Worm Breeder's Gazette 10(2): 129

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.

Characterisation and Cloning of unc-24

William Nawrocki, Eileen Southgate and J. Nichol Thomson

The behavioral phenotype of unc-24 worms is characterized by 
severely kinked L1 worms that do not wriggle more than one quarter 
body length in either forward or backward directions, whereas worms 
from the L2 stage onward toward adults are only slightly kinked in 
motion and make progress similar to N2 worms.  These observations 
appear to indicate that the unc-24 gene may be affecting the embryonic 
motoneurones (DAs, DBs and DDs).
Reconstruction of three different alleles of unc-24 have not been 
consistent.  The canonical allele (e138) reconstruction shows DA 
motoneurones to be lacking commissures to the dorsal musculature.  A 
Tc1 allele (e2386) reconstruction contains one DA motoneurone with the 
same aberration but another with normal morphology.  The P32 induced 
allele (e927) reconstruction presents DA motoneurones with normal 
morphologies, but the commissures of all D motoneurones (DAs, DBs and 
DDs) proceed toward the dorsal cord on the opposite side to the wild 
type condition.  To clear up this ambiguity, a reconstruction of an L1 
from, the canonical strain is being completed.
The unc-24 gene has been isolated.  A 5.6kb BamHI Tc1 containing 
fragment found in an allele (e2386) isolated from the TR679 strain 
that also shifts to a 4.0kb BamHI fragment in revertants and Bristol 
strains was cloned into pUC 8.  A 1.0kb non-Tc1 containing fragment 
was isolated from this plasmid by BamHI and EcoRV digestion and was 
used as a probe to screen the Coulson and Sulston cosmid library.  Two 
true positives were identified that mapped to a contig containing the 
vit-6 gene on linkage group IV.  Fortunately, a larger cosmid in this 
contig which covered both newly identified cosmids had been used as an 
in situ hybridization probe by Rita Fishpool and Donna Albertson and 
showed binding to chromosome IV.  The same 1.0kb non-Tc1 fragment was 
used to isolate 16 lambda clones from the 2a cDNA library of Julie 
Ahringer.  The lambda inserts range in size from 0.6kb to 2.6kb.  The 
largest of these was used as a probe and showed polymorphic band 
shifts on the genomic Southerns composed of different alleles of unc-
24.  This insert is being sequenced.