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Genetics. Dec 1995; 141(4): 1365–1382.
PMCID: PMC1206873

Interacting Genes Required for Pharyngeal Excitation by Motor Neuron Mc in Caenorhabditis Elegans


We studied the control of pharyngeal excitation in Caenorhabditis elegans. By laser ablating subsets of the pharyngeal nervous system, we found that the MC neuron type is necessary and probably sufficient for rapid pharyngeal pumping. Electropharyngeograms showed that MC transmits excitatory postsynaptic potentials, suggesting that MC acts as a neurogenic pacemaker for pharyngeal pumping. Mutations in genes required for acetylcholine (ACh) release and an antagonist of the nicotinic ACh receptor (nAChR) reduced pumping rates, suggesting that a nAChR is required for MC transmission. To identify genes required for MC neurotransmission, we screened for mutations that cause slow pumping but no other defects. Mutations in two genes, eat-2 and eat-18, eliminated MC neurotransmission. A gain-of-function eat-18 mutation, ad820sd, and a putative loss-of-function eat-18 mutation, ad1110, both reduced the excitation of pharyngeal muscle in response to the nAChR agonists nicotine and carbachol, suggesting that eat-18 is required for the function of a pharyngeal nAChR. Fourteen recessive mutations in eat-2 fell into five complementation classes. We found allele-specific genetic interactions between eat-2 and eat-18 that correlated with complementation classes of eat-2. We propose that eat-18 and eat-2 function in a multisubunit protein complex involved in the function of a pharyngeal nAChR.

