Worm Breeder's Gazette 11(5): 98

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.

unc-120 Another Gene with Effects on Muscle

Ian M. Caldicott and Robert H. Waterston

We have been working on the mutant unc-120(st364ts).  unc-120(st364) 
moves slowly at 15 C, shows degrees of paralysis ranging from very 
slow movement to complete paralysis at 20 C and complete paralysis at 
25 C.  The animals at 25 C are also sterile.  The sterility is caused 
by a germ line defect that is highly variable at other temperatures 
and may yet be due to another tightly linked mutation.  Analysis with 
polarized light, myosin antibodies and phalloidin staining shows that 
the body wall muscle is well organized except for a reduced number of 
birefringent/staining bands.  The number of bands observed varies from 
cell to cell and animal to animal.  At 15 C the number of bands per 
cell varies from 10 to 7 in the body wall cells at 1/3 body length and 
at 20 C band number varies from 5 to 9 in the same region.  Wild type 
muscle has 9-10 (usually 10) bands per cell in the same region.
Three factor mapping has placed unc-120 between daf-8 and lin-10 in 
the cluster on chromosome I from the following experiments.  dpy non 
unc recombinants were picked from the strain dpy-5 lin-10 with the following result dpy-5 (70/81) lin-
10 (11/81) unc-120.   lin non daf recombinants were picked from the 
strain lin-10 -120 with the following result lin-10 (
9/21) unc-120 (12/21) daf-8.   Fortuitously Paul Mains had been 
constructing strains with cosmids from the region while trying to 
rescue mei-1.  Unfortunately for Paul but fortunately for us he tried 
cosmids spanning almost the entire region before finding one that 
rescued (Clark-Maguire and Mains WBG 11(4)).  We obtained Paul's 
strains and conducted crosses to see if we could get rescue.  The 
strains were constructed by coinjecting the cosmids with rol-6 (as a 
marker) to generate arrays, but had not been tested for the presence 
of the cosmid in the constructs.  Strain HR50 containing the cosmid 
C48B1 was found to rescue unc-120(st364ts) (but not the germ line 
defect ) however strains injected with the adjacent cosmids C05D8 and 
C26C7 did not rescue.  Cosmids C05D8 and C26C7 overlap on the physical 
map by 1-2 HindIII sites.
The three cosmids have been obtained from Cambridge and we plan to 
use them to refine the physical position of unc-120 and then sequence 
the gene.  A preliminary screen for new alleles has failed to provide 
any new alleles, but more extensive screens are now being undertaken.