The two actin-interacting protein 1 genes have overlapping and essential function for embryonic development in Caenorhabditis elegans

• Type of Material: Article
• Authors: Shoichiro Ono, Emory University; Kazumi Nomura, Emory University; Sadae Hitosugi, Emory University; Domena Tu, Simon Fraser University; Jocelyn A. Lee, Emory University; David Baillie, Simon Fraser University; Kanako Ono, Emory University
• Language: English
• Date: 2011-07-01
• Publisher: American Society for Cell Biology
• Publication Version: Final Published Version
• Copyright Statement: © 2011 Ono et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).
• License: Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported
• Final Published Version (URL): http://www.molbiolcell.org/content/22/13/2258
• Title of Journal or Parent Work: Molecular Biology of the Cell
• ISSN: 1059-1524
• Volume: 22
• Issue: 13
• Start Page: 2258
• End Page: 2269
• Grant/Funding Information: This work was supported by grants from the Natural Sciences and Engineering Research Council of Canada to D.L.B. and the National Institutes of Health (R01 AR48615) and University Research Committee of Emory University to S.O.
• Research Categories: Health Sciences, Pathology

Abstract

Disassembly of actin filaments by actin-depolymerizing factor (ADF)/cofilin and actin-interacting protein 1 (AIP1) is a conserved mechanism to promote reorganization of the actin cytoskeleton. We previously reported that unc-78, an AIP1 gene in the nematode Caenorhabditis elegans, is required for organized assembly of sarcomeric actin filaments in the body wall muscle. unc-78 functions in larval and adult muscle, and an unc-78–null mutant is homozygous viable and shows only weak phenotypes in embryos. Here we report that a second AIP1 gene, aipl-1 (AIP1-like gene-1), has overlapping function with unc-78, and that depletion of the two AIP1 isoforms causes embryonic lethality. A single aipl-1–null mutation did not cause a detectable phenotype. However, depletion of both unc-78 and aipl-1 arrested development at late embryonic stages due to severe disorganization of sarcomeric actin filaments in body wall muscle. In vitro, both AIPL-1 and UNC-78 preferentially cooperated with UNC-60B, a muscle-specific ADF/cofilin isoform, in actin filament disassembly but not with UNC-60A, a nonmuscle ADF/cofilin. AIPL-1 is expressed in embryonic muscle, and forced expression of AIPL-1 in adult muscle compensated for the function of UNC-78. Thus our results suggest that enhancement of actin filament disassembly by ADF/cofilin and AIP1 proteins is critical for embryogenesis.