Identification of possible hypoxia sensor for behavioral responses in a marine annelid, Capitella teleta

摘要

Hypoxia often occurs in summer and causes deleterious effects on marine benthic animals. A marine annelid,Capitella teleta, is tolerant to hypoxia, as shown by the fact that it inhabits organically polluted areas, where severe hypoxia is often observed. To understand how this species adapts to the environment, we focused on its hypoxia sensor, and we showed that TRPAbasal was a possible contributor to hypoxia detection inC. teleta. To examine the involvement of TRPA1 in the response ofC. teletato hypoxia, we exposedC. teletato hypoxic water with or without a TRPA1-specific inhibitor, A-967079. Hypoxic stimulation induced escape behavior inC. teletafrom the sediment, and this behavior was suppressed by the inhibitor. The cloned TRPA gene fromC. teletawas phylogenetically categorized intoTRPAbasal, and contains an oxygen-dependent degradation domain, which is important for the detection of hypoxia. Whole-mountin situhybridization analysis showed that the gene was transcribed in the prostomium, where sensing functions are localized. These results suggested that the worm has a hypoxia-sensing system possibly utilizing CtTRPAbasal, and this system contributes to expanding the organism's niches in hypoxic environments by detecting whether hypoxia exceeds a level that would imperil its survival.