The afferent innervation of the cochlea is comprised of spiral ganglion neurons (SGNs), which are characterized into four subtypes (Type 1A, B, and C and Type 2). However, little is known about the factors and/or processes that determine each subtype. Here, we present a transcriptional analysis of approximately 5,500 single murine SGNs collected across four developmental time points. All four subtypes are transcriptionally identifiable prior to the onset of coordinated spontaneous activity, indicating that the initial specification process is under genetic control. Trajectory analysis indicates that SGNs initially split into two precursor types (Type 1A/2 and Type 1B/C), followed by subsequent splits to give rise to four transcriptionally distinct subtypes. Differential gene expression, pseudotime, and regulon analyses were used to identify candidate transcription factors which may regulate the subtypes specification process. These results provide insights into SGN development and comprise a transcriptional atlas of SGN maturation across the prenatal period.

中文翻译：

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螺旋神经节神经元亚型的规范在小鼠出生前就开始了

耳蜗的传入神经支配由螺旋神经节神经元 (SGN) 组成，其分为四种亚型（1A、B 和 C 型以及 2 型）。然而，对于决定每个亚型的因素和/或过程知之甚少。在这里，我们提出了对在四个发育时间点收集的大约 5,500 个单个小鼠 SGN 的转录分析。所有四种亚型在协调的自发活动开始之前都是转录可识别的，表明初始规范过程受遗传控制。轨迹分析表明，SGN 最初分裂为两种前体类型（1A/2 型和 1B/C 型），随后分裂产生四种转录不同的亚型。差异基因表达，假时间，和调节子分析用于识别可能调节亚型规范过程的候选转录因子。这些结果提供了对 SGN 发育的见解，并构成了整个产前 SGN 成熟的转录图谱。