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.

Molecular Cloning of osm-3 Gene by Transposon Tagging

M.A. Shakir and Shahid Siddiqui

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