Early specification and autonomous development of cortical fields in the mouse hippocampus.
Early specification and autonomous development of cortical fields in the mouse hippocampus.
复制标题
DOI：
--
复制
发表时间：
1997-12
期刊：
影响因子：
4.6
通讯作者：
Shubha Tole;Caprice Christian;Elizabeth A. Grove
中科院分区：
文献类型：
--
作者：
Shubha Tole;Caprice Christian;Elizabeth A. Grove
到目前为止，对发育中的大脑皮层不同区域的具体化的研究主要集中在新皮层上。我们证明，海马，archicortical结构，提供了一个优雅的，替代系统，探索皮质区规范。个别海马区，称为CA领域，显示出显着的分子差异的成熟。我们使用这些不同的基因表达模式作为标记CA字段的身份，并表明，两个主要的海马领域，CA1和CA3，指定在海马发育的早期，在神经发生期间。两个领域的特异性标记显示一致的模式，从胚胎到成人的表达。因此，可以在小鼠胚胎的第14.5天和第15.5天之间，即在这些区域在形态上不同的一周之前，确定推定的CA 1和CA 3区域（Pca 1，Pca 3）。在发育早期，没有其他单独的皮质区域被检测到基因表达。事实上，区分CA字段的其他特征在出生后出现，表明成熟的CA字段身份至少在3周内获得。为了确定Pca 1和Pca 3是否已被指定为获得成熟CA域身份，通过将其保持在切片培养物中将胚域与进一步的潜在指定线索分离。CA场的发展在整个胚胎海马的切片中进行。更引人注目的是，仅限于Pca 1或Pca 3的切片也发展出CA 1或CA 3的适当成熟特征。因此，Pca 1和Pca 3能够自主地发展成熟CA场身份的复杂特征，也就是说，没有来自大脑其他区域或其他部分的接触或神经支配。由于Pca 1和Pca 3可以在主要传入神经进入海马体之前被识别，因此海马体最初分为单独的区域时，神经支配也可能是不必要的。最早的场标记首先出现在海马体的两极，然后向内发展，这为真正的特定信号的来源提供了线索。一般的海马发育并不遵循这种明显的模式。我们认为，指定海马场身份的信号源靠近海马极，信号首先作用于两极的细胞，然后向内移动。
Studies of the specification of distinct areas in the developing cerebral cortex have until now focused mainly on neocortex. We demonstrate that the hippocampus, an archicortical structure, offers an elegant, alternative system in which to explore cortical area specification. Individual hippocampal areas, called CA fields, display striking molecular differences in maturity. We use these distinct patterns of gene expression as markers of CA field identity, and show that the two major hippocampal fields, CA1 and CA3, are specified early in hippocampal development, during the period of neurogenesis. Two field-specific markers display consistent patterns of expression from the embryo to the adult. Presumptive CA1 and CA3 fields (Pca1, Pca3) can therefore be identified between embryonic days 14.5 and 15.5 in the mouse, a week before the fields are morphologically distinct. No other individual cortical areas have been detected by gene expression as early in development. Indeed, other features that distinguish between the CA fields appear after birth, indicating that mature CA field identity is acquired over at least 3 weeks. To determine if Pca1 and Pca3 are already specified to acquire mature CA field identities, the embryonic fields were isolated from further potential specification cues by maintaining them in slice culture. CA field development proceeds in slices of the entire embryonic hippocampus. More strikingly, slices restricted to Pca1 or Pca3 alone also develop appropriate mature features of CA1 or CA3. Pca1 and Pca3 are therefore able to develop complex characteristics of mature CA field identity autonomously, that is, without contact or innervation from other fields or other parts of the brain. Because Pca1 and Pca3 can be identified before major afferents grow into the hippocampus, innervation may also be unnecessary for the initial division of the hippocampus into separate fields. Providing a clue to the source of the true specifying signals, the earliest field markers appear first at the poles of the hippocampus, then progress inwards. General hippocampal development does not follow this pronounced pattern. We suggest that the sources of signals that specify hippocampal field identity lie close to the hippocampal poles, and that the signals operate first on cells at the poles, then move inwards.