Actin in Human Spermatozoa

Clarke, Gary N.; Clarke, Frank M.; Wilson, Shann

doi:10.1095/biolreprod26.2.319

Cited by 82 publications

(35 citation statements)

References 6 publications

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“…The antigen-antibody reaction was assessed by the secondary antibody tagged to 10 nm gold particles and the reaction complex was fixed with osmium tetroxide thereby achieving a dual effect of contrast enhancement. The consistency of the method despite the use of weak fixative cocktail is apparent from the results on actin localization and the antigenic distribution seen here which are very similar to those seen by others using immunofluorescence (Clarke et al, 1982;Flaherty et al, 1988;Virtanen et al, 1984;Vogl, 1989). Indirect immunogold studies on sperm sections from boar (Casale et al, 1988) and guinea pig (Herná ndezGonzá lez et al, 2000) have identified presence of actin in the acrosomal region.…”

Section: Immunogold Localization Of B-tubulinsupporting

confidence: 86%

Spatial Distribution of Actin and Tubulin in Human Sperm Nuclear Matrix‐intermediate Filament Whole Mounts—A New Paradigm

Kadam¹,

D’Souza²,

Natraj³

2007

Microscopy Res & Technique

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Sperm is a highly differentiated cell streamlined for fertilization. The function is thus heavily dependent on the cytoskeletal organization. Conventional methods limit the appreciation and correlation of this intricate cytoskeletal filament network in the context of an entire sperm. Our recent successful localization of nonmuscle myosin IIA on sperm nuclear matrix-intermediate filament (NM-IF) preparations from fertile men by embedment-free electron microscopy (EF-EM), prompted us to investigate the antigenic distribution of two major cytoskeletal proteins-actin and tubulin. The NM-IF preparations were subjected to a cocktail of buffered paraformaldehyde (2%) with a low concentration of glutaraldehyde (0.05%). These proteins were localized by indirect immunogold technique using EF-EM on sperm NM-IF whole mounts. Ultrastructure analysis revealed well preserved centrioles, outer dense fibers, axonemal filaments, and submitochondrial reticulum in the sperm NM-IF. Immunoreactive actin was localized along the length of the sperm whereas beta-tubulin was present in the axoneme alone. The spatial distribution of actin and tubulin in normal human sperm NM-IF reported here together with that of myosin on whole mount offers a powerful technique to understand sperm cytoskeletal supramolecular structure.

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Section: Immunogold Localization Of B-tubulinsupporting

confidence: 86%

Spatial Distribution of Actin and Tubulin in Human Sperm Nuclear Matrix‐intermediate Filament Whole Mounts—A New Paradigm

Kadam¹,

D’Souza²,

Natraj³

2007

Microscopy Res & Technique

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“…In mammalian sperm, the perforatorium, exposed once the acrosome reaction has released the hydrolytic contents of the acrosomal cap and collar, acts as a mechanical tool with which the spermatozoan cuts through the zona pellucida of the egg (35). Actin in mammalian sperm may play a role in membrane fusions leading to the acrosome reaction and sperm-egg fusion since actin is present in the sperm tail, connecting piece, and posterior region of the sperm head in human and hamster sperm (6,31) and in the postacrosomal region of sperm from eight mammalian species, including mice (7; J. E. Welch and M. G. O'Rand, Dev. Biol., in press).…”

Section: Discussionmentioning

confidence: 99%

Mouse testes contain two size classes of actin mRNA that are differentially expressed during spermatogenesis.

Waters¹,

Distel²,

Hecht³

1985

Mol. Cell. Biol.

