title: The Caenorhabditis elegans gene mek-2 is required for vulval induction and encodes a protein similar to the protein kinase MEK.
abstract: An evolutionarily conserved signal transduction pathway that utilizes a receptor tyrosine kinase and a Ras protein mediates the induction of vulval cell fates in the nematode Caenorhabditis elegans. We sought new genes that function in this pathway by screening for suppressors of the Multivulva phenotype caused by a mutation that activates the let-60 ras gene. Seven such suppressor mutations defined a new gene involved in vulval induction. We named this gene mek-2, because its predicted protein product is most similar to MEK, a protein-serine/threonine and tyrosine kinase. mek-2 mutations can be arranged in an allelic series. A probable null mutation eliminated vulval induction, and the strongest mutations alter codons conserved in most or all protein kinases. Our genetic analysis showed that mek-2 functions downstream of let-60 ras and is required for ras-mediated signal transduction in vivo. The MEK-2 protein may interact with the products of the lin-45 raf and mpk-1 MAP kinase genes, which also mediate vulval induction.
authors.affiliation: Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge 02139, USA.
authors.forename: K
authors.initials: K
authors.lastname: Kornfeld
authors.forename: K L
authors.initials: KL
authors.lastname: Guan
authors.forename: H R
authors.initials: HR
authors.lastname: Horvitz
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D017173:Caenorhabditis elegans / Q000196:embryology / Q000235:genetics* / Q000378:metabolism; D029742:Caenorhabditis elegans Proteins; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D004627:Embryonic Induction; D005260:Female; D017238:Genes, Helminth / Q000235:genetics*; D005804:Genes, Lethal / Q000235:genetics; D048369:MAP Kinase Kinase 1; D048370:MAP Kinase Kinase 2; D019950:Mitogen-Activated Protein Kinase 1; D020929:Mitogen-Activated Protein Kinase Kinases; D008954:Models, Biological; D008969:Molecular Sequence Data; D016296:Mutagenesis; D017346:Protein Serine-Threonine Kinases / Q000235:genetics*; D011505:Protein-Tyrosine Kinases / Q000235:genetics*; D015398:Signal Transduction / Q000235:genetics*; D013489:Suppression, Genetic; D014844:Vulva / Q000196:embryology*; D018631:ras Proteins / Q000378:metabolism
chemical_list: D029742:Caenorhabditis elegans Proteins; D011505:Protein-Tyrosine Kinases; D017346:Protein Serine-Threonine Kinases; D019950:Mitogen-Activated Protein Kinase 1; C085697:mpk-1 protein, C elegans; D048369:MAP Kinase Kinase 1; D048370:MAP Kinase Kinase 2; D020929:Mitogen-Activated Protein Kinase Kinases; D018631:ras Proteins