Mosaic Analysis of Two Genes That Affect Nervous System Structure in Caenorhabditis elegans

Robert K. Herman ¹

¹ Department of Genetics and Cell Biology, University of Minnesota, St. Paul, Minnesota 55108

The mutation mec-4(e1611), identified by M. Chalfie, leads to the degeneration and death of the six neurons, called the microtubule cells, that mediate the response of wild-type animals to light touch. The fates of two of these cells, PLML and PLMR, which are responsible for response to light touch in the tail of the animal, have been monitored in animals mosaic for the mec-4(e1611) mutation. The results are consistent with the view that the mutation behaves cell autonomously in its killing effect; in particular, none of the neurons that make either chemical synapses or gap junctions to PLML or PLMR is responsible for the deaths of PLML or PLMR. The results of gene dosage and dominance tests suggest that the mec-4(+) gene product, which is required for wild-type microtubule cell function, is altered by the e1611 mutation into a novel product that kills the microtubule cells. Mutation in the gene unc-3 leads to the derangement of the processes of the motor neurons of the ventral cord. Mosaic analysis strongly suggests that unc-3(+) expression is required only in the motor neurons themselves for normal neuronal development. In particular, the hypodermis surrounding the ventral cord is not the primary focus of unc-3 action (body muscle was excluded in earlier work). Finally, the mosaic analysis supports an earlier suggestion that a sensory defect caused by a daf-6 mutation is localized to a non-neuronal cell called the sheath cell.

This article has been cited by other articles:

				V. Ambros The 2007 George W. Beadle Medal Genetics, February 1, 2007; 175(2): 465 - 466. [Full Text] [PDF]

				D. C. Royal, L. Bianchi, M. A. Royal, M. Lizzio Jr., G. Mukherjee, Y. O. Nunez, and M. Driscoll Temperature-sensitive Mutant of the Caenorhabditis elegans Neurotoxic MEC-4(d) DEG/ENaC Channel Identifies a Site Required for Trafficking or Surface Maintenance J. Biol. Chem., December 23, 2005; 280(51): 41976 - 41986. [Abstract] [Full Text] [PDF]

				P. Syntichaki and N. Tavernarakis Genetic Models of Mechanotransduction: The Nematode Caenorhabditis elegans Physiol Rev, October 1, 2004; 84(4): 1097 - 1153. [Abstract] [Full Text] [PDF]

				M. Ailion and J. H. Thomas Dauer Formation Induced by High Temperatures in Caenorhabditis elegans Genetics, November 1, 2000; 156(3): 1047 - 1067. [Abstract] [Full Text]

				E. Peckol, J. Zallen, J. Yarrow, and C. Bargmann Sensory activity affects sensory axon development in C. elegans Development, January 5, 1999; 126(9): 1891 - 1902. [Abstract] [PDF]

				B. Prasad, B Ye, R Zackhary, K Schrader, G Seydoux, and R. Reed unc-3, a gene required for axonal guidance in Caenorhabditis elegans, encodes a member of the O/E family of transcription factors Development, January 4, 1998; 125(8): 1561 - 1568. [Abstract] [PDF]

				S. S. Wang, R. Y. L. Tsai, and R. R. Reed The Characterization of the Olf-1/EBF-Like HLH Transcription Factor Family: Implications in Olfactory Gene Regulation and Neuronal Development J. Neurosci., June 1, 1997; 17(11): 4149 - 4158. [Abstract] [Full Text] [PDF]

				J. Garcia-Anoveros, B. Derfler, J. Neville-Golden, B. T. Hyman, and D. P. Corey BNaC1 and BNaC2 constitute a new family of human neuronal sodium channels related to degenerins and epithelial sodium channels PNAS, February 18, 1997; 94(4): 1459 - 1464. [Abstract] [Full Text] [PDF]

				D. H. Hall, G. Gu, J. Garcia-Anoveros, L. Gong, M. Chalfie, and M. Driscoll Neuropathology of Degenerative Cell Death in Caenorhabditis elegans J. Neurosci., February 1, 1997; 17(3): 1033 - 1045. [Abstract] [Full Text] [PDF]

				B Wightman, R Baran, and G Garriga Genes that guide growth cones along the C. elegans ventral nerve cord Development, January 7, 1997; 124(13): 2571 - 2580. [Abstract] [PDF]

				Y Jia, G Xie, J. McDermott, and E Aamodt The C. elegans gene pag-3 is homologous to the zinc finger proto-oncogene gfi-1 Development, January 5, 1997; 124(10): 2063 - 2073. [Abstract] [PDF]

				J C Way and M Chalfie The mec-3 gene of Caenorhabditis elegans requires its own product for maintained expression and is expressed in three neuronal cell types. Genes & Dev., December 1, 1989; 3(12a): 1823 - 1833. [Abstract] [PDF]

				A D Chisholm and J Hodgkin The mab-9 gene controls the fate of B, the major male-specific blast cell in the tail region of Caenorhabditis elegans. Genes & Dev., September 1, 1989; 3(9): 1413 - 1423. [Abstract] [PDF]