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Selected References

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  • Albertson DG, Thomson JN. The pharynx of Caenorhabditis elegans. Philos Trans R Soc Lond B Biol Sci. 1976 Aug 10;275(938):299–325. [PubMed]
  • Alfonso A, Grundahl K, Duerr JS, Han HP, Rand JB. The Caenorhabditis elegans unc-17 gene: a putative vesicular acetylcholine transporter. Science. 1993 Jul 30;261(5121):617–619. [PubMed]
  • Alfonso A, Grundahl K, McManus JR, Rand JB. Cloning and characterization of the choline acetyltransferase structural gene (cha-1) from C. elegans. J Neurosci. 1994 Apr;14(4):2290–2300. [PubMed]
  • Anderson P, Brenner S. A selection for myosin heavy chain mutants in the nematode Caenorhabditis elegans. Proc Natl Acad Sci U S A. 1984 Jul;81(14):4470–4474. [PMC free article] [PubMed]
  • Avery L. The genetics of feeding in Caenorhabditis elegans. Genetics. 1993 Apr;133(4):897–917. [PMC free article] [PubMed]
  • Avery L. Motor neuron M3 controls pharyngeal muscle relaxation timing in Caenorhabditis elegans. J Exp Biol. 1993 Feb;175:283–297. [PubMed]
  • Avery L, Horvitz HR. A cell that dies during wild-type C. elegans development can function as a neuron in a ced-3 mutant. Cell. 1987 Dec 24;51(6):1071–1078. [PMC free article] [PubMed]
  • Avery L, Horvitz HR. Pharyngeal pumping continues after laser killing of the pharyngeal nervous system of C. elegans. Neuron. 1989 Oct;3(4):473–485. [PubMed]
  • Avery L, Bargmann CI, Horvitz HR. The Caenorhabditis elegans unc-31 gene affects multiple nervous system-controlled functions. Genetics. 1993 Jun;134(2):455–464. [PMC free article] [PubMed]
  • Bargmann CI, Avery L. Laser killing of cells in Caenorhabditis elegans. Methods Cell Biol. 1995;48:225–250. [PubMed]
  • Boyer HW, Roulland-Dussoix D. A complementation analysis of the restriction and modification of DNA in Escherichia coli. J Mol Biol. 1969 May 14;41(3):459–472. [PubMed]
  • Brady ST. Molecular motors in the nervous system. Neuron. 1991 Oct;7(4):521–533. [PubMed]
  • Croll NA. Indolealkylamines in the coordination of nematode behavioral activities. Can J Zool. 1975 Jul;53(7):894–903. [PubMed]
  • Ferguson EL, Horvitz HR. Identification and characterization of 22 genes that affect the vulval cell lineages of the nematode Caenorhabditis elegans. Genetics. 1985 May;110(1):17–72. [PMC free article] [PubMed]
  • Fleming JT, Tornoe C, Riina HA, Coadwell J, Lewis JA, Sattelle DB. Acetylcholine receptor molecules of the nematode Caenorhabditis elegans. EXS. 1993;63:65–80. [PubMed]
  • Greenwald IS, Horvitz HR. unc-93(e1500): A behavioral mutant of Caenorhabditis elegans that defines a gene with a wild-type null phenotype. Genetics. 1980 Sep;96(1):147–164. [PMC free article] [PubMed]
  • Grillner S, Wallén P, Brodin L, Lansner A. Neuronal network generating locomotor behavior in lamprey: circuitry, transmitters, membrane properties, and simulation. Annu Rev Neurosci. 1991;14:169–199. [PubMed]
  • Harris-Warrick RM, Marder E. Modulation of neural networks for behavior. Annu Rev Neurosci. 1991;14:39–57. [PubMed]
  • Herman RK. Crossover suppressors and balanced recessive lethals in Caenorhabditis elegans. Genetics. 1978 Jan;88(1):49–65. [PMC free article] [PubMed]
  • Hodgkin J. Male Phenotypes and Mating Efficiency in CAENORHABDITIS ELEGANS. Genetics. 1983 Jan;103(1):43–64. [PMC free article] [PubMed]
  • Hodgkin J, Horvitz HR, Brenner S. Nondisjunction Mutants of the Nematode CAENORHABDITIS ELEGANS. Genetics. 1979 Jan;91(1):67–94. [PMC free article] [PubMed]
  • Horvitz HR, Brenner S, Hodgkin J, Herman RK. A uniform genetic nomenclature for the nematode Caenorhabditis elegans. Mol Gen Genet. 1979 Sep;175(2):129–133. [PubMed]
  • Horvitz HR, Chalfie M, Trent C, Sulston JE, Evans PD. Serotonin and octopamine in the nematode Caenorhabditis elegans. Science. 1982 May 28;216(4549):1012–1014. [PubMed]
  • Lewis JA, Wu CH, Berg H, Levine JH. The genetics of levamisole resistance in the nematode Caenorhabditis elegans. Genetics. 1980 Aug;95(4):905–928. [PMC free article] [PubMed]
  • McIntire SL, Jorgensen E, Horvitz HR. Genes required for GABA function in Caenorhabditis elegans. Nature. 1993 Jul 22;364(6435):334–337. [PubMed]
  • Miller JP, Selverston AI. Mechanisms underlying pattern generation in lobster stomatogastric ganglion as determined by selective inactivation of identified neurons. IV. Network properties of pyloric system. J Neurophysiol. 1982 Dec;48(6):1416–1432. [PubMed]
  • Nonet ML, Grundahl K, Meyer BJ, Rand JB. Synaptic function is impaired but not eliminated in C. elegans mutants lacking synaptotagmin. Cell. 1993 Jul 2;73(7):1291–1305. [PubMed]
  • Park EC, Horvitz HR. Mutations with dominant effects on the behavior and morphology of the nematode Caenorhabditis elegans. Genetics. 1986 Aug;113(4):821–852. [PMC free article] [PubMed]
  • Raizen DM, Avery L. Electrical activity and behavior in the pharynx of Caenorhabditis elegans. Neuron. 1994 Mar;12(3):483–495. [PubMed]
  • Stent GS, Kristan WB, Jr, Friesen WO, Ort CA, Poon M, Calabrese RL. Neuronal generation of the leech swimming movement. Science. 1978 Jun 23;200(4348):1348–1357. [PubMed]
  • Sulston JE, White JG. Regulation and cell autonomy during postembryonic development of Caenorhabditis elegans. Dev Biol. 1980 Aug;78(2):577–597. [PubMed]
  • Unwin N. The structure of ion channels in membranes of excitable cells. Neuron. 1989 Dec;3(6):665–676. [PubMed]
  • Verrall S, Hall ZW. The N-terminal domains of acetylcholine receptor subunits contain recognition signals for the initial steps of receptor assembly. Cell. 1992 Jan 10;68(1):23–31. [PubMed]
  • White JG, Southgate E, Thomson JN, Brenner S. The structure of the ventral nerve cord of Caenorhabditis elegans. Philos Trans R Soc Lond B Biol Sci. 1976 Aug 10;275(938):327–348. [PubMed]
  • Wu CF, Ganetzky B. Neurogenetic studies of ion channels in Drosophila. Ion Channels. 1992;3:261–314. [PubMed]
  • Zabin I, Villarejo MR. Protein complementation. Annu Rev Biochem. 1975;44:295–313. [PubMed]
  • Zengel JM, Epstein HF. Identification of genetic elements associated with muscle structure in the nematode Caenorhabditis elegans. Cell Motil. 1980;1(1):73–97. [PubMed]

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