The nonmuscle myosin regulatory light chain gene mlc-4 is required for cytokinesis, anterior-posterior polarity, and body morphology during Caenorhabditis elegans embryogenesis. |
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Authors: | C A Shelton J C Carter G C Ellis B Bowerman |
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Institution: | Institute of Molecular Biology, University of Oregon, Eugene, Oregon 97403-1229, USA. |
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Abstract: | Using RNA-mediated genetic interference in a phenotypic screen, we identified a conserved nonmuscle myosin II regulatory light chain gene in Caenorhabditis elegans, which we name mlc-4. Maternally supplied mlc-4 function is required for cytokinesis during both meiosis and mitosis and for establishment of anterior-posterior (a-p) asymmetries after fertilization. Reducing the function of mlc-4 or nmy-2, a nonmuscle myosin II gene, also leads to a loss of polarized cytoplasmic flow in the C. elegans zygote, supporting models in which cytoplasmic flow may be required to establish a-p differences. Germline P granule localization at the time of cytoplasmic flow is also lost in these embryos, although P granules do become localized to the posterior pole after the first mitosis. This result suggests that a mechanism other than cytoplasmic flow or mlc-4/nmy-2 activity can generate some a-p asymmetries in the C. elegans zygote. By isolating a deletion allele, we show that removing zygotic mlc-4 function results in an elongation phenotype during embryogenesis. An mlc-4/green fluorescent protein transgene is expressed in lateral rows of hypodermal cells and these cells fail to properly change shape in mlc-4 mutant animals during elongation. |
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Keywords: | microfilament proteins RNA-mediated interference nonmuscle myosin II regulatory light chain P granules morphogenesis |
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