9154509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
PH-20 is a sperm plasma-membrane protein that has been shown to have hyaluronidase activity in several mammalian species including nonhuman primates. In this investigation, the PH-20 protein was characterized in noncapacitated human sperm and in capacitated human sperm. Two forms of PH-20 were observed in immunoblots of sodium dodecylsulfate polyacrylamide-gel electrophoresis (SDS PAGE) using a polyclonal antibody to recombinant PH-20: a major band of 64 kDa appeared in noncapacitated and capacitated sperm extracts and a 53-kDa band that appeared only in the acrosome-reaction supernatant of acrosome-reacted sperm. Using hyaluronic acid substrate gel analysis, we demonstrated that noncapacitated sperm extracts, capacitated sperm extracts, and the acrosome-reaction supernatant had hyaluronidase activity at neutral pH (pH 7) and acid pH (pH 4). The 64-kDa form in all samples had hyaluronidase activity at both neutral and acid pH, but the 53-kDa form was only active at acid pH. Total hyaluronidase activity, as measured by a microplate assay, was higher at pH 7 than at pH 4. Very low hyaluronidase activity was detected in the acrosome-reaction supernatant. Transmission electron microscopy and immunogold labeling showed that PH-20 of acrosome-intact human sperm was located on the plasma membrane over the entire head but not on the sperm midpiece and tail. After the acrosome reaction, PH-20 was also located on the inner acrosomal membrane. The biochemical characteristics and the ultrastructural localization of PH-20 in human sperm suggest that this protein is the human sperm hyaluronidase and, therefore, has an important function during fertilization.
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Myles DG, Primakoff P. Why did the sperm cross the cumulus? To get to the oocyte. Functions of the sperm surface proteins PH-20 and fertilin in arriving at, and fusing with, the egg. Biol Reprod 1997; 56:320-7. [PMID: 9116127 DOI: 10.1095/biolreprod56.2.320] [Citation(s) in RCA: 124] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The sperm surface has an active role in the events of fertilization. The definition of the sperm surface in both its composition and domain organization begins during spermatogenesis and continues until the moment of sperm-egg fusion. Alterations of the surface proceed as a result of internal programming and environmental cues from both the male and female reproductive tracts, including interactions with the egg itself. We have investigated the sperm surface to understand its domain organization and the ongoing changes in this organization as well as the role of specific surface proteins in fertilization. Much of our research has concentrated on two surface proteins: PH-20 and fertilin. PH-20 is a single-chain protein, anchored in the membrane via a glycosyl phosphatidylinositol (GPI) anchor. The N-terminal domain of the molecule has a hyaluronidase activity. The hyaluronidase activity of PH-20 on the sperm plasma membrane enables sperm to penetrate the layer of cumulus cells surrounding the oocyte. PH-20 has a second function, unrelated to its hyaluronidase activity, in the binding of acrosome-reacted sperm to the zona pellucida (secondary sperm-zona binding). The fertilin molecule is an alpha,beta heterodimer whose two subunits are closely related transmembrane proteins. Fertilin beta has a disintegrin domain that has high sequence homology with the snake disintegrins, a known class of soluble integrin ligands. The binding site of the beta disintegrin domain functions to bind sperm to the egg plasma membrane via a mechanism that leads to sperm-egg fusion. The precursor of fertilin alpha, made in the testis, has an active metalloprotease site that could function in spermatogenesis. This metalloprotease domain is removed by proteolytic processing in the testis. Mature fertilin alpha on sperm also has a hydrophobic, putative "fusion peptide" that may promote the process of lipid bilayer fusion between sperm and egg plasma membranes. Fertilin alpha and beta are the first identified members of a new gene family of transmembrane proteins, the ADAM family, so called because they contain A Disintegrin And Metalloprotease domain. Many distinct ADAMs have now been found in diverse tissues and species (Drosophila to human) and are proposed to have a variety of functions in development and the adult. In addition to fertilin, other ADAMs are also present on the sperm plasma membrane and may participate with fertilin in sperm-egg fusion.
