unc-2 encodes the alpha-1 subunit of a voltage-gated calcium channel that is required for many C. elegans behaviors including adaptation to dopamine and serotonin, control of egg-laying, and locomotion. Many
unc-2 alleles have been identified in screens; however, none are known to be a null. We are using a non-complementation screen to generate new deletion alleles in order to recover an
unc-2 null. This screen uses a strain from Ron Plasterk containing a Tc1 insertion in a large intron of
unc-2 (
unc-2(
pk95)), and a linked mutation in
dpy-3. To identify deletion alleles, we mated
unc-2(
mu74) males to this strain and screened for Unc cross progeny that indicate a failure to complement the
mu74 mutation. We have isolated one deletion allele,
lj2, that we believe is a null or a near null. It contains a deletion of most of the fourth membrane domain, the C terminus, and the 3! UTR. The phenotype is more severe than the
mu74 allele; it is much more sluggish and has lower fertility. We have also found a deletion allele,
lj1, with a less severe phenotype, that is similar to
mu74. Surprisingly, this allele has a large deletion that removes most of the third and fourth membrane domains, suggesting that alpha-1 subunits retain some biological activity even without four functional membrane domains. To investigate the cell biology of the UNC-2 calcium channel, we have generated antibodies to two UNC-2 cytoplasmic regions. Immunolocalization data will hopefully be presented.