Role Of The Cortical Hem In Patterning The Telencephalon

这些研究的长期目标是了解哺乳动物的基本功能组织是如何 大脑皮层--皮质区地图--在发育过程中出现。我们正在测试一个模型， MAP由离散的信令中心建立。其中一个中心是皮层边缘， (WNT)和骨形态发生蛋白（BMP）蛋白。我们的初步假设是 调节区域图沿着内侧/外侧（M/L）轴的展开。此外，初步调查结果 表明hem通过产生多种细胞类型，瞬时和永久， 神经元和非神经元。在目标1中，我们将使用WNT3a基因座对hem进行命运作图，以指导Cre 表情到下摆。由此产生的小鼠品系将与携带标记基因的报告小鼠杂交 在后代中，表达WNT3a的hem细胞及其后代将被永久性地 标记。血细胞衍生的细胞将用细胞分裂、细胞类型、细胞周期、细胞周期和细胞周期的标志物来明确表征。 死亡和连通性在固定的组织中观察它们的发育和显著的迁移行为 和活切片;引导它们迁移的线索将被探索。在目标2中，我们将消融皮质边缘 利用WNT3a基因座和Cre-lox重组来指导细胞毒素向hem的表达。 皮层中的边缘被完全或部分消融，或边缘细胞被镶嵌消融（"边缘 亚型"）将在胚胎和出生后年龄进行分析。基因表达模式， 神经化学、细胞结构和功能连接将用于识别M/L的变化或丢失。 在大脑皮层形成图案通过类似的技术，我们将确定血红素衍生的损失的影响， 细胞一种可能性是皮质分层缺陷，这可能表明， 沿沿着两个轴形成图案。目标3将更具体地关注WNT和BMP信号传导的贡献 从褶边。使用经典的小鼠遗传学方法，我们将评估不同的，较低水平的 BMP信号对M/L皮质模式的影响。接下来，我们将尝试挽救导致 通过替换WNT和BMP信号，利用子宫内电穿孔介导的基因转移， 总之，这些研究应该澄清大脑皮层的正常发育，并阐明 人类大脑皮层畸形的可能原因

The long-term goal of these studies is to understand how the basic functional organization of the mammalian cerebral cortex - the cortical area map - arises in development. We are testing a model in which the area map is set up by discrete signaling centers. One such center is the cortical hem, generating Wingless-lnt (WNT) and Bone Morphogenetic Protein (BMP) proteins. Our primary hypothesis is that the cortical hem regulates development of the area map along the medial/lateral (M/L) axis. In addition, preliminary findings indicate new roles for the hem via its generation of a rich variety of cell types, transient and permanent, neuronal and non-neuronal. In Aim 1, we will fate map the hem using the WNT3a locus to direct Cre expression to the hem. The resulting mouse line will be crossed with reporter mice, carrying marker genes flanked by IoxP sites, in the offspring, WNT3a-expressing hem cells and their progeny will be permanently marked. Hem-derived cells will be definitively characterized with markers of cell division, cell type, cell death and connectivity. Their development and striking migratory behavior will be followed in fixed tissue and living slices; cues that direct their migration will be explored. In Aim 2, we will ablate the cortical hem utilizing the WNT3a locus and Cre-lox recombination to direct expression of a cellular toxin to the hem. Cortices in which the hem is entirely or partially ablated, or in which hem cells are ablated mosaically ("hem hypomorphs") will be analyzed at embryonic and postnatal ages. Gene expression patterns, neurochemistry, cytoarchitecture and functional connectivity will be used to identify shifts or loss of M/L patterning in the cortex. With similar techniques, we will determine the effects of the loss of hem-derived cells. A possibility is defective cortical lamination, which could indicate that the hem directs cortical patterning along two axes. Aim 3 will focus more specifically on the contributions of WNT and BMP signaling from the hem. Using classic mouse genetic approaches, we will evaluate the effects of different, lower levels of BMP signaling on M/L cortical patterning. Next, we will attempt to rescue particular defects that result from hem loss by replacing WNT and BMP signals, utilizing in utero electroporation-mediated gene transfer. Together these studies should clarify normal development of the cerebral cortex, and shed light on the possible causes of human cortical malformations.