title: The sys-1 and sys-3 genes cooperate with Wnt signaling to establish the proximal-distal axis of the Caenorhabditis elegans gonad.
abstract: To form the proximal-distal axis of the C. elegans gonad, two somatic gonadal precursor cells, Z1 and Z4, divide asymmetrically to generate one daughter with a proximal fate and one with a distal fate. Genes governing this process include the lin-17 frizzled receptor, wrm-1/beta-catenin, the pop-1/TCF transcription factor, lit-1/nemo-like kinase, and the sys-1 gene. Normally, all of these regulators promote the distal fate. Here we show that nuclear levels of a pop-1 GFP fusion protein are less abundant in the distal than in the proximal Z1/Z4 daughters. This POP-1 asymmetry is lost in mutants disrupting Wnt/MAPK regulation, but retained in sys-1 mutants. We find that sys-1 is haplo-insufficient for gonadogenesis defects and that sys-1 and pop-1 mutants display a strong genetic interaction in double heterozygotes. Therefore, sys-1 is a dose-sensitive locus and may function together with pop-1 to control Z1/Z4 asymmetry. To identify other regulatory genes in this process, we screened for mutants resembling sys-1. Four such genes were identified (gon-14, -15, -16, and sys-3) and shown to interact genetically with sys-1. However, only sys-3 promotes the distal fate at the expense of the proximal fate. We suggest that sys-3 is a new key gene in this pathway and that gon-14, gon-15, and gon-16 may cooperate with POP-1 and SYS-1 at multiple stages of gonad development.
authors.affiliation: Laboratory of Genetics, University of Wisconsin, Madison, Wisconsin 53706-1544, USA.
authors.forename: Kellee R
authors.initials: KR
authors.lastname: Siegfried
authors.forename: Ambrose R
authors.initials: AR
authors.lastname: Kidd
authors.forename: Michael A
authors.initials: MA
authors.lastname: Chesney
authors.forename: Judith
authors.initials: J
authors.lastname: Kimble
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D001483:Base Sequence; D019521:Body Patterning / Q000235:genetics; D017173:Caenorhabditis elegans / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism; D018509:DNA, Helminth / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D005260:Female; D018507:Gene Expression Regulation, Developmental; D017238:Genes, Helminth; D006066:Gonads / Q000254:growth & development / Q000378:metabolism; D006609:High Mobility Group Proteins / Q000235:genetics / Q000378:metabolism; D020935:MAP Kinase Signaling System; D008297:Male; D008954:Models, Biological; D009154:Mutation; D010641:Phenotype; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D051153:Wnt Proteins
chemical_list: D029742:Caenorhabditis elegans Proteins; D018509:DNA, Helminth; D004268:DNA-Binding Proteins; D006609:High Mobility Group Proteins; D011518:Proto-Oncogene Proteins; D011993:Recombinant Fusion Proteins; D051153:Wnt Proteins; C096787:pop-1 protein, C elegans