scholarly journals Sperm plasma membrane breakdown during Drosophila fertilization requires Sneaky, an acrosomal membrane protein

Development ◽  
2006 ◽  
Vol 133 (24) ◽  
pp. 4871-4879 ◽  
Author(s):  
K. L. Wilson ◽  
K. R. Fitch ◽  
B. T. Bafus ◽  
B. T. Wakimoto
Keyword(s):  
Plasma Membrane ◽  
Membrane Protein ◽  
Membrane Breakdown ◽  
Acrosomal Membrane ◽  
Sperm Plasma Membrane

scholarly journals ROLE OF THE GAMETE MEMBRANES IN FERTILIZATION IN SACCOGLOSSUS KOWALEVSKII (ENTEROPNEUSTA)

1963 ◽  
Vol 19 (3) ◽  
pp. 477-500 ◽  
Author(s):  
Arthur L. Colwin ◽  
Laura Hunter Colwin
Keyword(s):  
Plasma Membrane ◽  
Osmium Tetroxide ◽  
Plasma Membranes ◽  
Previous Evidence ◽  
Egg Envelope ◽  
Saccoglossus Kowalevskii ◽  
Acrosomal Membrane ◽  
Peripheral Ring ◽  
Sperm Plasma Membrane

Previous electron microscope studies of sperm-egg association in the annelid Hydroides revealed novel aspects with respect to the acrosomal region. To determine whether these aspects were unique, a comparable study was made of a species belonging to a widely separated phylum, Hemichordata. Osmium tetroxide-fixed polyspermic material of the enteropneust, Saccoglossus, was used. The acrosomal region includes the membrane-bounded acrosome, with its large acrosomal granule and shallow adnuclear invagination, and the periacrosomal material which surrounds the acrosome except at the apex; here, the acrosomal membrane lies very close to the enclosing sperm plasma membrane. After reaching the egg envelope, the spermatozoon is activated and undergoes a series of changes: the apex dehisces and around the resulting orifice the acrosomal and sperm plasma membranes form a continuous mosaic membrane. The acrosomal granule disappears. Within 7 seconds the invagination becomes the acrosomal tubule, spans the egg envelopes, and meets the egg plasma membrane. The rest of the acrosomal vesicle everts. The periacrosomal mass changes profoundly: part becomes a fibrous core (possibly equivalent to a perforatorium); part remains as a peripheral ring. The basic pattern of structure and sperm-egg association in Saccoglossus is the same as in Hydroides. Previous evidence from four other phyla as interpreted here also indicates conformity to this pattern. The major role of the acrosome is apparently to deliver the sperm plasma membrane to the egg plasma membrane.

scholarly journals CHANGES IN THE SPERMATOZOON DURING FERTILIZATION IN HYDROIDES HEXAGONUS (ANNELIDA)

1961 ◽  
Vol 10 (2) ◽  
pp. 231-254 ◽  
Author(s):  
Laura Hunter Colwin ◽  
Arthur L. Colwin
Keyword(s):  
Plasma Membrane ◽  
Outer Zone ◽  
Sperm Head ◽  
Intermediate Zone ◽  
Vitelline Membrane ◽  
Acrosomal Vesicle ◽  
Acrosomal Membrane ◽  
Sperm Plasma Membrane ◽  
Morphological Identity

In the previous paper the structure of the acrosomal region of the spermatozoon was described. The present paper describes the changes which this region undergoes during passage through the vitelline membrane. The material used consisted of moderately polyspermic eggs of Hydroides hexagonus, osmium-fixed usually 9 seconds after insemination. There are essentially four major changes in the acrosome during passage of the sperm head through the vitelline membrane. First, the acrosome breaks open apically by a kind of dehiscence which results in the formation of a well defined orifice. Around the lips of the orifice the edges of the plasma and acrosomal membranes are then found to be fused to form a continuous membranous sheet. Second, the walls of the acrosomal vesicle are completely everted, and this appears to be the means by which the apex of the sperm head is moved through the vitelline membrane. The lip of the orifice comes to lie deeper and deeper within the vitelline membrane. At the same time the lip itself is made up of constantly changing material as first the material of the outer zone and then that of the intermediate zone everts. One is reminded of the lip of an amphibian blastopore, which during gastrulation maintains its morphological identity as a lip but is nevertheless made up of constantly changing cells, with constantly changing outline and even constantly changing position. Third, the large acrosomal granule rapidly disappears. This disappearance is closely correlated with a corresponding disappearance of a part of the principal material of the vitelline membrane from before it, and the suggestion is made that the acrosomal granule is the source of the lysin which dissolves this part of the vitelline membrane. Fourth, in the inner zone the fifteen or so short tubular invaginations of the acrosomal membrane, present in the normal unreacted spermatozoon, lengthen considerably to become a tuft of acrosomal tubules. These tubules are the first structures of the advancing sperm head to touch the plasma membrane of the egg. It is notable that the surface of the acrosomal tubules which once faced into the closed acrosomal cavity becomes the first part of the sperm plasma membrane to meet the plasma membrane of the egg. The acrosomal tubules of Hydroides, which arise simply by lengthening of already existing shorter tubules, are considered to represent the acrosome filaments of other species.

scholarly journals Role of actin cytoskeleton in mammalian sperm capacitation and the acrosome reaction

Reproduction ◽  
2005 ◽  
Vol 129 (3) ◽  
pp. 263-268 ◽  
Author(s):  
Haim Breitbart ◽  
Gili Cohen ◽  
Sara Rubinstein
Keyword(s):  
Plasma Membrane ◽  
Zona Pellucida ◽  
Acrosome Reaction ◽  
Reproductive Tract ◽  
Female Reproductive Tract ◽  
Mammalian Sperm ◽  
Acrosomal Membrane ◽  
Close Proximity ◽  
Sperm Plasma Membrane ◽  
To Come

In order to fertilize, the mammalian spermatozoa should reside in the female reproductive tract for several hours, during which they undergo a series of biochemical modifications collectively called capacitation. Only capacitated sperm can undergo the acrosome reaction after binding to the egg zona pellucida, a process which enables sperm to penetrate into the egg and fertilize it. Polymerization of globular (G)-actin to filamentous (F)-actin occurs during capacitation, depending on protein kinase A activation, protein tyrosine phosphorylation, and phospholipase D activation. F-actin formation is important for the translocation of phospholipase C from the cytosol to the sperm plasma membrane during capacitation. Prior to the occurrence of the acrosome reaction, the F-actin should undergo depolymerization, a necessary process which enables the outer acrosomal membrane and the overlying plasma membrane to come into close proximity and fuse. The binding of the capacitated sperm to the zona pellucida induces a fast increase in sperm intracellular calcium, activation of actin severing proteins which break down the actin fibers, and allows the acrosome reaction to take place.

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