Miller J D, Hadley R D, Hammond C E
Department of Cell Biology and Anatomy, Medical University of South Carolina, Charleston 29425.
Brain Res Dev Brain Res. 1994 Jun 17;79(2):203-18. doi: 10.1016/0165-3806(94)90125-2.
Helisoma neurons require a factor(s) present in conditioned medium (CM), for successful neurite outgrowth in vitro. A approximately 300 kDa Helisoma extracellular matrix (ECM) protein has been identified in CM and is necessary for neurite initiation. Here we show that purified approximately 300 kDa ECM protein supports outgrowth. Furthermore, anti- approximately 300 kDa Fab fragments cause a rapid, dose-dependent decrease in outgrowth when added to neurons already growing in CM, culminating in growth cone collapse and neurite retraction at 200 micrograms/ml. Collapsing growth cones rapidly lost lamellipodia and filopodia transformed into long filamentous strands. Contortion of microtubules in retracting neurites into serpentine shapes, apparently by compressive forces, suggests that large-scale microtubule depolymerization is not a prerequisite for growth cone retraction. These results imply that substrate-bound approximately 300 kDa CM protein is necessary and sufficient for CM-stimulated growth cone initiation and neurite elongation from Helisoma neurons.
在体外培养中，椎实螺神经元轴突的成功生长需要条件培养基（CM）中存在某种因子。已在CM中鉴定出一种约300 kDa的椎实螺细胞外基质（ECM）蛋白，它是轴突起始所必需的。在此我们表明，纯化的约300 kDa ECM蛋白能支持轴突生长。此外，当将抗约300 kDa Fab片段添加到已在CM中生长的神经元中时，会导致轴突生长迅速、剂量依赖性地减少，在200微克/毫升时最终导致生长锥塌陷和轴突回缩。塌陷的生长锥迅速失去片状伪足，丝状伪足转变为长丝状束。在回缩轴突中微管扭曲成蛇形，显然是由压缩力所致，这表明大规模微管解聚不是生长锥回缩的先决条件。这些结果意味着，与底物结合的约300 kDa CM蛋白对于CM刺激的椎实螺神经元生长锥起始和轴突伸长是必要且充分的。
