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Review
. 2020 Nov 12;69(4):374-381.
doi: 10.1538/expanim.20-0064. Epub 2020 Jun 18.

Analysis of the sperm flagellar axoneme using gene-modified mice

Affiliations
Review

Analysis of the sperm flagellar axoneme using gene-modified mice

Haruhiko Miyata et al. Exp Anim. .

Abstract

Infertility is a global health issue that affects 1 in 6 couples, with male factors contributing to 50% of cases. The flagellar axoneme is a motility apparatus of spermatozoa, and disruption of its structure or function could lead to male infertility. The axoneme consists of a "9+2" structure that contains a central pair of two singlet microtubules surrounded by nine doublet microtubules, in addition to several macromolecular complexes such as dynein arms, radial spokes, and nexin-dynein regulatory complexes. Molecular components of the flagellar axoneme are evolutionally conserved from unicellular flagellates to mammals, including mice. Although knockout (KO) mice have been generated to understand their function in the formation and motility regulation of sperm flagella, the majority of KO mice die before sexual maturation due to impaired ciliary motility, which makes it challenging to analyze mature spermatozoa. In this review, we introduce methods that have been used to overcome premature lethality, focusing on KO mouse lines of central pair components.

Keywords: central pair; chimeric mice; male fertility.

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Figures

Fig. 1.
Fig. 1.
Mouse sperm flagellum. Flagella can be divided into three parts: the midpiece, principal piece, and endpiece. Cross sections of each part are shown. The axoneme runs through the flagellum, which consists of several macromolecular complexes. CP, central pair; DMT, doublet microtubules; IDA, inner dynein arm; N-DRC, nexin-dynein regulatory complex; ODA, outer dynein arm; RS, radial spoke.
Fig. 2.
Fig. 2.
Structure and components of the CP. There are two singlet microtubules, C1 and C2, that contain several projections (C1a-C1f and C2a-C2e). There is also a bridge that connects C1 and C2 microtubules. Chlamydomonas CP components (top) with mouse orthologs (bottom) are indicated.
Fig. 3.
Fig. 3.
Chimeric analysis. A gene of interest is knocked out in ES cells that express fluorescent proteins. Chimeric mice are generated with the ES cells, and phenotypes of KO cells that are derived from ES cells are analyzed, such as spermatozoa or blood cells, using the fluorescence as a marker. Because chimeric mice possess wild-type cells derived from host embryos, the mice could overcome premature lethality.

References

    1. Abbasi F., Miyata H., Ikawa M.2017. Revolutionizing male fertility factor research in mice by using the genome editing tool CRISPR/Cas9. Reprod. Med. Biol. 17: 3–10. doi: 10.1002/rmb2.12067 - DOI - PMC - PubMed
    1. Abbasi F., Miyata H., Shimada K., Morohoshi A., Nozawa K., Matsumura T., Xu Z., Pratiwi P., Ikawa M.2018. RSPH6A is required for sperm flagellum formation and male fertility in mice. J. Cell Sci. 131: jcs221648. doi: 10.1242/jcs.221648 - DOI - PMC - PubMed
    1. Bernstein M., Beech P.L., Katz S.G., Rosenbaum J.L.1994. A new kinesin-like protein (Klp1) localized to a single microtubule of the Chlamydomonas flagellum. J. Cell Biol. 125: 1313–1326. doi: 10.1083/jcb.125.6.1313 - DOI - PMC - PubMed
    1. Bisgrove B.W., Yost H.J.2006. The roles of cilia in developmental disorders and disease. Development 133: 4131–4143. doi: 10.1242/dev.02595 - DOI - PubMed
    1. Brown J.M., Dipetrillo C.G., Smith E.F., Witman G.B.2012. A FAP46 mutant provides new insights into the function and assembly of the C1d complex of the ciliary central apparatus. J. Cell Sci. 125: 3904–3913. doi: 10.1242/jcs.107151 - DOI - PMC - PubMed