Edgar D
J Cell Sci Suppl. 1985;3:107-13. doi: 10.1242/jcs.1985.supplement_3.11.
The survival of developing neurons is epigenetically regulated by trophic factors. Only one such protein, the nerve growth factor (NGF) has been shown to act in vivo, where it supports the survival of neural-crest-derived sensory and sympathetic neurons. Recently, however, other proteins have been isolated and shown to support the survival of cultured neurons. Furthermore, in addition to the effects of soluble trophic factors, proteins of the extracellular matrix are also able to modulate neuronal survival. Analysis of the basal lamina protein, laminin, shows that when used as a culture substrate it stimulates neurite outgrowth and potentiates neuronal survival via a site associated with its heparin binding domain. On proteolytic cleavage of laminin, however, a cryptic site is unmasked that can also promote neuronal survival and neurite growth. The properties of this cryptic site indicate that it may be similar to that of the laminin-like molecule synthesized by Schwann cells, which although recognized by anti-laminin antibodies is not inhibited by them.
发育中神经元的存活受到营养因子的表观遗传调控。目前仅有一种这样的蛋白质，即神经生长因子（NGF）已被证明在体内发挥作用，它能支持神经嵴衍生的感觉神经元和交感神经元的存活。然而，最近已分离出其他蛋白质，并证明它们能支持培养神经元的存活。此外，除了可溶性营养因子的作用外，细胞外基质的蛋白质也能够调节神经元的存活。对基底膜蛋白层粘连蛋白的分析表明，当用作培养底物时，它会刺激神经突生长，并通过与其肝素结合域相关的位点增强神经元的存活。然而，层粘连蛋白经蛋白水解切割后，一个隐蔽位点会暴露出来，该位点也能促进神经元的存活和神经突生长。这个隐蔽位点的特性表明，它可能类似于雪旺细胞合成的层粘连蛋白样分子，尽管能被抗层粘连蛋白抗体识别，但不会被它们抑制。
