Wnt signaling polarizes an early C. elegans blastomere to distinguish endoderm from mesoderm.
A polarizing signal induces endoderm production by a 4-cell stage blastomere in C. elegans called EMS. We identified 16 mutations in five genes, mom-1 through mom-5, required for EMS to produce endoderm. mom-1, mom-2, and mom-3 are required in the signaling cell, P2, while mom-4 is required in EMS. P2 signaling downregulates an HMG domain protein, POP-1, in one EMS daughter. The sequence of mom-2 predicts that it encodes a member of the Wnt family of secreted glycoproteins, which in other systems activate HMG domain proteins. Defective mitotic spindle orientations in mom mutant embryos indicate that Wnt signaling influences cytoskeletal polarity in blastomeres throughout the early embryo.
Thorpe
C J
CJ
Institute of Molecular Biology, University of Oregon, Eugene 97403, USA.
Schlesinger
A
A
Carter
J C
JC
Bowerman
B
B
D000483:Alleles; D000818:Animals; D001757:Blastomeres / Q000166:cytology*; D017173:Caenorhabditis elegans / Q000196:embryology* / Q000235:genetics; D029742:Caenorhabditis elegans Proteins; D016764:Cell Polarity; D004268:DNA-Binding Proteins / Q000378:metabolism; D015536:Down-Regulation; D004627:Embryonic Induction / Q000235:genetics*; D004707:Endoderm / Q000166:cytology*; D017238:Genes, Helminth; D006023:Glycoproteins / Q000378:metabolism; D015801:Helminth Proteins / Q000235:genetics* / Q000502:physiology; D006609:High Mobility Group Proteins / Q000378:metabolism; D008648:Mesoderm / Q000166:cytology*; D009154:Mutation; D015398:Signal Transduction; D008941:Spindle Apparatus / Q000235:genetics; D014157:Transcription Factors / Q000378:metabolism
D029742:Caenorhabditis elegans Proteins; D004268:DNA-Binding Proteins; D006023:Glycoproteins; D015801:Helminth Proteins; D006609:High Mobility Group Proteins; D014157:Transcription Factors; C096787:pop-1 protein, C elegans