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.