Department of Anesthesiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611.
Integrated Graduate Program in the Life Sciences (IGP), Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611.
J Comp Neurol. 2011 Apr 15;519(6):1095-1114. doi: 10.1002/cne.22554.
TRPML3 is a member of the mucolipin branch of the transient receptor potential cation channel family. A dominant missense mutation in Trpml3 (also known as Mcoln3) causes deafness and vestibular impairment characterized by stereocilia disorganization, hair cell loss, and endocochlear potential reduction. Both marginal cells of the stria vascularis and hair cells express Trpml3 mRNA. Here we used in situ hybridization, quantitative RT-qPCR, and immunohistochemistry with several antisera raised against TRPML3 to determine the expression and subcellular distribution of TRPML3 in the inner ear as well as in other sensory organs. We also use Trpml3 knockout tissues to distinguish TRPML3-specific from nonspecific immunoreactivities. We find that TRPML3 localizes to vesicles of hair cells and strial marginal cells but not to stereociliary ankle links or pillar cells, which nonspecifically react with two antisera raised against TRPML3. Upon cochlear maturation, TRPML3 protein is redistributed to perinuclear vesicles of strial marginal cells and is augmented in inner hair cells vs. outer hair cells. Mouse somatosensory neurons, retinal neurons, and taste receptor cells do not appear to express physiologically relevant levels of TRPML3. Finally, we found that vomeronasal and olfactory sensory receptor cells do express TRPML3 mRNA and protein, which localizes to vesicles in their somas and dendrites as well as at apical dendritic knobs.
TRPML3 是瞬时受体电位阳离子通道家族的粘蛋白样分支的成员。Trpml3（也称为 Mcoln3）中的显性错义突变导致耳聋和前庭功能障碍，其特征是纤毛排列紊乱、毛细胞丧失和内淋巴液电位降低。血管纹的边缘细胞和毛细胞都表达 Trpml3 mRNA。在这里，我们使用原位杂交、定量 RT-qPCR 和针对 TRPML3 几种抗血清的免疫组织化学，以确定 TRPML3 在内耳以及其他感觉器官中的表达和亚细胞分布。我们还使用 Trpml3 敲除组织来区分 TRPML3 特异性和非特异性免疫反应。我们发现 TRPML3 定位于毛细胞和血管纹边缘细胞的囊泡中，但不在纤毛足链接或支柱细胞中，这两种非特异性抗血清与 TRPML3 发生反应。在耳蜗成熟过程中，TRPML3 蛋白重新分布到血管纹边缘细胞的核周囊泡中，并在内毛细胞中增加，而在外毛细胞中减少。小鼠感觉神经元、视网膜神经元和味觉受体细胞似乎没有表达生理相关水平的 TRPML3。最后，我们发现犁鼻器和嗅觉感觉受体细胞确实表达 TRPML3 mRNA 和蛋白，其定位于它们的体部和树突中的囊泡以及顶树突棘上。
