The C.elegans
hab-1 gene mutants are habituated more slowly and are more rapidly recovered from habituation than wild-type animals (1). We further tested another integrative behavior of
hab-1 mutants. Brockie et al., (2) developed a simple maze assay that animals at one pole navigate through the repellent CuSO4 to the attractant diacetyl. No
hab-1(
cn308) mutant was able to arrive to the target at 24 hr, though 40 % of wild-type animals reached the target within 4 hr. Wild-type and
hab-1 animals were equally repelled by CuSO4 and were equally attracted to diacetyl when measured in the absence of CuSO4. These results suggest that the
hab-1 mutants are impaired the ability to tail effectively their movement to complex stimuli. Wild-type animals accumulate in the center of NaCl under well-fed condition but avoid NaCl after conditioning with NaCl in the presence of food (3). In contrast,
hab-1 mutants accumulated to NaCl in the presence of food but did not show response to NaCl, that is they neither avoided nor attracted to NaCl in the absence of food. These results also suggest that the
hab-1 gene is essential for general learning behavior. The
hab-1 mutant is partial resistance to aldicarb, one of AChE inhibitors, suggesting that the gene functions at the presynaptic terminal. And further, the mutant shows short life-span and hypersensitivity to volatile anesthetics, halothane. These phenotypes are similar to the mutant phenotype of
gas-1 encoding the subunit of the NADH:ubiquinone-oxidoreductase. To elucidate further the function of
hab-1, we are now in progress of cloning the gene. 1. Xu, X., Sassa,T., Kunoh, K. and Hosono, R. (2002) J.Neurogenetics 16: 29-44; 2. Brockie, P.J., Mellem J.M., Hills. T., Madsen, D.M. and Maricq, A.V. (2001) Neuron 31: 617-630; 3. Saeki, S., Yamamoto, M. and Iino, Y. (2001) J.Exp. Biol. 204:1757-1764.