Worm Breeder's Gazette 13(4): 59 (October 1, 1994)

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.

Progress on unc-119.

Morris Maduro, David Pilgrim

Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada

Figure 1

  unc-119 mutant animals are strongly uncoordinated and capable of only little
head movement. Transverse electron micrographs of body-wall muscle show no
ultrastructural defects in assembly or attachment. Polarized light and antibody
staining with anti-vinculin show that muscle is normal; animals also hypercontract
in the presence of levamisole. The basis for the unc phenotype is apparently
presynaptic. (Thanks to Mary Gilbert and the Moerman lab for help.)
  eDf2 ; eDp6 ,a strain homozygous for a break/gap in LGIII, has a phenotype
similar to unc-119 ( e2498 ).We had previously located the breakpoint of eDf2 relative to
the physical map (WBG 13(2) and have since located the breakpoint of eDp6 .Both
breakpoints are contained on M142 ,a cosmid recently placed on the physical map.
This cosmid rescues the unc phenotype of unc-119 ( e2498 )as well as eDf2 ; eDp6 .
M142 also rescues vab-7 (J. Ahringer, WBG 13(2), which maps less than 0.1 m.u. to
the right of unc-119 and is complemented by eDp6 .
  The smallest rescuing subclone, DP#MM019 ,does not cross-hybridize to
Southern blots of eDf2 ; eDp6 DNA. Only 8 kbp are deleted, so it is likely that unc-119 is
the only gene missing in this strain. DP#MM019 was used to screen the Barstead
cDNA library. Three clones were pulled out, one of which appears to be full-length at
980 bp. Two of the three cDNAs contain 5' ends that extend beyond the rescuing
fragment. Rescue may occur because of an in-frame ATG at the beginning of the
third exon (shown in lower case), which lies just inside DP#MM019 .The sequence of
the upstream genomic region has not yet been completely determined, so it is possible
that the first exon is further to the left. The Tc1 element in e2498 is located in exon IV.
The first ATG does not appear to be used since there are stop codons in all frames just
upstream of the ORF. The three stop codons are preceded by a region that is 84% A=T
over 37 base pairs, so this part does not appear to be coding. The ~220 a.a. ORF
(shown shaded) predicts a protein that has no significant similarity to others in the
databases. (Thanks to Richard Durbin for sequence information in the region.) A
lambda Ch aron4 clone of C. briggsae also rescues unc-119 ,so this gene is
functionally conserved between the two species. This clone cross-hybridizes the cDNA
at low stringency.(see figure)

Figure 1