title: lin-12 and glp-1 are required zygotically for early embryonic cellular interactions and are regulated by maternal GLP-1 signaling in Caenorhabditis elegans.
abstract: Cell-cell interactions mediated by LIN-12 and GLP-1, members of the LNG (LIN-12, Notch, GLP-1) family of receptors, are required to specify numerous cell fates during development of the nematode Caenorhabditis elegans. Maternally expressed GLP-1 participates in two of at least four sequential inductive interactions that specify the fates of early embryonic descendants of the AB founder cell. We report that GLP-1 and LIN-12, and apparently their ligand, LAG-2, as well as a downstream component, LAG-1, are required in the latter two inductions. We find that LAG-2 is expressed in the signaling cells and LIN-12 is expressed in cells receiving the inductions, consistent with their proposed roles as ligand and receptor, respectively. Furthermore, we report that maternal GLP-1 activity is required (1) to repress early zygotic lag-2 expression and (2) to activate zygotic lin-12 expression in the early embryo. The patterning of both receptor and ligand expression by maternal GLP-1 signaling establishes competence for the zygotic LNG-mediated cellular interactions and localizes these interactions to the appropriate cells. We propose that activation of maternal GLP-1 regulates zygotic lin-12 and lag-2 expression by a regulatory mechanism analogous to that described for the post-embryonic gonad.
authors.affiliation: Department of Biochemistry, University of Wisconsin, Madison 53706, USA.
authors.forename: I P
authors.initials: IP
authors.lastname: Moskowitz
authors.forename: J H
authors.initials: JH
authors.lastname: Rothman
mesh_terms: D000818:Animals; D019521:Body Patterning; D017173:Caenorhabditis elegans / Q000196:embryology; D029742:Caenorhabditis elegans Proteins; D019070:Cell Lineage; D054407:Chemokine CCL4; D019742:Chemokines, CC; D002678:Chimera; D047108:Embryonic Development; D004627:Embryonic Induction; D005260:Female; D018507:Gene Expression Regulation, Developmental; D015801:Helminth Proteins / Q000378:metabolism*; D053685:Laser Therapy; D008024:Ligands; D019402:Macrophage Inflammatory Proteins; D008562:Membrane Glycoproteins / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D008954:Models, Biological; D011506:Proteins / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000378:metabolism*; D051880:Receptors, Notch; D015398:Signal Transduction; D015053:Zygote / Q000254:growth & development*
chemical_list: C066507:CCL4 protein, human; D029742:Caenorhabditis elegans Proteins; D054407:Chemokine CCL4; D019742:Chemokines, CC; C060620:Glp-1 protein, C elegans; D015801:Helminth Proteins; D008024:Ligands; C082460:Lin-12 protein, C elegans; D019402:Macrophage Inflammatory Proteins; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D011506:Proteins; D011956:Receptors, Cell Surface; D051880:Receptors, Notch; C086488:lag-2 protein, C elegans