Essential role of ADF/cofilin for assembly of contractile actin networks in the C. elegans somatic gonad

Kanako Ono, Sawako Yamashiro, Shoichiro Ono

    Research output: Contribution to journalArticlepeer-review

    30 Citations (Scopus)

    Abstract

    The somatic gonad of the nematode Caenorhabditis elegans contains a myoepithelial sheath, which surrounds oocytes and provides contractile forces during ovulation. Contractile apparatuses of the myoepithelial-sheath cells are non-striated and similar to those of smooth muscle. We report the identification of a specific isoform of actin depolymerizing factor (ADF)/cofilin as an essential factor for assembly of contractile actin networks in the gonadal myoepithelial sheath. Two ADF/cofilin isoforms, UNC-60A and UNC-60B, are expressed from the unc-60 gene by alternative splicing. RNA interference of UNC-60A caused disorganization of the actin networks in the myoepithelial sheath. UNC-60B, which is known to function in the body-wall muscle, was not necessary or sufficient for actin organization in the myoepithelial sheath. However, mutant forms of UNC-60B with reduced actin-filament-severing activity rescued the UNC-60A-depletion phenotype. UNC-60A has a much weaker filament-severing activity than UNC-60B, suggesting that an ADF/cofilin with weak severing activity is optimal for assembly of actin networks in the myoepithelial sheath. By contrast, strong actin-filament-severing activity of UNC-60B was required for assembly of striated myofibrils in the body-wall muscle. Our results suggest that an optimal level of actin-filament-severing activity of ADF/cofilin is required for assembly of actin networks in the somatic gonad.

    Original languageEnglish
    Pages (from-to)2662-2670
    Number of pages9
    JournalJournal of cell science
    Volume121
    Issue number16
    DOIs
    Publication statusPublished - 2008 Aug 15

    Keywords

    • Actin dynamics
    • Contraction
    • Myoepithelial cells
    • Ovulation
    • Severing

    ASJC Scopus subject areas

    • Cell Biology

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