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Deng X, Moran J, Copeland NG, Gilbert DJ, Jenkins NA, Primakoff P, Martin-DeLeon PA. The mouse Spam1 maps to proximal chromosome 6 and is a candidate for the sperm dysfunction in Rb(6.16)24Lub and Rb(6.15)1Ald heterozygotes. Mamm Genome 1997; 8:94-7. [PMID: 9060406 DOI: 10.1007/s003359900365] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We have determined the chromosomal localization of the murine gene encoding the 68-kDa sperm adhesion molecule 1, Spam1 or Ph-20. Using two independent approaches, fluorescence in situ hybridization (FISH) and interspecific backcross analysis we show the Spam1 maps to proximal mouse Chromosome (Chr) 6. This map position is within the conserved linkage group corresponding to human Chr 7q, where the human homolog, SPAM 1, has been shown to map previously. Genetic mapping shows the gene to be very closely linked to Met, one of the most proximal loci on MMU 6. It thus places the gene near the centromere and the junction of the Rb(6.16)24Lub and Rb(6.15)1Ald translocations. The essential role of the Spam1 sperm antigen in mouse sperm-egg interactions and its gene location provide strong support for its candidacy as the gene involved in the dysfunction of mouse sperm bearing the Rb(6.16)24Lub or Rb(6.15)1Ald translocation.
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Hunnicutt GR, Primakoff P, Myles DG. Sperm surface protein PH-20 is bifunctional: one activity is a hyaluronidase and a second, distinct activity is required in secondary sperm-zona binding. Biol Reprod 1996; 55:80-6. [PMID: 8793062 DOI: 10.1095/biolreprod55.1.80] [Citation(s) in RCA: 107] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
In previous studies, we have found that the sperm membrane protein PH-20 acts during two different stages of fertilization. On acrosome-intact sperm, PH-20 has a hyaluronidase activity that is required for sperm penetration through the cumulus cell layer that surrounds the oocyte. On acrosome-reacted sperm, PH-20 has a required function in sperm-zona binding (secondary binding). Because hyaluronic acid (HA) has been detected in the zona pellucida, secondary sperm-zona adhesion could depend on repetitive binding and hydrolysis of HA by PH-20 acting as a hyaluronidase. Alternatively, PH-20 may be bifunctional and have a second, different activity required for secondary binding. To distinguish between these two possibilities, in this study we used reagents that inhibit either PH-20's function in sperm-zona binding or its hyaluronidase activity. We found that an anti-PH-20 monoclonal antibody that inhibited sperm-zona binding (approximately 90%) had no effect on hyaluronidase activity. Conversely, apigenin, a hyaluronidase inhibitor, blocked PH-20 hyaluronidase activity 93% without inhibiting sperm-zona binding. Similarly, another anti-PH-20 monoclonal antibody that inhibited hyaluronidase activity 95% only partially inhibited sperm-zona binding (approximately 45%). We also extensively pretreated oocytes with hyaluronidase to remove all accessible HA on or in the zona pellucida and found little or no effect on secondary sperm-zona binding. Our results suggest that PH-20 is bifunctional and has two activities: a hyaluronidase activity and a second, separate activity required for secondary sperm-zona binding.
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Cho C, Primakoff P, White JM, Myles DG. Chromosomal assignment of four testis-expressed mouse genes from a new family of transmembrane proteins (ADAMs) involved in cell-cell adhesion and fusion. Genomics 1996; 34:413-7. [PMID: 8786143 DOI: 10.1006/geno.1996.0305] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
A new gene family of multidomain membrane proteins (ADAMs) that include A Disintegrin And Metalloprotease domain comprises an increasing number of identified members. Two members of this family, fertilin alpha and fertilin beta, form a heterodimeric protein that is required for sperm-egg fusion. Most recently, it has been shown that a third family member, meltrin alpha, is involved in myoblast fusion (Yagami-Hiromasa et al., 1995, Nature 377: 652-656). Using restriction fragment length polymorphism analysis of a DNA panel from an interspecific backcross, we have determined the chromosomal locations of four mouse genes of this family that are expressed in testis: fertilin alpha, fertilin beta, ADAM 4, and ADAM 5. These genes have been given the locus symbols Ftna (fertilin alpha), Ftnb (fertilin beta), Adam4 (ADAM 4), and Adam5 (ADAM 5). They were mapped to chromosomes 5, 14, 9, and 8, respectively, revealing a dispersed localization. Human chromosome locations of these genes are predicted on the basis of the mapping results using the information provided by comparative linkage maps. Because all four of these ADAM genes are expressed in testis and fertilin alpha and beta have been found to be important for fertilization, we compared their chromosomal locations with known mouse mutations affecting spermatogenesis and fertility.
