Lobster olfactory genomics.

Lobsters have numerous adaptive specializations of the olfactory system that make them especially suitable model organisms for the study of olfaction. Recent work using genomics and physiological genomics to study the lobster olfactory organ extends the advantages of their use further. A subtracted cDNA library from the mature zone of the olfactory organ and 3 physiological genomics experiments have helped identify numerous functionally interesting genes. These include specific markers of 3 cell types that previously could be discriminated only in anatomical sections, plus a marker of reactive epithelial cells at sites of cellular proliferation for both the normal ongoing replacement of olfactory tissue and the regeneration of damaged olfactory tissue. The approaches were instrumental in the discovery of a new exocrine gland, the aesthetasc tegumental gland, which is linked to grooming and the prevention of fouling of the olfactory aesthetasc setae. They also suggest a previously unknown endocrine or paracrine function performed by auxiliary cells of the olfactory aesthetasc sensory units. Other discoveries include candidates for gene products involved in olfactory transduction, presynaptic modulation of olfactory neuron axons by ionotropic receptors, and neuromodulation of both the olfactory sensory neurons and the interneurons in the olfactory lobe of the brain.