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Using several actin isotype-specific cDNA probes, we found actin mRNA of two size classes, 2.1 and 1.5 kilobases (kb), in extracts of polyadenylated and nonpolyadenylated RNA from sexually mature CD-1 mouse testes. Although the 2.1-kb sequence was present in both meiotic and postmeiotic testicular cell types, it decreased manyfold in late haploid cells. The 1.5-kb actin sequence was not detectable in meiotic pachytene spermatocytes (or in liver or kidney cells), but was present in round and elongating spermatids and residual bodies. To differentiate between the I8-and y-actin mRNAs, we isolated a cDNA, pMGA, containing the 3' untranslated region of a mouse cytoplasmic actin that has homology to the 3' untranslated region of a human -y-actin cDNA but not to the 3' untranslated regions of human a-, i-, or cardiac actins. Dot blot hybridizations with pMGA detected high levels of presumptive -y-actin mRNA in pachytene spermatocytes and round spermatids, with lower amounts found in elongating spermatids. Hybridization with the 3' untranslated region of a rat 0-actin probe revealed that round spermatids contained higher levels of 3-actin mRNA than did pachytene spermatocytes or residual bodies. Both probes hybridized to the 2.1-kb actin mRNA but failed to hybridize to the 1.5-kb mRNA.The actins are believed to play major roles in cell division, cell shape changes, secretory processes, phagocytosis, cell and organelle motility, and muscle contraction (1,8,11 elongating spermatids. In contrast, the amount of radiolabeled ,B-actin increases between pachytene spermatocytes and the subsequent postmeiosis spermatids. Thus, although the rate of total cytoplasmic actin labeling appears not to vary greatly during spermatogenesis, the proportion of 1-and y-actin synthesis changes. It has been suggested that the differential expression of 1B-and -y-actin during spermatogenesis plays a role in the changing cell shapes or in the movement of mitochondria from around the nucleus to the plasma membrane and the flagellar axoneme which occurs during this developmental process (2, 16). In this paper we examine actin mRNA transcripts during spermatogenesis in mice by using several actin isotypespecific cDNA probes. We find that two size classes of actin mRNA are present in mouse testes, one in both meiotic and postmeiotic cells, the other first detected in postmeiotic cells. Hybridization with isotype-specific cDNA probes revealed quantitative changes in the levels of 1-and ly-actin mRNAs during spermatogenesis. MATERIALS AND METHODSIsolation and purification of spermatogenic cells. CD-1 mice at least 60 days old were obtained from Charles River Breeding Laboratories. Suspensions of spermatogenic cells were prepared by collagenase dissociation and separated by sedimentation on bovine serum albumin gradients at unit gravity as previously described (13, 18, 22, 23, 28). Fractions containing pachytene spermatocytes, round spermatids, elongating spermatids, and residual bodies were identified by Nomarski interference microscopy by using the ...

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“…A rigid postacrosomal sheath is a putative site for actin in a number of mammalian spermatozoa (Clarke and Yanagimachi, 1978;Tamblyn, 1980;Clarke et al, 1982;Flaherty et al, 1986Flaherty et al, , 1988Yagi and Paranko, 1992), where it may interact with actin-binding proteins such as spectrin (Kann et al, 1993) and a group of basic proteins including calicin and multiple band proteins (Longo et al, 1987;Paranko et al, 19881, and with less well identified silver binding proteins (Yagi and Paranko, 1994).…”

Section: Lmmunolocalization Ofmentioning

confidence: 99%

Actin, α‐actinin, and spectrin with specific associations with the postacrosomal and acrosomal domains of bovine spermatozoa

Yagi

Paranko

1995

Anat. Rec.

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Destabilization of membranes with selected extractions induces changes in the acrosomal lamina mimicking acrosomal vesicle formation. The lateral prongs and posterior ring structure, respectively, may serve as anterior and posterior anchors for the extraction-resistant post-acrosomal sheath. The lateral prongs may also be a merger zone for actin, alpha-actinin, and spectrin with important implication on sperm function. The latter two proteins may be involved in acrosomal vesicle formation. It is apparent that extractions have a significant effect on the detectability of sperm cytoskeletal elements.

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Actin in Human Spermatozoa

Cited by 82 publications

References 6 publications

Spatial Distribution of Actin and Tubulin in Human Sperm Nuclear Matrix‐intermediate Filament Whole Mounts—A New Paradigm

Spatial Distribution of Actin and Tubulin in Human Sperm Nuclear Matrix‐intermediate Filament Whole Mounts—A New Paradigm

Mouse testes contain two size classes of actin mRNA that are differentially expressed during spermatogenesis.

Actin, α‐actinin, and spectrin with specific associations with the postacrosomal and acrosomal domains of bovine spermatozoa

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