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Hunnicutt GR, Mahan K, Lathrop WF, Ramarao CS, Myles DG, Primakoff P. Structural relationship of sperm soluble hyaluronidase to the sperm membrane protein PH-20. Biol Reprod 1996; 54:1343-9. [PMID: 8724363 DOI: 10.1095/biolreprod54.6.1343] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The sperm plasma membrane protein PH-20 has a hyaluronidase activity that enables acrosome-intact sperm to pass through the cumulus cell layer of the egg. In this study we analyzed the relationship of guinea pig PH-20 and the "classical" soluble hyaluronidase released at the time of the acrosome reaction of guinea pig sperm. PH-20 is a membrane protein, anchored in the plasma and inner acrosomal membranes by a glycosyl phosphatidyl inositol anchor. Several types of experiments indicate a structural relationship of PH-20 and the soluble hyaluronidase released during the acrosome reaction. First, an antiserum raised against purified PH-20 is positive in an immunoblot of the soluble protein fraction released during the acrosome reaction. In the released, soluble protein fraction, the anti-PH-20 antiserum recognizes a protein of approximately 64 kDa, i.e., identical in molecular mass to PH-20 (approximately 64 kDa). Second, the enzymatic activity of the released hyaluronidase is completely inhibited (100%) by the anti-PH-20 antiserum. Third, almost all (97%) of the soluble hyaluronidase is removed from the released protein fraction by a single pass through an affinity column made with an anti-PH-20 monoclonal antibody. These findings suggest that the released, soluble hyaluronidase is a soluble form of PH-20 (sPH-20). During the acrosome reaction, PH-20 undergoes endoproteolytic cleavage into two disulfide-linked fragments whereas the released sPH-20 is not cleaved, suggesting the possible activity of a membrane-bound endoprotease on PH-20. We searched for a cDNA encoding sPH-20 but none was found. This result suggests that sPH-20 may arise from the enzymatic release of PH-20 from its membrane anchor, possibly at the time of acrosome reaction.
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Cherr GN, Meyers SA, Yudin AI, VandeVoort CA, Myles DG, Primakoff P, Overstreet JW. The PH-20 protein in cynomolgus macaque spermatozoa: identification of two different forms exhibiting hyaluronidase activity. Dev Biol 1996; 175:142-53. [PMID: 8608861 DOI: 10.1006/dbio.1996.0102] [Citation(s) in RCA: 77] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
In these experiments, we have characterized the bifunctional sperm protein PH-20 in macaque sperm and studied its hyaluronidase activity. Intact sperm were evaluated before the acrosome reaction (AR), and a soluble form of PH-20 released during acrosomal exocytosis was also investigated. Western blots of SDS-PAGE of acrosome-intact sperm extracts revealed a 64-kDa form of PH-20 was recognized by a polyclonal antibody (R-10) raised in rabbits against purified, recombinant cynomolgus macaque sperm PH-20. The soluble components released during the AR which were recognized by the R-10 antibody included both the 64-kDa form and a 53-kDa form of PH-20. An ELISA-like procedure for determining PH-20 hyaluronidase activity indicated that acrosome-intact sperm exhibited two peaks of hyaluronidase activity near pH 4 and > or = pH 7. The majority of enzyme activity in acrosome-intact sperm extracts occurred at neutral pH, while the soluble hyaluronidase activity released at the AR was predominantly acid-active. Hyaluronidase activity of PH-20 at different pH optima was investigated using hyaluronic acid substrate gel electrophoresis, and results indicated that the 64-kDa polypeptide had a broad range, with the majority of activity at neutral pH (pH 7). The 53-kDa polypeptide in sperm extracts only exhibited activity at acid pH (pH 4). The hyaluronidase activities of both enzymes could be inhibited by apigenin. The soluble PH-20 hyaluronidase activity released during the AR was primarily of the acid-active 53-kDa form. Fine structural localization of PH-20 using Fab fragments of R-10 IgG demonstrated that PH-20 was associated not only with sperm membranes, but also with the dispersing acrosomal contents. These data suggest that the more neutral-active form of PH-20 (64 kDa) is present on the plasma and inner acrosomal membranes and gives rise to the soluble acid-active form at the time of the AR. The generation of the soluble form of PH-20 may result from the action of acrosomal enzymes, which could include proteases, glycosidases, and phospholipases.
