Tracing sperm acrosome differentiation in the testis and maturation in the epididymis of the tammar wallaby (Macropus eugenii) with a 45-kDa acrosome-membrane-associated protein

2002 ◽  
Vol 14 (2) ◽  
pp. 69
Author(s):  
Xiyi Zhang ◽  
Minjie Lin
Keyword(s):  
Molecular Marker ◽  
Tammar Wallaby ◽  
Sperm Nucleus ◽  
Macropus Eugenii ◽  
Acrosomal Membrane ◽  
Epididymal Maturation ◽  
Associated Proteins ◽  
Inner Acrosomal Membrane ◽  
Sperm Acrosome

A 45-kDa protein was originally extracted from a depression, where the acrosome is lodged, on the anterior end of the sperm nucleus of ejaculated wallaby spermatozoa. Using immunofluorescent and confocal microscopes, this study demonstrates that the 45-kDa protein is persistently localized to the sperm acrosome throughout the periods of spermiogenesis, spermiation, epididymal maturation and ejaculation in the tammar wallaby. The distribution of the 45-kDa protein is always on the perimeter of the acrosome and associated with the acrosomal membrane, so that changes in the shape of the 45-kDa immunofluorescent labelling mirror changes in the shape of the acrosome during its differentiation in the testis and epididymis. Thus, the 45-kDa protein may be used as a molecular marker to study the marsupial acrosome differentiation and to chart the events of testicular and epididymal maturation of the spermatozoa. Furthermore, the behaviour of the 45-kDa protein during the immunostaining process suggests that this protein is a largely insoluble and detergent-resistant protein and may play an important role in attachment of the acrosome to the nucleus during sperm formation, similar to those inner acrosomal-membrane-associated proteins that have been reported in eutherian spermatozoa.

Arachidonic acid-induced acrosomal loss in the spermatozoa of a marsupial, the tammar wallaby (Macropus eugenii)

1997 ◽  
Vol 9 (8) ◽  
pp. 803 ◽  
Author(s):  
Yulia Sistina ◽  
John C. Rodger
Keyword(s):  
Arachidonic Acid ◽  
Plasma Membrane ◽  
Membrane Fusion ◽  
Tammar Wallaby ◽  
Multiple Point ◽  
Fusion Event ◽  
Macropus Eugenii ◽  
Kinase C ◽  
Acrosomal Membrane ◽  
Late Stages

Tammar wallaby spermatozoa were induced to undergo acrosomal loss when incubated with arachidonic acid (AA). Ultrastructural examination indicated that the AA-induced acrosomal loss occurred via multiple point fusions between the outer acrosomal membrane and the overlying plasma membrane. This form of acrosomal loss mimicked the physiological acrosome reaction (AR) seen in the sperm of eutherian mammals. The fusion event was limited to the acrosomal region of the plasma membrane and did not proceed past the peri-acrosomal ring. The entire acrosome was lost after AA treatment leaving no evidence of a persistent equatorial segment-like region. Ultrastructural evidence of AR-like membrane fusion was seen immediately on addition of 50 µg mL-1 AA and a large proportion of sperm examined after five min incubation were in the late stages of membrane fusion. Longer-term incubation with AA had deleterious effects on wallaby sperm motility. It remains to be determined whether the AA-induced membrane fusion observed here indicates that AA is involved in the marsupial AR. However, pretreatment of sperm with the protein kinase C (PKC) inhibitor HMG significantly reduced AA-induced acrosomal loss suggesting that AA may have acted via PKC. If this is so, AA is probably physiologically significant and a novel pathway may be operating during AR induction in marsupials.

scholarly journals Disruption of Mouse CD46 Causes an Accelerated Spontaneous Acrosome Reaction in Sperm

2003 ◽  
Vol 23 (7) ◽  
pp. 2614-2622 ◽  
Author(s):  
Naokazu Inoue ◽  
Masahito Ikawa ◽  
Tomoko Nakanishi ◽  
Misako Matsumoto ◽  
Midori Nomura ◽  
...  
Keyword(s):  
Homologous Recombination ◽  
Acrosome Reaction ◽  
Null Mutation ◽  
Membrane Cofactor Protein ◽  
Wild Type ◽  
Acrosomal Membrane ◽  
Fertilizing Ability ◽  
Inner Acrosomal Membrane ◽  
Sperm Acrosome Reaction ◽  
Sperm Acrosome

