Roles of actin networks in peristaltic squeezing of sperm bundles in <i>Bombyx mori</i>

Sahara, Ken; Kawamura, Naoko

doi:10.1002/jmor.10168

Cited by 23 publications

(17 citation statements)

References 12 publications

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“…This process requires proper F-actin dynamics with F-actin assembly occurring throughout the cone (Noguchi and Miller, 2003;Ghosh-Roy et al, 2005). Similar phenomenon has also been reported by Sahara and Kawamura (2004) in silkworm, Bombyx mori, and the dynamics of actin filaments appears to be the main force behind peristaltic squeezing of the sperm bundles as well.…”

Section: Role Of Actin Dynamics During Spermatogenesissupporting

confidence: 77%

Actin-based dynamics during spermatogenesis and its significance

Xiao

Yang

2007

J. Zhejiang Univ. - Sci. B

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Actin can be found in all kinds of eukaryotic cells, maintaining their shapes and motilities, while its dynamics in sperm cells is understood less than their nonmuscle somatic cell counterparts. Spermatogenesis is a complicated process, resulting in the production of mature sperm from primordial germ cell. Significant structural and biochemical changes take place in the seminiferous epithelium of the adult testis during spermatogenesis. It was proved that all mammalian sperm contain actin, and that F-actin may play an important role during spermatogenesis, especially in nuclear shaping. Recently a new model for sperm head elongation based on the acrosome-acroplaxome-manchette complex has been proposed. In Drosophila, F-actin assembly is supposed to be very crucial during individualization. In this mini-review, we provide an overview of the structure, function, and regulation characteristics of actin cytoskeleton, and a summary of the current status of research of actin-based structure and movement is also provided, with emphasis on the role of actins in sperm head shaping during spermiogenesis and the cell junction dynamics in the testis. Research of the Sertoli ectoplasmic specialization is in the spotlight, which is a testis-specific actin-based junction very important for the movement of germ cells across the epithelium. Study of the molecular architecture and the regulating mechanism of the Sertoli ectoplasmic specialization has become an intriguing field. All this may lead to a new strategy for male infertility and, at the same time, a novel idea may result in devising much safer contraception with high efficiency. It is hoped that the advances listed in this review would give developmental and morphological researchers a favorable investigating outline and could help to enlarge the view of new strategies and models for actin dynamics during spermatogenesis.

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Section: Role Of Actin Dynamics During Spermatogenesissupporting

confidence: 77%

Actin-based dynamics during spermatogenesis and its significance

Xiao

Yang

2007

J. Zhejiang Univ. - Sci. B

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“…During meiosis in the harlequin lobes, autosomes typically form a chain or become an indistinguishable mass that is laterally displaced from the normal mitotic axis and fails to segregate appropriately during cell division (Schrader, 1945, 1946 a , b , 1960 a ). Likewise, in Lepidoptera, changes in circulating hormones with the onset of pupation result in a shortened prophase and the elimination of nuclei from developing spermatids (Friedländer, 1997; Kawamura et al , 2003; Sahara & Kawamura, 2004).…”

Section: Evolutionary Patternsmentioning

confidence: 99%

Evolution of intra-ejaculate sperm interactions: do sperm cooperate?

2010

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Sperm are often considered to be individuals, in part because of their unique genetic identities produced as a result of synapsis during meiosis, and in part due to their unique ecology, being ejected away from the soma to continue their existence in a foreign environment. Selection at the level of individual sperm has been suggested to explain the evolution of two enigmatic sperm phenotypes: sperm heteromorphism, where more than one type of sperm is produced by a male, and sperm conjugation, where multiple sperm join together for motility and transport through the female reproductive tract before dissociation prior to fertilization. In sperm heteromorphic species, only one of the sperm morphs typically participates in fertilization, with the non-fertilizing "parasperm" being interpreted as reproductive altruists. Likewise, in species with sperm conjugation, high levels of sperm mortality have been suggested to be required for conjugate break-up and this has been considered evidence of kin-selected altruism. However, it is unclear if sperm possess the heritable variation in fitness (i.e. are individuals) required for the evolution of cooperation. We investigate the question of sperm individuality by focusing on how sperm morphology is determined and how sperm conjugates are formed. Concentrating on sperm conjugation, we discuss functional hypotheses for the evolutionary maintenance of this remarkable trait. Additionally, we speculate on the potential origins of sperm heteromorphism and conjugation, and explore the diversification and losses of these traits once they have arisen in a lineage. We find current evidence insufficient to support the concept of sperm control over their form or function. Thus, without additional evidence of haploid selection (i.e. sperm phenotypes that reflect their haploid genome and result in heritable differences in fitness), sperm heteromorphism and conjugation should be interpreted not as cooperation but rather as traits selected at the level of the male, much like other ejaculatory traits such as accessory gland proteins and ejaculate size.

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“…However, filamentous actin (F-actin) has been shown to be involved in this process in insects (Noguchi et al, 2003; Sahara and Kawamura, 2004). The potential role(s) of F-actin during spermiogenesis in mammals have been inferred from morphological studies, and include involvement in shaping the acrosome (Welch and O’Rand, 1985), attachment of the acrosome to the spermatid nucleus (Russell et al, 1986), and/or removal of cytoplasm during spermiation (Russell, 1979a; Russell, 1979b).…”

Section: Introductionmentioning

confidence: 99%

A missense mutation in the Capza3 gene and disruption of F-actin organization in spermatids of repro32 infertile male mice

Geyer

Inselman

Sunman

et al. 2009

Developmental Biology

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Males homozygous for the repro32 ENU-induced mutation produced by the Reproductive Genomics program at The Jackson Laboratory are infertile, have low epididymal sperm concentrations, and produce sperm with abnormally shaped heads and poor motility. The purpose of the present study was to identify the mutated gene in repro32 mice and to define the structural and functional changes causing infertility and the aberrant sperm phenotype. In repro32/repro32 mice, we discovered a failure to shed excess cytoplasm and disorganization of the middle piece of the flagellum at spermiation, resulting in the outer dense fibers being wrapped around the sperm head within a bag of cytoplasm. Using a candidate-gene approach, a mutation was identified in the spermatid-specific “capping protein (actin filament) muscle Z-line, alpha 3” gene (Capza3). CAPZA3 protein localization was altered in spermatids concurrent with altered localization of a unique CAPZB variant isoform and disruption of the filamentous actin (F-actin) network. These observations strongly suggest the missense mutation in Capza3 is responsible for the mutant phenotype of repro32/repro32 sperm and regulation of F-actin dynamics by a spermatogenic cell-specific CAPZ heterodimer is essential for removal of the cytoplasm and maintenance of midpiece integrity during spermiation in the mouse.

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Roles of actin networks in peristaltic squeezing of sperm bundles in Bombyx mori

Cited by 23 publications

References 12 publications

Actin-based dynamics during spermatogenesis and its significance

Actin-based dynamics during spermatogenesis and its significance

Evolution of intra-ejaculate sperm interactions: do sperm cooperate?

A missense mutation in the Capza3 gene and disruption of F-actin organization in spermatids of repro32 infertile male mice

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