Caroni P
Friedrich Miescher Institute, Basel, Switzerland.
Bioessays. 1997 Sep;19(9):767-75. doi: 10.1002/bies.950190906.
Nerve processes elongate, branch and form synaptic contacts in a highly regulated and specific manner. Long-distance axon elongation is restricted to the main phase of axon formation during development, but can be reinduced upon lesions in the adult (regeneration). It correlates with the expression of defined genes, including proteins involved in signalling (e.g. src, NCAM, integrins), transcription factors (e.g. c-jun) and structural proteins (e.g. actin and tubulin isoforms). Activation of an exon elongation program may require bcl-2. The formation and growth of local branches (sprouting) is controlled by mechanisms in the target region. In addition, the expression of growth-associated proteins such as GAP-43 and CAP-23 in neurons lowers the threshold for nerve sprouting and potentiates its vigour. Recent studies suggest that nerve sprouting and long-distance elongation depend on the expression of different intrinsic components in neurons. One implication of these findings is that the differential expression of genes facilitating local branching may affect structural plasticity in the intact adult nervous system.
神经突起以高度有序且特定的方式伸长、分支并形成突触连接。长距离轴突伸长在发育过程中局限于轴突形成的主要阶段，但在成体受到损伤时（再生）可再次诱导发生。它与特定基因的表达相关，这些基因包括参与信号传导的蛋白质（如src、神经细胞黏附分子、整合素）、转录因子（如c-jun）和结构蛋白（如肌动蛋白和微管蛋白异构体）。外显子伸长程序的激活可能需要bcl-2。局部分支（发芽）的形成和生长受靶区域机制的控制。此外，神经元中生长相关蛋白如GAP-43和CAP-23的表达降低了神经发芽的阈值并增强其活力。最近的研究表明，神经发芽和长距离伸长取决于神经元中不同内在成分的表达。这些发现的一个含义是，促进局部分支的基因的差异表达可能会影响完整成体神经系统的结构可塑性。