ABSTRACT Human membrane cofactor protein (MCP, CD46) is a ubiquitously expressed protein known to protect cells from complement attack. Interestingly, when we examined the expression of mouse CD46, which we recently cloned, the message was found only in testis and the protein was found on the inner acrosomal membrane of sperm. In order to elucidate the function of CD46, we produced mice carrying a null mutation in the CD46 gene by using homologous recombination. Despite the absence of CD46, the mice were healthy and both sexes were fertile. However, to our surprise, the fertilizing ability of males appeared to be facilitated by disruption of the CD46 gene, as the average number of pups born from CD46−/− males was significantly greater than that of wild-type males. It was also revealed that the incidence of the spontaneous acrosome reaction doubled in CD46−/− sperm compared to that in wild-type sperm. It was assumed that this increase caused the heightened fertilizing ability found in CD46−/− sperm. These data suggest that CD46 may have some role in regulating sperm acrosome reaction.

scholarly journals Acrosome formation during sperm transit through the epididymis in two marsupials, the tammar wallaby (Macropus eugenii) and the brushtail possum (Trichosurus vulpecula)

1999 ◽  
Vol 194 (2) ◽  
pp. 223-232
Author(s):  
MINJIE LIN ◽  
JOHN C. RODGER
Keyword(s):  
Spatial Information ◽  
Dorsal Surface ◽  
Tammar Wallaby ◽  
Sperm Head ◽  
The Body ◽  
Brushtail Possum ◽  
Trichosurus Vulpecula ◽  
Macropus Eugenii ◽  
Acrosomal Membrane ◽  
Acrosome Formation

In certain Australian marsupials including the tammar wallaby (Macropus eugenii) and the brushtail possum (Trichosurus vulpecula), formation of the acrosome is not completed in the testis but during a complex differentiation process as spermatozoa pass through the epididymis. Using transmission and scanning electron microscopy this paper defined the process of acrosome formation in the epididymis, providing temporal and spatial information on the striking reorganisation of the acrosomal membranes and matrix and of the overlying sperm surface involved. On leaving the testis wallaby and possum spermatozoa had elongated ‘scoop’-shaped acrosomes projecting from the dorsal surface of the head. During passage down the epididymis, this structure condensed into the compact button-like organelle found on ejaculated spermatozoa. This condensation was achieved by a complex process of infolding and fusion of the lateral projections of the ‘scoop’. In the head of the epididymis the rims of the lateral scoop projections became shorter and thickened and folded inwards, to eventually meet midway along the longitudinal axis of the acrosome. As spermatozoa passed through the body of the epididymis the lateral projections fused together. Evidence of this fusion of the immature outer acrosomal membrane is the presence of vesicles within the acrosomal matrix which persist even in ejaculated spermatozoa. When spermatozoa have reached the tail of the epididymis the acrosome condenses into its mature form, as a small button-like structure contained within the depression on the anterior end of the nucleus. During the infolding process, the membranes associated with the immature acrosome are either engulfed into the acrosomal matrix (outer acrosomal membrane), or eliminated from the sperm head as tubular membrane elements (cytoplasmic membrane). Thus the surface and organelles of the testicular sperm head are transient structures in those marsupials with posttesticular acrosome formation and this must be taken into consideration in attempts to dissect the cell and molecular biology of fertilisation.

scholarly journals Growth of the corpus luteum and its progesterone content during pregnancy in the tammar wallaby, Macropus eugenii

Reproduction ◽  
1979 ◽  
Vol 57 (1) ◽  
pp. 131-136 ◽  
Author(s):  
M. B. Renfree ◽  
S. W. Green ◽  
I. R. Young
Keyword(s):  
Corpus Luteum ◽  
Tammar Wallaby ◽  
Macropus Eugenii
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