Corriveau R A, Shatz C J, Nedivi E
Howard Hughes Medical Institute and Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, California 94720, USA.
J Neurosci. 1999 Sep 15;19(18):7999-8008. doi: 10.1523/JNEUROSCI.19-18-07999.1999.
During visual system development, neural activity regulates structural changes in connectivity including axonal branching and dendritic growth. Here we have examined a role for the candidate plasticity gene 15 (cpg15), which encodes an activity-regulated molecule that can promote dendritic growth, in this process. We report that cpg15 is expressed in the cat visual system at relatively high levels in the lateral geniculate nucleus (LGN) but at very low levels in its synaptic target, layer 4 of the visual cortex. Prenatally, when cpg15 mRNA in the LGN is most abundant, expression is insensitive to action potential blockade by tetrodotoxin. Postnatally, activity regulation of cpg15 emerges in the LGN coincident with development of ocular dominance columns in the visual cortex. cpg15 can be detected in layers 2/3 and 5/6 of visual cortex postnatally, and expression in layers 2/3 is activity-regulated during known periods of activity-dependent plasticity for these layers. Localization and regulation of cpg15 expression in the visual system are consistent with a presynaptic role for CPG15 in shaping dendritic arbors of target neurons during activity-dependent synaptic rearrangements, both in development and adulthood.
在视觉系统发育过程中，神经活动调节连接性的结构变化，包括轴突分支和树突生长。在此，我们研究了候选可塑性基因15（cpg15）在这一过程中的作用，该基因编码一种可促进树突生长的活性调节分子。我们报告称，cpg15在猫视觉系统中的外侧膝状体核（LGN）中表达水平相对较高，而在其突触靶标——视觉皮层第4层中表达水平极低。在出生前，当LGN中的cpg15 mRNA最为丰富时，其表达对河豚毒素引起的动作电位阻断不敏感。出生后，cpg15在LGN中的活性调节与视觉皮层中眼优势柱的发育同时出现。出生后在视觉皮层第2/3层和第5/6层可检测到cpg15，并且在这些层已知的活动依赖性可塑性时期，第2/3层中的表达受活动调节。视觉系统中cpg15表达的定位和调节与CPG15在发育和成年期活动依赖性突触重排过程中塑造靶神经元树突分支的突触前作用一致。