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Ramarao CS, Myles DG, White JM, Primakoff P. Initial evaluation of fertilin as an immunocontraceptive antigen and molecular cloning of the cynomolgus monkey fertilin beta subunit. Mol Reprod Dev 1996; 43:70-5. [PMID: 8720115 DOI: 10.1002/(sici)1098-2795(199601)43:1<70::aid-mrd9>3.0.co;2-r] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Fertilin (PH-30) is a sperm surface protein that functions in sperm adhesion and fusion with the egg plasma membrane. Because of its essential function in fertilization, fertilin is a potential target for novel contraceptive approaches. In a pilot fertility trial, immunization of male guinea pigs with purified guinea pig fertilin resulted in complete infertility. The contraceptive effect was partial (two out of six animals were infertile) when female guinea pigs were immunized with the antigen. These results suggest that fertilin or domains of fertilin may be effective as immunocontraceptive antigens. As a step toward achieving this goal, we communicate the cDNA and deduced amino acid sequence of the monkey fertilin beta subunit.
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Wolfsberg TG, Primakoff P, Myles DG, White JM. ADAM, a novel family of membrane proteins containing A Disintegrin And Metalloprotease domain: multipotential functions in cell-cell and cell-matrix interactions. J Cell Biol 1995; 131:275-8. [PMID: 7593158 PMCID: PMC2199973 DOI: 10.1083/jcb.131.2.275] [Citation(s) in RCA: 368] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
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Almeida EA, Huovila AP, Sutherland AE, Stephens LE, Calarco PG, Shaw LM, Mercurio AM, Sonnenberg A, Primakoff P, Myles DG, White JM. Mouse egg integrin alpha 6 beta 1 functions as a sperm receptor. Cell 1995; 81:1095-104. [PMID: 7600577 DOI: 10.1016/s0092-8674(05)80014-5] [Citation(s) in RCA: 396] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Binding between sperm and egg plasma membranes is an essential step in fertilization. Whereas fertilin, a mammalian sperm surface protein, is involved in this crucial interaction, sperm receptors on the egg plasma membrane have not been identified. Because fertilin contains a predicted integrin ligand domain, we investigated the expression and function of integrin subunits in unfertilized mouse eggs. Polymerase chain reactions detected mRNAs for alpha 5, alpha 6, alpha v, beta 1, beta 3, and beta 5. Immunofluorescence revealed alpha 6 beta 1 and alpha v beta 3 on the plasma membrane. GoH3, a function-blocking anti-alpha 6 monoclonal antibody, abolished sperm binding, but a nonfunction-blocking anti-alpha 6 monoclonal antibody, a function-blocking anti-alpha v beta 3 polyclonal antibody, and an RGD peptide had no effect. Somatic cells bound sperm avidly, but only if they expressed alpha 6 beta 1. A peptide analog of the fertilin integrin ligand domain inhibited sperm binding to eggs and alpha 6 beta 1+ cells and diminished GoH3 staining of eggs. Our results indicate a novel role for the integrin alpha 6 beta 1 as a cell-cell adhesion receptor that mediates sperm-egg binding.
