Genç Bariş, Ozdinler P Hande, Mendoza April E, Erzurumlu Reha S
Department of Cell Biology and Anatomy, Louisiana State University Health Sciences Center, New Orleans, USA.
PLoS Biol. 2004 Dec;2(12):e403. doi: 10.1371/journal.pbio.0020403. Epub 2004 Nov 23.
Neurotrophin-3 (NT-3) is required for proprioceptive neuron survival. Deletion of the proapoptotic gene Bax in NT-3 knockout mice rescues these neurons and allows for examination of their axon growth in the absence of NT-3 signaling. TrkC-positive peripheral and central axons from dorsal root ganglia follow proper trajectories and arrive in close proximity to their targets but fail to innervate them. Peripherally, muscle spindles are absent and TrkC-positive axons do not enter their target muscles. Centrally, proprioceptive axons branch in ectopic regions of the spinal cord, even crossing the midline. In vitro assays reveal chemoattractant effects of NT-3 on dorsal root ganglion axons. Our results show that survival factor NT-3 acts as a short-distance axon guidance molecule for muscle sensory afferents as they approach their proper targets.
神经营养因子-3（NT-3）是本体感觉神经元存活所必需的。在NT-3基因敲除小鼠中删除促凋亡基因Bax可挽救这些神经元，并允许在没有NT-3信号传导的情况下检查它们的轴突生长。来自背根神经节的TrkC阳性外周和中枢轴突沿着正确的轨迹行进，并到达其靶标的附近，但未能支配它们。在周围，肌梭缺失，TrkC阳性轴突不进入其靶肌肉。在中枢，本体感觉轴突在脊髓的异位区域分支，甚至穿过中线。体外试验揭示了NT-3对背根神经节轴突的化学吸引作用。我们的结果表明，存活因子NT-3在肌肉感觉传入神经元接近其适当靶标时作为短距离轴突导向分子发挥作用。
