Worm Breeder's Gazette 8(3): 82

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 Toward the Cloning of unc-105 and rol-6

J. Park, K. Edwards, R. Horvitz

Figure 1

We are attempting to clone unc-105 and rol-6, both of which have 
been established to have wild-type null phenotypes.  By repeated 
genetic backcrosses, we have constructed strains almost entirely 
derived from the C.  elegans Bristol strain except for a small region 
of Bergerac chromosome II corresponding to the region to which both 
unc-105 and rol-6 have been mapped.  We have localized 29 Bergerac-
derived Tc1 elements within this region and have cloned in phage 
lambda-gt7 seven that map close to unc-105 and rol-6.We have mapped 
the four clones closest to unc-105 and rol-6 with respect to a series 
of LGII deficiencies.  (Deficiency strains and the deficiency map 
shown below have been kindly provided to us by Chris Sigurdson and Bob 
Herman.  The distance represented on this map corresponds to about two 
genetic map units, which we estimate to be approximately 600 kb of DNA.
) These clones were localized by Southern hybridization experiments 
using DNA isolated from Bristol strains heterozygous for different 
deficiencies and using the phage clones as probes.  Strains of 
genotype mnDf unc-4/C1 unc-52 were grown on 
agarose plates for a number of generations, and DNA was isolated from 
the population of animals present, i.e., from a mixture of deficiency 
homozygotes (dead eggs and/or dead larvae), wild types and C1 
homozygotes.  Since C1 homozygotes are sterile and deficiency 
homozygotes are inviable, we assume that both LGII chromosomes are 
represented approximately equally in the DNA preparations.  We have 
probed DNA both from N2 and from different deficiency strains with our 
phage clones.  In each case, Southern hybridization experiments have 
revealed one novel band in addition to those Tc1-containing bands 
normally seen in Bristol strains; this novel band presumably 
corresponds to the unique sequence DNA surrounding the Tc1 element in 
the cloned probe.  For cases in which the DNA of a deficiency strain 
resulted in this band's being of reduced intensity relative to the Tc1-
containing bands (and compared to a lane containing N2 DNA), we 
concluded that the clone used as a probe mapped within that deficiency.
The map locations of four of our clones are shown below.
[See Figure 1]

Figure 1