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Wolfsberg TG, Straight PD, Gerena RL, Huovila AP, Primakoff P, Myles DG, White JM. ADAM, a widely distributed and developmentally regulated gene family encoding membrane proteins with a disintegrin and metalloprotease domain. Dev Biol 1995; 169:378-83. [PMID: 7750654 DOI: 10.1006/dbio.1995.1152] [Citation(s) in RCA: 290] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Fertilin alpha and beta, previously known as PH-30 alpha and beta, are two subunits of a guinea pig sperm integral membrane protein implicated in sperm-egg binding and fusion. They are derived from sequence-similar precursors which contain a metalloprotease-like and a disintegrin-like domain and which are related to a family of metalloprotease and disintegrin domain-containing snake venom proteins. We report here the cloning, sequencing, and characterization of mouse fertilin alpha and beta as well as five additional sequence-similar cDNAs from guinea pig and mouse testis. We name this gene family ADAM, for proteins containing A Disintegrin And Metalloprotease domain, and in honor of its dual origins in the fields of snakes and fertility. In situ hybridization demonstrated that, in testis, RNA encoding these ADAMs is expressed only in spermatogenic cells and that this expression is developmentally regulated. PCR analysis of mouse tissue cDNA showed that these ADAMs display different patterns of tissue distribution. Some ADAMs (e.g., fertilin alpha) have the consensus active-site sequence for a zinc-dependent metalloprotease in their metalloprotease-like domain. All have a disintegrin-like domain, which could bind integrins or other receptors. Some have sequences which may be active in membrane fusion. All encode potential membrane-spanning domains. Searches of sequence databases revealed that additional mammalian members of the ADAM gene family have been cloned from a variety of tissues. Thus, the ADAMs are a large, widely expressed, and developmentally regulated family of proteins with multiple potential functions in cell-cell and cell-matrix interactions.
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Overstreet JW, Lin Y, Yudin AI, Meyers SA, Primakoff P, Myles DG, Katz DF, Vandevoort CA. Location of the PH-20 protein on acrosome-intact and acrosome-reacted spermatozoa of cynomolgus macaques. Biol Reprod 1995; 52:105-14. [PMID: 7711169 DOI: 10.1095/biolreprod52.1.105] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Fluorescence microscopy and transmission electron microscopy (TEM) were used to determine the location of the membrane protein PH-20 on spermatozoa of cynomolgus macaques. Rabbit antiserum raised against recombinant cynomolgus macaque sperm PH-20 was used as the primary antibody, and the second antibody was goat anti-rabbit IgG conjugated with either fluorescein isothiocyanate or 15 nm gold particles. Spermatozoa were evaluated before capacitation and after capacitation and induction of acrosome reactions with calcium ionophore A23187. In sperm suspensions with a high percentage of intact acrosomes, fluorescence labeling was observed uniformly over most of the sperm head. The sperm midpiece and tail were not labeled. In sperm suspensions with a high percentage of acrosome reactions, most spermatozoa labeled intensely over the anterior sperm head, but labeling of the posterior sperm head was greatly reduced. TEM of acrosome-intact spermatozoa revealed gold particles distributed uniformly on the plasma membrane overlying the acrosome, the equatorial segment, and most of the post-acrosomal region. After the acrosome reaction, gold label was present on the inner acrosomal membrane and on the plasma membrane overlying the equatorial segment. Very little label was present on the plasma membrane in the post-acrosomal region of acrosome-reacted spermatozoa. The location of PH-20 on the surface of macaque spermatozoa suggests a function for this protein in primary and/or secondary binding to the zona pellucida. The apparent decrease in amount of PH-20 on the posterior head of macaque spermatozoa following the acrosome reaction is consistent with the migration of this protein to the inner acrosomal membrane, as demonstrated previously for the homologous PH-20 protein of guinea pig spermatozoa.
