Worm Breeder's Gazette 14(2): 80 (February 1, 1996)

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.

dv52: A New Neuronal Unc?

Shale Dames, Chris Link

University of Denver, Denver, CO. 80208

        We have characterized a novel mutant, dv52,  that maps to the
right arm of Linkage Group IV between unc-24 and dpy-4, approximately
1.0 map unit to the left of dpy-4.  dv52 is complemented by sDf21,
sDf23, and sDf60, but not nDf27.  dv52 was originally isolated in an EMS
mutagenesis screen while searching for coiler-Unc animals in a srf-5
background.  srf-5 is a non-pleiotropic Srf mutant that binds both
soybean and wheat germ agglutinin on the cuticle.  In addition to its
Unc phenotype, dv52 suppresses the ectopic lectin-binding phenotype of
srf-5.  We are particularly interested in such supressors, as they are
candidates for mutants that are defective in glycosylation.

        The coiler-Unc phenotype of dv52 is similar to unc-17 and is
completely penetrant, but with variable expressivity.  Severe mutants
display a tightly-coiled "cinnamon role" phenotype, whereas the least
severe animals have an "omega-shaped" appearance.  All dv52's possess a
"J-tail" phenotype that is insensitive to tail prodding.  dv52  has a
mating efficiency of 0, and is slightly smaller than N2.

        We looked at the DD and VD neurons (among others) using
anti-GABA antibody and integrated transgenic reporter constructs
containing either an unc-5/GFP (KP762) or unc-119/GFP (DP86) fusion
(altruistically donated by L. Ryder/J. Culotti and M. Madurro,
respectively).  We found that dv52 possesses incomplete and/or abnormal
DD4/VD8 and DD5/VD10 commissures compared with N2 and srf-5.  Below are
results from the anti-GABA experiments scoring approximately 2,500
commissures (note that some dv52 animals have defects in both sets of
commissure pairs):

Genotype  N           abnormal DD4/VD8        abnormal DD5/VD10
N2        50              0 (0%)                     1 (2%)
srf-5     100             6 (6%)                     6 (6%)
dv52      92             25 (27%)                   81 (88%)

The unc-5/GFP data supports the GABA data (30/30 dv52 animals have
defects with the DD5/VD10 neurons).

        dv52 complements all known Uncs on LG IV.  The phenotype of
dv52/nDf27 animals appears the same as homozygous dv52 males, suggesting
that dv52 could be a null allele.  However, we have been unable to
recover new alleles despite repeated F2 screens (approximately 70,000
animals screened) or non-complementation screens (approximately 3,300
animals screened).