The star-nosed mole reveals clues to the molecular basis of mammalian touch

Little is known about the molecular mechanisms underlying mammalian touch transduction. To identify novel candidate transducers, we examined the molecular and cellular basis of touch in one of the most sensitive tactile organs in the animal kingdom, the star of the star-nosed mole. Our findings demonstrate that the trigeminal ganglia innervating the star are enriched in tactile-sensitive neurons, resulting in a higher proportion of light touch fibers and lower proportion of nociceptors compared to the dorsal root ganglia innervating the rest of the body. We exploit this difference using transcriptome analysis of the star-nosed mole sensory ganglia to identify novel candidate mammalian touch and pain transducers. The most enriched candidates are also expressed in mouse somatosesensory ganglia, suggesting they may mediate transduction in diverse species and are not unique to moles. These findings highlight the utility of examining diverse and specialized species to address fundamental questions in mammalian biology. Examination of the transcriptome of 3 trigeminal and 3 dorsal root ganglia目前学界对哺乳动物触觉传导的分子机制尚知之甚少。为筛选新型候选传导蛋白，我们以动物界触觉最灵敏的器官之一——星鼻鼹（star-nosed mole）的星状触鼻为研究对象，解析其触觉的分子与细胞基础。本研究发现，支配星状触鼻的三叉神经节（trigeminal ganglia）中富集触觉敏感神经元；相较于支配躯体其余部位的背根神经节（dorsal root ganglia），其轻触纤维占比更高，而伤害性感受器（nociceptors）占比更低。我们利用这一特征，对星鼻鼹的感觉神经节开展转录组分析，以筛选新型的哺乳动物触觉与疼痛传导候选蛋白。富集程度最高的候选蛋白同样在小鼠躯体感觉神经节中表达，提示这些蛋白可能在多种物种中介导传导过程，并非鼹鼠所特有。本研究结果凸显了通过研究多样化特化物种，解析哺乳动物生物学基础问题的重要价值。对3个三叉神经节及3个背根神经节的转录组分析