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Lin Y, Mahan K, Lathrop WF, Myles DG, Primakoff P. A hyaluronidase activity of the sperm plasma membrane protein PH-20 enables sperm to penetrate the cumulus cell layer surrounding the egg. J Biophys Biochem Cytol 1994; 125:1157-63. [PMID: 8195297 PMCID: PMC2120058 DOI: 10.1083/jcb.125.5.1157] [Citation(s) in RCA: 196] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
A typical mammalian egg is surrounded by an outer layer of about 3,000 cumulus cells embedded in an extracellular matrix rich in hyaluronic acid. A current, widely proposed model is that the fertilizing sperm, while it is acrosome intact, passes through the cumulus cell layer and binds to the egg zona pellucida. This current model lacks a well-supported explanation for how sperm penetrate the cumulus layer. We report that the sperm protein PH-20 has a hyaluronidase activity and is present on the plasma membrane of mouse and human sperm. Brief treatment with purified, recombinant PH-20 can release all the cumulus cells surrounding mouse eggs. Acrosome intact mouse sperm incubated with anti-PH-20 antibodies can not pass through the cumulus layer and thus can not reach the zona pellucida. These results, indicating that PH-20 enables acrosome intact sperm to penetrate the cumulus barrier, reveal a mechanism for cumulus penetration, and thus provide the missing element in the current model.
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Myles DG, Kimmel LH, Blobel CP, White JM, Primakoff P. Identification of a binding site in the disintegrin domain of fertilin required for sperm-egg fusion. Proc Natl Acad Sci U S A 1994; 91:4195-8. [PMID: 8183890 PMCID: PMC43751 DOI: 10.1073/pnas.91.10.4195] [Citation(s) in RCA: 190] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Fertilization and certain later stages in mammalian embryonic development require fusion between membranes of individual cells. The mechanism of eukaryotic cell-cell fusion is unknown, and no surface molecules required for this process have been unequivocally identified. The role of the sperm surface protein fertilin in sperm-egg fusion was tested by using peptide analogues of a potential integrin binding site in the fertilin beta subunit. Peptide analogues that include a TDE sequence from the disintegrin region of fertilin beta are able to bind to the egg plasma membrane and strongly inhibit sperm-egg fusion. These results show that the disintegrin domain of fertilin beta binds to the egg plasma membrane and that this binding is required for membrane fusion.
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Wolfsberg TG, Bazan JF, Blobel CP, Myles DG, Primakoff P, White JM. The precursor region of a protein active in sperm-egg fusion contains a metalloprotease and a disintegrin domain: structural, functional, and evolutionary implications. Proc Natl Acad Sci U S A 1993; 90:10783-7. [PMID: 8248170 PMCID: PMC47862 DOI: 10.1073/pnas.90.22.10783] [Citation(s) in RCA: 136] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
PH-30, a sperm surface protein involved in sperm-egg fusion, is composed of two subunits, alpha and beta, which are synthesized as precursors and processed, during sperm development, to yield the mature forms. The mature PH-30 alpha/beta complex resembles certain viral fusion proteins in membrane topology and predicted binding and fusion functions. Furthermore, the mature subunits are similar in sequence to each other and to a family of disintegrin domain-containing snake venom proteins. We report here the sequences of the PH-30 alpha and beta precursor regions. Their domain organizations are similar to each other and to precursors of snake venom metalloproteases and disintegrins. The alpha precursor region contains, from amino to carboxyl terminus, pro, metalloprotease, and disintegrin domains. The beta precursor region contains pro and metalloprotease domains. Residues diagnostic of a catalytically active metalloprotease are present in the alpha, but not the beta, precursor region. We propose that the active sites of the PH-30 alpha and snake venom metalloproteases are structurally similar to that of astacin. PH-30, acting through its metalloprotease and/or disintegrin domains, could be involved in sperm development as well as sperm-egg binding and fusion. Phylogenetic analysis indicates that PH-30 stems from a multidomain ancestral protein.
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