Arimatsu Y, Miyamoto M, Nihonmatsu I, Hirata K, Uratani Y, Hatanaka Y, Takiguchi-Hayashi K
Laboratory of Neuromorphology, Mitsubishi Kasei Institute of Life Sciences, Tokyo, Japan.
Proc Natl Acad Sci U S A. 1992 Oct 1;89(19):8879-83. doi: 10.1073/pnas.89.19.8879.
The timing of neocortical regional specification was examined using a monoclonal antibody, designated PC3.1, that binds a 29-kDa polypeptide and recognizes a neuronal subpopulation located in the lateral but not dorsomedial neocortex in the rat. When lateral cortical tissue fragments at embryonic days 12 and 16 were maintained in an organotypic culture system, a substantial number of neurons became PC3.1-immunopositive. In marked contrast, considerably fewer, if any, PC3.1-positive neurons were observed in cultures of dorsal cortical tissue. The selective appearance of PC3.1-immunopositive neurons was also observed in dissociated cultures derived from the lateral, but not dorsal, cortical primordium at embryonic day 13 and later. In light of previous reports showing that the interactions between developing neocortical neurons and cortical afferents begin at embryonic day 14 or later, our findings imply that some regional specification occurs well before these interactions and suggest the importance of elements intrinsic to the neocortex in establishing neocortical regional specificity. Furthermore, [3H]thymidine birth-dating experiments revealed that the majority of presumptive PC3.1-immunopositive neurons underwent their final mitosis around embryonic day 15, suggesting that the regional specification events for these neurons occur before their neurogenesis.
利用一种名为PC3.1的单克隆抗体研究了新皮质区域特化的时间，该抗体可结合一种29 kDa的多肽，并识别位于大鼠外侧而非背内侧新皮质的一个神经元亚群。当将胚胎第12天和第16天的外侧皮质组织碎片置于器官型培养系统中时，大量神经元变为PC3.1免疫阳性。与之形成显著对比的是，在背侧皮质组织培养物中观察到的PC3.1阳性神经元极少，甚至没有。在胚胎第13天及以后源自外侧而非背侧皮质原基的解离培养物中也观察到了PC3.1免疫阳性神经元的选择性出现。鉴于之前的报道显示发育中的新皮质神经元与皮质传入纤维之间的相互作用在胚胎第14天或更晚开始，我们的研究结果表明，一些区域特化在这些相互作用之前就已发生，并提示新皮质内在因素在建立新皮质区域特异性方面的重要性。此外，[3H]胸腺嘧啶核苷出生时间标记实验表明，大多数推测的PC3.1免疫阳性神经元在胚胎第15天左右进行了最后一次有丝分裂，这表明这些神经元的区域特化事件发生在其神经发生之前。
