In mammals, the sensory experience can regulate the development of various brain structures, including the cortex, hippocampus, retina, and olfactory bulb (OB). Odor experience-evoked neural activity drives the development of dendrites on excitatory projection neurons in the OB, such as mitral and tufted cells, as well as inhibitory interneurons. OB interneurons are generated continuously in the subventricular zone and differentiate into granule cells (GCs) and periglomerular cells (PGCs). However, it remains unknown what role each type of OB interneuron plays in controlling olfactory behaviors. Recent studies showed that among the various types of OB interneurons, a subtype of GCs expressing oncofetal trophoblast glycoprotein 5T4 is required for simple odor detection and discrimination behaviors. Mouse 5T4 (also known as Tpbg) is a type I membrane glycoprotein whose extracellular domain contains seven leucine-rich repeats (LRRs) sandwiched between characteristic LRR-N and LRR-C regions. Recently, it was found that the developmental expression of 5T4 increases dramatically in the retina just before eye-opening. Single-cell transcriptomics further suggests that 5T4 is involved in the development and maintenance of functional synapses in a subset of retinal interneurons, including rod bipolar cells (RBCs) and amacrine cells (ACs). Collectively, 5T4, expressed in interneurons of the OB and retina, plays a key role in sensory processing in the olfactory and visual systems.

在哺乳动物中，感官体验可以调节各种大脑结构的发育，包括皮质，海马，视网膜和嗅球（OB）。气味引起的神经活动会驱动OB中兴奋性投射神经元（如二尖瓣和簇状细胞以及抑制性中间神经元）上树突的发育。OB中间神经元在心室下区域连续产生，并分化为颗粒细胞（GC）和肾小球周围细胞（PGC）。但是，尚不清楚每种类型的OB内部神经元在控制嗅觉行为中起什么作用。最近的研究表明，在各种类型的OB内部神经元中，表达癌胚滋养层糖蛋白5T4的GC亚型是简单的气味检测和区分行为所必需的。小鼠5T4（也称为Tpbg）是一种I型膜糖蛋白，其胞外域包含七个夹在特征性LRR-N和LRR-C区之间的富含亮氨酸的重复序列（LRR）。最近，发现了5T4睁大眼睛之前，视网膜中的视网膜急剧增加。单细胞转录组学进一步表明5T4参与视网膜中间神经元子集（包括棒状双极细胞（RBC）和无长突细胞（AC））的功能性突触的发展和维持。总的来说，5T4在OB和视网膜的中间神经元中表达的，在嗅觉和视觉系统的感觉处理中起关键作用。