Olfactory bulb axonal outgrowth is inhibited by draxin
Olfactory bulb axonal outgrowth is inhibited by draxin
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DOI：
10.1016/j.bbrc.2010.07.010
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发表时间：
2010-08-06
影响因子：
3.1
通讯作者：
Tanaka, Hideaki
中科院分区：
文献类型：
--
作者：
Ahmed, Giasuddin;Shinmyo, Yohei;Tanaka, Hideaki
嗅球投射神经元接收来自嗅觉受体神经元的感觉输入，并通过其轴突将其精确地传递到嗅觉皮层。因此，嗅球轴突束在将信息传递到大脑中更高级的嗅觉结构中起着重要作用。几类轴突导向分子影响嗅球轴突的寻路。Draxin是一种最近发现的新型排斥性轴突导向蛋白，对于前脑连合的形成至关重要，并且可以介导鸡和小鼠不同类别神经元的排斥。在这项研究中，我们研究了Draxin在小鼠端脑的表达模式及其对OB轴突向端脑投射的指导作用。我们发现，Draxin在E13和E17.5的新皮层和隔中表达，此时OB投射神经元沿端脑腹外侧沿着吻尾方向形成外侧嗅束（LOT）。Draxin在体外抑制来自嗅球外植体的轴突生长，并检测体内LOT轴突中的Draxin结合活性。LOT在屈氧西林-/-小鼠中正常发育，尽管在这些突变体的肠道中存在轻微的去纤维化。这些结果表明，draxin功能作为OB轴突的抑制性指导线索，并表明其对LOT的形成的贡献。(c)2010年爱思唯尔公司All rights reserved.
Olfactory bulb (OB) projection neurons receive sensory input from olfactory receptor neurons and precisely relay it through their axons to the olfactory cortex. Thus, olfactory bulb axonal tracts play an important role in relaying information to the higher order of olfactory structures in the brain. Several classes of axon guidance molecules influence the pathfinding of the olfactory bulb axons. Draxin, a recently identified novel class of repulsive axon guidance protein, is essential for the formation of fore-brain commissures and can mediate repulsion of diverse classes of neurons from chickens and mice. In this study, we have investigated the draxin expression pattern in the mouse telencephalon and its guidance functions for OB axonal projection to the telencephalon. We have found that draxin is expressed in the neocortex and septum at E13 and E17.5 when OB projection neurons form the lateral olfactory tract (LOT) rostrocaudally along the ventrolateral side of the telencephalon. Draxin inhibits axonal outgrowth from olfactory bulb explants in vitro and draxin-binding activity in the LOT axons in vivo is detected. The LOT develops normally in droxin-/- mice despite subtle defasciculation in the tract of these mutants. These results suggest that draxin functions as an inhibitory guidance cue for OB axons and indicate its contribution to the formation of the LOT. (c) 2010 Elsevier Inc. All rights reserved.