Tsuboi Akio, Miyazaki Takaaki, Imai Takeshi, Sakano Hitoshi
Department of Biophysics and Biochemistry, Graduate School of Science, University of Tokyo, Japan.
Eur J Neurosci. 2006 Mar;23(6):1436-44. doi: 10.1111/j.1460-9568.2006.04675.x.
Vertebrate odorant receptor (OR) genes are divided phylogenetically into two distinct classes: the fish-like class I and the terrestrial-specific class II. In the present study, we systematically analysed mouse class I OR genes (42 subfamilies) to elucidate the expression profiles in the olfactory epithelium (OE) and the projection sites of their olfactory sensory neurons (OSNs) in the olfactory bulb (OB). In situ hybridization (ISH) revealed that most class I OR genes (36 subfamilies) were expressed in the dorso-medial zone (zone 1) of the OE. Furthermore, there appeared to be no significant differences in the distributions of OSNs expressing class I genes within zone 1. These results indicate that there is a clear boundary between zone 1 and non-zone 1 areas in the OE. Some class I ORs are known to possess ligand specificity for aliphatic acids, aldehydes and alcohols. Our ISH analysis has revealed that OSNs expressing the class I ORs in zone 1 tend to converge their axons on a cluster of glomeruli in an antero-dorsal domain that is assumed to be involved in responses to the aliphatic compounds on the OB.
脊椎动物的嗅觉受体(OR)基因在系统发育上分为两个不同的类别:鱼类样的I类和陆生特有的II类。在本研究中,我们系统地分析了小鼠I类OR基因(42个亚家族),以阐明其在嗅觉上皮(OE)中的表达谱以及它们的嗅觉感觉神经元(OSN)在嗅球(OB)中的投射位点。原位杂交(ISH)显示,大多数I类OR基因(36个亚家族)在OE的背内侧区域(区域1)表达。此外,在区域1内表达I类基因的OSN分布似乎没有显著差异。这些结果表明,OE中区域1和非区域1区域之间存在明显的界限。已知一些I类OR对脂肪酸、醛和醇具有配体特异性。我们的ISH分析表明,在区域1中表达I类OR的OSN倾向于将其轴突汇聚到嗅球前背域的一组肾小球上,该区域被认为参与对OB上脂肪族化合物的反应。