RRC ID 46538
Author Yamamoto Y, Takeshita H, Sawa H.
Title Multiple Wnts redundantly control polarity orientation in Caenorhabditis elegans epithelial stem cells.
Journal PLoS Genet.
Abstract During development, cell polarization is often coordinated to harmonize tissue patterning and morphogenesis. However, how extrinsic signals synchronize cell polarization is not understood. In Caenorhabditis elegans, most mitotic cells are polarized along the anterior-posterior axis and divide asymmetrically. Although this process is regulated by a Wnt-signaling pathway, Wnts functioning in cell polarity have been demonstrated in only a few cells. We analyzed how Wnts control cell polarity, using compound Wnt mutants, including animals with mutations in all five Wnt genes. We found that somatic gonadal precursor cells (SGPs) are properly polarized and oriented in quintuple Wnt mutants, suggesting Wnts are dispensable for the SGPs' polarity, which instead requires signals from the germ cells. Thus, signals from the germ cells organize the C. elegans somatic gonad. In contrast, in compound but not single Wnt mutants, most of the six seam cells, V1-V6 (which are epithelial stem cells), retain their polarization, but their polar orientation becomes random, indicating that it is redundantly regulated by multiple Wnt genes. In contrast, in animals in which the functions of three Wnt receptors (LIN-17, MOM-5, and CAM-1) are disrupted--the stem cells are not polarized and divide symmetrically--suggesting that the Wnt receptors are essential for generating polarity and that they function even in the absence of Wnts. All the seam cells except V5 were polarized properly by a single Wnt gene expressed at the cell's anterior or posterior. The ectopic expression of posteriorly expressed Wnts in an anterior region and vice versa rescued polarity defects in compound Wnt mutants, raising two possibilities: one, Wnts permissively control the orientation of polarity; or two, Wnt functions are instructive, but which orientation they specify is determined by the cells that express them. Our results provide a paradigm for understanding how cell polarity is coordinated by extrinsic signals.
Volume 7(10)
Pages e1002308
Published 2011-10
DOI 10.1371/journal.pgen.1002308
PMID 22022276
PMC PMC3192832
MeSH Animals Body Patterning / genetics Caenorhabditis elegans / cytology* Caenorhabditis elegans / genetics Caenorhabditis elegans / growth & development Caenorhabditis elegans Proteins / genetics Caenorhabditis elegans Proteins / metabolism Cell Polarity / genetics* Cell Polarity / physiology DNA-Binding Proteins / genetics DNA-Binding Proteins / metabolism Epithelial Cells / cytology Epithelial Cells / physiology* Gene Expression Regulation, Developmental Germ Cells / physiology Glycoproteins / genetics Glycoproteins / metabolism Gonads / cytology Gonads / metabolism High Mobility Group Proteins / genetics High Mobility Group Proteins / metabolism Morphogenesis Mutant Proteins / genetics Mutant Proteins / metabolism Receptors, Wnt / genetics Receptors, Wnt / metabolism Stem Cells / cytology Stem Cells / physiology* Wnt Proteins / genetics Wnt Proteins / metabolism* Wnt Signaling Pathway / genetics
IF 5.54
Times Cited 16
C.elegans tm1422