Morphology of abalone spermatozoa before and after the acrosome reaction

Lewis, Cindy; Leighton, D. L.; Vacquier, Victor D.

doi:10.1016/s0022-5320(80)90133-1

Cited by 56 publications

(35 citation statements)

References 21 publications

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“…Cloning and Sequencing of cDNAs Coding for Pink and Red Abalone Lysin. The abalone spermatozoon has an enormous acrosome granule (1,9), and we had previously shown that lysin is the most abundant protein in the cell (1). The rabbit antibody to chromatographically purified lysin (7) reacts monospecifically with only the lysin band on Western immunoblots of whole abalone sperm (not shown).…”

Section: Resultsmentioning

confidence: 97%

Species-specific sequences of abalone lysin, the sperm protein that creates a hole in the egg envelope.

Vacquier¹,

Carner²,

Stout³

1990

Proc. Natl. Acad. Sci. U.S.A.

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Abalone eggs are contained within a rigid, elevated vitelline envelope through which the sperm must pass before reaching the egg cell membrane. Abalone spermatozoa possess an acrosomal protein called iysin that creates a hole in the egg vitelline envelope by a nonenzymatic mechanism. Lysins from two species ofabalone, termed pink and red, which share the same habitat, exhibit species specificity in the dissolution of isolated egg envelopes. Cloning and sequencing the cDNAs for pink and red abalone lysins reveal transcript lengths of -660 nucleotides. The open reading frames of465 (pink) and 462 (red) nucleotides show a 13% difference. The 3' untranslated regions before the poly(A) tails are 170 (pink) and 165 (red) nucleotides long and differ from each other by about 7%. The protein sequences show nearly identical signal sequences of 18 amino acids for both lysins. The mature protein is 137 amino acids in the pink abalone and 136 in the red abalone; the two mature lysins differ in 29 of 137 amino acids (21%). The most variable region, which may account for lysin's species specificity, is at the NH2 terminus, where 11 of the 15 amino acids differ between the two species. Predictions of secondary structure indicate that both lysins contain four homologous amphiphilic a-helices.In animals the fusion of sperm and egg during fertilization is preceded by several events mediated by gamete recognition proteins. These events include the adhesion of sperm to the egg envelope, the induction of the acrosome reaction by components ofthe egg's extracellular matrix, and penetration of the sperm through the egg envelope. When cross-species fertilization is attempted, blocks to these events can be demonstrated depending on the particular species combinations being studied. Such blocks to cross-species fertilization can be readily demonstrated in congeneric species of marine invertebrates that share the same habitat, have overlapping breeding seasons, and release their gametes to the seawater where fertilization occurs. Knowledge of the proteins (and their genes) that mediate the species-specific events of sperm-egg interaction is important for understanding the molecular mechanisms of fertilization. It will also be important in understanding the evolution of the mechanisms that prevent successful sperm-egg interaction and ultimately create barriei to reproduction between species.Abalone Lre large archeogastropod molluscs of the genus Haliotis, eight species of which occur on the Pacific Coast of North America. The abalone egg is enclosed in an elevated glycoproteinaceous vitelline envelope (VE; -1 u.m in thickness) through which the spermatozoon must pass before it can fuse with the egg. During fertilization the abalone spermatozoon attaches to the VE, its acrosome granule opens, and two proteins of Mr -16,000 and =18,000 are released onto the VE. A hole 3 gm in diameter appears in seconds in the VE to allow the 1-Am (diameter) sperm to pass through this extracellular barrier (1). The Mr 16,000 protein (hereafter called ...

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Section: Resultsmentioning

confidence: 97%

Species-specific sequences of abalone lysin, the sperm protein that creates a hole in the egg envelope.

Vacquier¹,

Carner²,

Stout³

1990

Proc. Natl. Acad. Sci. U.S.A.

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“…How do sperm penetrate the VE? Abalone sperm have an unusually large acrosome granule (Lewis et al, 1980;Sakai et al, 1982). Microscopic observations of sperm-egg interaction reveal that few VE-bound sperm undergo the acrosome reaction.…”

Section: Abalone Fertilisationmentioning

confidence: 99%

Abalone sperm lysin: unusual mode of evolution of a gamete recognition protein

Vacquier

Lee

1993

Zygote

Self Cite

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“…In abalone sperm, a bundle of filaments termed the axial rod preexists in the subacrosomal region of the unreacted sperm head. This axial rod further elongates anteriorly to form an acrosomal process during the acrosome reaction [Lewis et al, 1980;Sakai et al, 19821, which is generated by further polymerization of G-actin as reported previously [Shiroya et al, 19861. However, in such a kind of mollusc, a more rigid structure termed the truncated cone seems to participate in fertilization with the acrosomal process Shiroya and Sakai, 19841.…”

Section: Discussionmentioning

confidence: 53%

“…ma and Dan, 1965;Lewis et al, 1980;Sakai et al, 19821, which are necessary for penetration of the sperm through protective egg coat into the egg.…”

mentioning

confidence: 99%

Analysis of the elongation of the coiled filamentous structure, the truncated cone, during the acrosome reaction of abalone sperm by computer simulation and quick‐freeze, deep‐etch electron microscopy

Sakai¹,

Shinagawa²,

Shiroya³

et al. 1993

Cell Motil. Cytoskeleton

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A novel structure named the truncated cone was located in the apex of the acrosomal vesicle right beneath the outer acrosomal membrane of abalone sperm head. This truncated cone structure was composed of about 12 helically coiled filaments, each 3.5-3.6 p m long with a diameter of 8-12 nm, forming a tightly compressed helicoid. During the acrosome reaction, the truncated cone elongated more than three times the original height and transformed into a thin cylinder by further coiling up of the filamcnts from the initial 2.5 to final 5 turns. The diameter and the length of each filamcnt did not change during the elongation of the truncated cone into thin cylinder.Calculation from the equation of helical movement (spiral motion) applying the actual values of the truncated cone structurc measured by electron microscopy gave the theoretical values nearly coincident with the actual measurements. The computer animation simulated the process of the moverncnt of the coiled filaments composing the truncated cone and suggested that the elongation of thc truncated cone into thin cylinder can be elucidated as a helical movement of the coiled filaments keeping their length constant.Quick-freeze, deep-etch electron microscopy further revealed that each of the coiled filaments was characterized by its beaded configuration, closely resembling that of the intermediate filaments of our previous results by immunoelectron microscopy and immunoblot analysis. The movement of the helically coiled filaments of the truncated cone may provide first example of the intermediate filaments to participate in motility and fertilization. Q 1993 WiIcy-Liss, Inc.

show abstract

Morphology of abalone spermatozoa before and after the acrosome reaction

Cited by 56 publications

References 21 publications

Species-specific sequences of abalone lysin, the sperm protein that creates a hole in the egg envelope.

Species-specific sequences of abalone lysin, the sperm protein that creates a hole in the egg envelope.

Abalone sperm lysin: unusual mode of evolution of a gamete recognition protein

Analysis of the elongation of the coiled filamentous structure, the truncated cone, during the acrosome reaction of abalone sperm by computer simulation and quick‐freeze, deep‐etch electron microscopy

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