Worm Breeder's Gazette 11(3): 69
These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.
We have previously described (WBG:ll (2), p59) our attempts to isolate axon growth mutants of C. elegans using dye filling ( Hedgecock, E. et al. 1985), or immunocytochemical staining (Siddiqui, S. et al. 1989) screening of the mutator strains RW7097 and TR679. In particular we are interested in mutations affecting the development of the lumbar neurons (PHA, PHB, PHC, PVN, PLM, and PVR). Several putative mutants affecting lumbar neurons have been isolated in such screens and are being genetically mapped. In one of the mutant isolates, SQ141, phasmid neurons PHA and PHB fail to stain with fluorescein dyes in adult hermaphrodites. We do observe faint staining of phasmid neurons in the young larvae of SQ141 (pointed out to us by E. Hedgecock on his visit to Toyohashi). However, more interestingly, we find that 60% SQ141 males apparently show the staining of phasmid neurons. The intensity of PHA and PHB staining in SQ141 males is less than that of the wild type. Similarly, in 64% stained SQ141 males, amphid neurons are stained with FITC. This staining is limited to one or two pairs of the amphid neurons, and is less intense than the staining of the wild type amphid neurons. Also,in 30-35% SQ141 adult hermaphrodites; one or two pairs of the amphid neurons stain with FITC. We have mapped it on linkage group IV, close to dpy-13(e184) IV, and are in the process of complementing with mutants on IV chromosome that lack staining of chemosensory neurons when stained with FITC dye. These include osm-3 and osm-4(daf-10);(Perkins, et al. 1986). SQ141 animals are defective in osmotic avoidance, and show reduced chemotaxis to NaCl. However, SQ141 phenotypes do not strictly correspond to osm-3, since osm-3 is reported to show complete lack of staining of the amphid and phasmid neurons, whereas, SQ141 amphids partially stain. On the other hand osm-4 (or daf-10), mutant animals show partial staining of the amphid neurons, and osm-4 males do not mate. However SQ141 males, are fertile, and mate with high efficiency. The mechanosensitivity of SQ141 animals is normal. SQ141 strain has now been backcrossed ten times with N2 males, and Tc1 distribution pattern analysis on Southern blots is in progress. We will appreciate receiving behavioral mutants of C. elegans isolated in the mutator strain background.