Olfactory sensory neurons (OSNs) are bipolar neurons, unusual because they turn over continuously and have a multiciliated dendrite. The extensive changes in gene expression accompanying OSN differentiation in mice are largely known, especially the transcriptional regulators responsible for altering gene expression, revealing much about how differentiation proceeds. Basal progenitor cells of the olfactory epithelium transition into nascent OSNs marked by Cxcr4 expression and the initial extension of basal and apical neurites. Nascent OSNs become immature OSNs within 24-48 h. Immature OSN differentiation requires about a week and at least 2 stages. Early-stage immature OSNs initiate expression of genes encoding key transcriptional regulators and structural proteins necessary for further neuritogenesis. Late-stage immature OSNs begin expressing genes encoding proteins important for energy production and neuronal homeostasis that carry over into mature OSNs. The transition to maturity depends on massive expression of one allele of one odorant receptor gene, and this results in expression of the last 8% of genes expressed by mature OSNs. Many of these genes encode proteins necessary for mature function of axons and synapses or for completing the elaboration of non-motile cilia, which began extending from the newly formed dendritic knobs of immature OSNs. The cilia from adjoining OSNs form a meshwork in the olfactory mucus and are the site of olfactory transduction. Immature OSNs also have a primary cilium, but its role is unknown, unlike the critical role in proliferation and differentiation played by the primary cilium of the olfactory epithelium's horizontal basal cell.

中文翻译：

---

嗅觉神经元及其纤毛的成熟。

嗅觉感觉神经元 (OSN) 是双极神经元，不同寻常，因为它们不断翻转并具有多纤毛树突。小鼠中伴随 OSN 分化的基因表达的广泛变化广为人知，尤其是负责改变基因表达的转录调节因子，揭示了很多关于分化如何进行的信息。嗅觉上皮的基底祖细胞转变为以 Cxcr4 表达和基底和顶端神经突的初始延伸为标志的新生 OSN。新生的 OSN 在 24-48 小时内变成不成熟的 OSN。不成熟的 OSN 分化需要大约一周的时间和至少 2 个阶段。早期未成熟的 OSN 启动编码关键转录调节因子和进一步神经发生所需的结构蛋白的基​​因表达。晚期未成熟的 OSN 开始表达编码蛋白质的基因，这些蛋白质对能量产生和神经元稳态很重要，这些蛋白质会延续到成熟的 OSN 中。向成熟的过渡取决于一种气味受体基因的一个等位基因的大量表达，这导致成熟 OSN 表达的最后 8% 的基因表达。这些基因中的许多基因编码的蛋白质对于轴突和突触的成熟功能或完成非活动纤毛的精细化是必需的，非活动纤毛开始从未成熟 OSN 的新形成的树突状结延伸。来自相邻 OSN 的纤毛在嗅觉粘液中形成网状结构，并且是嗅觉转导的部位。未成熟的 OSN 也有初级纤毛，但其作用未知，