Local Permutations in the Glomerular Array of the Mouse Olfactory Bulb
Local Permutations in the Glomerular Array of the Mouse Olfactory Bulb
复制标题
小鼠嗅球肾小球阵列中的局部排列
作者：
J. Strotmann;S. Conzelmann;A. Beck;P. Feinstein;H. Breer;P. Mombaerts
表达特定气味受体基因的嗅觉神经元将其轴突非常精确地投射到嗅球中的一些特定肾小球。目前尚不清楚这些肾小球的位置在多大程度上是固定的。我们试图通过确定肾小球的相对位置，各种气味受体，使用的方法，提供单轴突的分辨率，并在大量的灯泡在小鼠肾小球阵列的恒定性进行评估。我们使用遗传策略来可视化表达mOR 37亚家族三个成员之一的神经元群体。我们通过基因靶向产生了五种小鼠品系，其中givenmOR 37基因的表达与轴突标记物的表达相关，所述轴突标记物是taulacZ或tauGFP。标记物表达的模式忠实地模仿同源受体的模式。表达给定mOR 37基因的神经元的轴突会聚到每个球的一个或两个肾小球上。每个mOR 37基因具有其自己的肾小球，并且mOR 37肾小球被分组在球的限制性结构域内。214个球的连续切片显示，三种类型的肾小球的相对位置不是固定的，而是显示局部排列。重要的是，这也是来自一个个体的两个灯泡的情况，排除了遗传操作本身以及遗传背景或嗅觉经验的差异作为观察到的变异性的原因。这些局部排列可能反映了肾小球的发育历史，并与空间气味图的构建有关。
Olfactory sensory neurons expressing a given odorant receptor gene project their axons with great precision to a few specific glomeruli in the olfactory bulb. It is not clear to which extent the positions of these glomeruli are fixed. We sought to evaluate the constancy of the glomerular array in the mouse by determining the relative positions of glomeruli for various odorant receptors, using a method that affords single-axon resolution, and in a large number of bulbs. We used a genetic strategy to visualize neuronal populations that express one of three members of the mOR37 subfamily. We generated by gene targeting five strains of mice in which expression of a givenmOR37 gene is linked to expression of an axonal maker, which is either taulacZ or tauGFP. The patterns of marker expression faithfully mimic those of the cognate receptors. Axons of neurons expressing a given mOR37 gene converge onto one or two glomeruli per bulb. Each mOR37 gene has its own glomeruli, and the mOR37 glomeruli are grouped within a restricted domain of the bulb. Serial sectioning of 214 bulbs reveals that the relative positions of the three types of glomeruli are not fixed but display local permutations. Importantly, this is also the case among the two bulbs from one individual, ruling out the genetic manipulation itself and differences in genetic background or olfactory experience as causes for the observed variability. These local permutations may reflect the developmental history of the glomeruli and are relevant for the construction of spatial odor maps.