Worm Breeder's Gazette 11(4): 16
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.
In the previous gazette (WBG: 11 (3), p69), we have described isolation of axon growth mutants using the FITC dye staining method of Hedgecock et al. (1985), in the mutator strain RW7097. In particular we mentioned a strain SQ141, that lacked staining of phasmid neurons PHA and PHB in the adult hermaphrodites. This mutation has been mapped on linkage group IV close to dpy-13, prompting us to complement SQ141 mutation with osm-3 and osm-4 (aka daf-10) that were reported lacking FITC staining of PHA and PHB neurons (Perkins et al. 1986). SQ141 complements osm-4(aka daf-10), but it does not complement osm-3( p802) allele. However, the osm-3(p802) phenotype, is different from the reported description of the osm-3(p802) in that we find about 35% hermaphrodites show weak staining of one or two pairs of amphid neurons. The phasmid neurons in osm-3(p802) adult hermaphrodites do not stain; but about 26% osm-3(p802) males show staining of the phasmid neurons. We also observe weak staining of one or two pairs of amphid neurons in about 60% osm-3(p802) males. We have isolated another strain SQ160, from RW7097, that fails to complement the phasmid phenotype of SQ141 and osm-3(p802) in adult hermaphrodites. For complementation studies, we have only considered the PHA and PHB staining pattern in the adult hermaphrodites, in appropriately marked crosses to distinguish the self progeny from the cross progeny, as the FITC staining of PHA and PHB in males can not be used to score complementation two factor cross data between osm-3 and dpy-13 places the two mutations 2.2% apart (dpy-13(e184) 5/110 SQ141). The osm-3 mutations in SQ141 and SQ160 strains have been backcrossed with N2 males ten times, to recover these mutations in Bristol background using appropriate recombinant strains with osm-3 and dpy-13, and osm-3 and unc-17, we find a 3.9 kb band on Southerns of DNA isolated from different strains, with a Tc1 probe, that is associated with the osm-3 mutation, and is absent in strains lacking the osm-3 alleles. Experiments are in progress to further characterize and clone the osm-3 specific DNA band. Mutants in osm-3 were first isolated by Joe Culotti and Richard Russell (1978), by a simple behavioral assay in which these chemosensory mutants fail to avoid high (4M) concentrations of NaCl; and were later tested for a variety of behaviors (Perkins et al. 1986) . We have performed these assays on SQ141 and SQ160 animals, and their behaviors are typical of other osm-3 alleles