Identification and functional analysis of a novel receptor for an odorant, benzaldehyde, in Caenorhabditis elegans.

秀丽隐杆线虫可以检测到许多化学物质，这些化学物质可以是引诱剂或驱避剂。尽管已经报道了7种不同的跨膜受体作为秀丽隐杆线虫的候选化学感觉受体，但只有Odr-10被确定为吸引剂二乙酰的受体。C06H5.7编码一个7跨膜结构域受体和odr-10。然而，它还没有被预测为候选的化学感觉受体。在本研究中，我们发现C06H5.7可能编码气味苯甲醛的受体。苯甲醛在低浓度时表现出吸引效应，在高浓度时表现出排斥效应。C06H5.7的零突变导致了苯甲醛特异性的厌恶缺陷，而不是吸引缺陷。C06H5.7在ASH化学感觉神经元中表达，该神经元感知许多厌恶刺激。另一方面，C06H5.7在AWA和AWC神经元中均未检测到，而AWA和AWC神经元是挥发性引诱剂特定亚群趋化所必需的。C06H5.7 cDNA修复了C06H5.7零突变体的苯甲醛缺陷。有趣的是，在电生理分析中，C06H5.7对苯甲醛类似物如3,4 -二羟基苯甲醛、3,4 -二羟基苯甲酸和4-羟基苯基乳酸有反应，而对苯甲醛本身没有反应。综上所述，秀丽隐杆线虫通过C06H5.7对苯甲醛产生排斥反应。此外，秀丽隐杆线虫可能将这种挥发性气味作为其在粘膜中产生的水溶性类似物。

The nematode Caenorhabditis elegans.detects many chemicals, wchich can be attractants or repellents. Although divergent seven transmembrane receptors have been reported candidates chemosensory receptors in C. elegans, only Odr-10 was identified as the receptor for an attractant, diacetyl. C06H5.7 encodes a seven transmembrane domain receptor as well as odr-10. However, it has not yet been predicted to be a candidate chemosensory receptor.In the present study, we show that C06H5.7 is likely to encode a receptor for the odorant benzaldehyde. Benzaldehyde exhibits attractive effects at low concentrations and repulsive effects at high concentrations. A null mutation in C06H5.7 caused a benzaldehyde-specific aversion defect, but not an attraction defect. C06H5.7 was expressed in the ASH chemosensory neurons, which senses many aversive stimuli. On the other hand, C06H5.7 was detected in neither AWA nor AWC neurons, which are required for chemotaxis to specific subsets of volatile attractants. The C06H5.7 cDNA rescued the benzaldehyde defect of C06H5.7 null mutant. Interestingly, C06H5.7 responded to analogues of bezaldehyde such as 3, 4-dihydroxybenzaldehyde, 3, 4-dihydroxybenzoic acid and 4-hydroxyphenyl lactic acid, but not bezaldehyde itself in electrophysiological analysis. In conclusion, C. elegans responded to benzaldehyde repulsion via C06H5.7 in ASH. Furthermore, C. elegans might detect the volatile odorant as their water-soluble analogs derived in mucosa membrane.