Program of the 2001 International Worm Meeting - Sternberg Lab ...

928
Localized expression of an UNC-119::GFP
fusion protein in neural subsets rescues the
neural defects only in the cells in which it is
expressed. Ectopic expression in muscles does
not rescue any structural or behavioral defects.
Thus UNC-119 acts cell-autonomously. The rat
homologue, RRG4, has been shown to be
associated with synaptic vesicles of
photoreceptor ribbon synapses. We have raised
antibodies to amino, middle and carboxyl
portions of UNC-119 and will describe
localization of the protein the worm.
929. Neuronal Defects Elicited by
Ectopic Expression of C. elegans
Kallmann Protein
Katherine L. Berry, Hannes E.
Bülow, Oliver Hobert
929
Columbia University, College of Physicians and
Surgeons, Dept. Biochemistry, New York 10032
The Kallmann Syndrome gene, KAL-1, codes
for a cell surface protein containing a protease
inhibitor domain and three FNIII repeats.
Mutations in this gene cause defects in axon
targeting in the olfactory system of humans. The
C. elegans ortholog, Cekal-1, shows high
structural homology to human KAL-1 and is
expressed in a subset of C. elegans neurons as
well as in the excretory canal and uterine lumen
(1). To investigate potential effects of Cekal-1
on the nervous system of C. elegans, we
ectopically expressed the gene under a variety
of neuron specific promoters.
Ectopic expression of CeKAL-1 in either the
AFD thermosensory neuron or the AIY
interneuron causes a cell-autonomous, highly
penetrant, protein-specific neurite sprouting
defect (1). A modifier screen of the sprouting
defect in AIY yielded seven modifier mutants in
five complementation groups; these mutants
either suppressed or qualitatively enhanced the
sprouting phenotype and only modified neurites
generated by CeKAL-1 (1). We are currently
testing whether the modifier mutants of the AIY
sprouting defect are also capable of modifying
the AFD sprouting defect.
To determine the extent of cellular
responsiveness to ectopic CeKAL-1, we
expressed CeKAL-1 pan-neurally using the
promoter of unc-119, a novel pan-neural gene.
We obtained four integrated lines and
investigated these for neuronal and
non-neuronal defects. The most striking
non-neuronal defect exhibited is the vab
(variably abnormal) phenotype, suggesting
defective ventral enclosure of the hypodermis
during embryogenesis. Consistent with this, we
see embryonic expression of CeKAL-1 at the
time of ventral enclosure in cells that appear to
be neuroblasts. To investigate for neuronal
defects in the lines in which CeKAL-1 is
pan-neurally expressed, we systematically
constructed doubles with a variety of