Comery T A, Harris J B, Willems P J, Oostra B A, Irwin S A, Weiler I J, Greenough W T
Neuroscience Program, University of Illinois, Urbana-Champaign, IL 61801, USA.
Proc Natl Acad Sci U S A. 1997 May 13;94(10):5401-4. doi: 10.1073/pnas.94.10.5401.
Fragile X syndrome arises from blocked expression of the fragile X mental retardation protein (FMRP). Golgi-impregnated mature cerebral cortex from fragile X patients exhibits long, thin, tortuous postsynaptic spines resembling spines observed during normal early neocortical development. Here we describe dendritic spines in Golgi-impregnated cerebral cortex of transgenic fragile X gene (Fmr1) knockout mice that lack expression of the protein. Dendritic spines on apical dendrites of layer V pyramidal cells in occipital cortex of fragile X knockout mice were longer than those in wild-type mice and were often thin and tortuous, paralleling the human syndrome and suggesting that FMRP expression is required for normal spine morphological development. Moreover, spine density along the apical dendrite was greater in the knockout mice, which may reflect impaired developmental organizational processes of synapse stabilization and elimination or pruning.
脆性X综合征源于脆性X智力低下蛋白（FMRP）的表达受阻。对脆性X患者经高尔基染色的成熟大脑皮层进行观察，发现其突触后棘突长、细且扭曲，类似于正常早期新皮层发育过程中观察到的棘突。在此，我们描述了转基因脆性X基因（Fmr1）敲除小鼠经高尔基染色的大脑皮层中的树突棘，这些小鼠缺乏该蛋白的表达。脆性X敲除小鼠枕叶皮层V层锥体细胞顶端树突上的树突棘比野生型小鼠的更长，且通常细而扭曲，这与人类综合征相似，表明FMRP表达是正常棘突形态发育所必需的。此外，敲除小鼠顶端树突上的棘突密度更大，这可能反映了突触稳定、消除或修剪的发育组织过程受损。
