A novel and conserved protein AHO‐3 is required for thermotactic plasticity associated with feeding states in Caenorhabditis elegans

Abstract

Although a large proportion of molecules expressed in the nervous system are conserved from invertebrate to vertebrate, functional properties of such molecules are less characterized. Here, we show that highly conserved hydrolase AHO-3 acts as a novel regulator of starvation-induced thermotactic plasticity in Caenorhabditis elegans. As wild-type animals, aho-3 mutants migrated to the cultivation temperature on a linear thermal gradient after cultivation at a particular temperature with food. Whereas wild-type animals cultivated under food-deprived condition showed dispersed distribution on the gradient, aho-3 mutants exhibited tendency to migrate toward higher temperature. Such an abnormal behavior was completely rescued by the expression of human homologue of AHO-3, indicating that the molecular function of AHO-3 is highly conserved between nematode and human. The behavioral regulation by AHO-3 requires the N-terminal cysteine cluster, which ensures the proper subcellular localization of AHO-3 to sensory endings. Double-mutant analysis suggested that AHO-3 acts in the same pathway with ODR-3, a heterotrimeric G protein alpha subunit. Our results unveiled a novel neural protein in C. elegans, confirming its conserved role in behavioral regulation.

The Caenorhabditis elegans INX‐4/Innexin is required for the fine‐tuning of temperature orientation in thermotaxis behavior

“…Each cell‐specific promoter::inx‐4 cDNA plasmids was generated using following promoters, each of which drives expression exclusively in a single class of neurons: gcy‐8p for AFD, AIYp for AIY (modified ttx‐3p ), glr‐3p for RIA, and odr‐3p3 for AWC. Cell‐specific expressions driven by each promoter in targeted cells were confirmed previously (Kobayashi et al, ; Nishio et al, ; Tanizawa et al, ).…”

“…It is known that wild‐type animals disperse on the temperature gradient in association with past starved conditions (Nishio et al, ). We also determined whether the nj24 mutation affects the thermotaxis behavior induced by starvation.…”

“…TTX index was calculated by a formula shown below. Starvation conditioning was conducted prior to assays as previously described (Nishio et al, ) . …”

“…TTX index was calculated by a formula shown below. Starvation conditioning was conducted prior to assays as previously described (Nishio et al, 2012).…”

Japanese studies on neural circuits and behavior of Caenorhabditis elegans

“…A novel type of hydrolase AHO-3 is important for this learning (Nishio et al, 2012). The expression of FAM108B1, which is a human homolog of AHO-3 and strongly expressed in the human brain, restored the defects of aho-3 mutants.…”