Menco B P, Tekula F D, Farbman A I, Danho W
Department of Neurobiology and Physiology, Northwestern University, Evanston, IL 60208-3520.
J Neurocytol. 1994 Nov;23(11):708-27. doi: 10.1007/BF01181645.
Light microscopic immunohistochemistry coupled with freeze-substitution electron microscopic immunocytochemistry was used to localize alpha-subunits of G-proteins and type III adenylyl cyclase in developing rat olfactory epithelia. Some cilia immunoreacted with antibodies to GS alpha and type III adenylyl cyclase as early as prenatal day 15 (E15; E1 = sperm-positive), but immunolabelling with antibodies to Golf alpha was not observed until E16. From then on numbers of receptor cells with immunolabelled cilia increased for all three probes. Immunoreactivity for antibodies to the olfactory signal-transduction proteins tended to parallel cilium development, though Golf alpha lags somewhat behind. Newly formed cilia labelled along their lengths, whereas mature cilia labelled predominantly along their long distal parts. Dendritic knobs and ciliary necklaces showed little or no labelling. While at E22 most multiciliate cells immunolabelled with antibodies to Gs alpha, Golf alpha, and type III adenylyl cyclase, not all of these cells labelled with antibodies to olfactory marker protein. Olfactory axons immunoreacted more intensely than epithelial surface structures with antibodies to Gs alpha at E15; the reverse occurred by about E18. Immunoreactivity with antibodies to alpha-subunits of the G-proteins Go, Gq/G11, and Gi was also found as early as E15. Antibodies to Go alpha labelled receptor cell dendritic knobs and cilia during development only. Antibodies to Gi alpha labelled Bowman's glands, whereas those to Gq alpha/G11 alpha bound to receptor cell cilia and axons (primarily vomeronasal), and supporting cell microvilli. We propose that Gs is the predominant G protein in cilia of immature olfactory receptor cells, while Golf is predominant in cilia of mature cells. Axonal immunoreactivity for some G-protein antibodies suggests G-protein participation in processing of olfactory axon and/or axon terminal-bound signals.
运用光学显微镜免疫组织化学技术并结合冷冻置换电子显微镜免疫细胞化学技术，对发育中的大鼠嗅觉上皮中的G蛋白α亚基和Ⅲ型腺苷酸环化酶进行定位。早在胚胎第15天（E15；E1 = 精子阳性日），一些纤毛就与针对Gsα和Ⅲ型腺苷酸环化酶的抗体发生免疫反应，但直到E16才观察到与Golfα抗体的免疫标记。从那时起，所有三种探针的免疫标记纤毛的受体细胞数量都增加了。针对嗅觉信号转导蛋白抗体的免疫反应性往往与纤毛发育平行，尽管Golfα稍显滞后。新形成的纤毛沿其长度被标记，而成熟纤毛主要沿其长的远端部分被标记。树突状小体和纤毛项链几乎没有或没有标记。虽然在E22时，大多数多纤毛细胞用针对Gsα、Golfα和Ⅲ型腺苷酸环化酶的抗体进行免疫标记，但并非所有这些细胞都用针对嗅觉标记蛋白的抗体进行标记。在E15时，嗅觉轴突与针对Gsα的抗体的免疫反应比上皮表面结构更强烈；大约在E18时情况相反。早在E15时也发现了与G蛋白Go、Gq/G11和Gi的α亚基抗体的免疫反应性。针对Goα的抗体仅在发育过程中标记受体细胞的树突状小体和纤毛。针对Giα的抗体标记鲍曼腺，而针对Gqα/G11α的抗体与受体细胞的纤毛和轴突（主要是犁鼻器）以及支持细胞的微绒毛结合。我们认为，Gs是未成熟嗅觉受体细胞纤毛中的主要G蛋白，而Golf是成熟细胞纤毛中的主要G蛋白。一些G蛋白抗体的轴突免疫反应性表明G蛋白参与嗅觉轴突和/或轴突末端结合信号的处理。
