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--大脑皮层区域图--在发育过程中出现。我们正在测试一种模型，在该模型中， MAP由离散的信令中心建立。一个这样的中心是大脑皮层下摆，产生无翼-LNT (WNT)和骨形成蛋白(BMP)蛋白。我们的主要假设是大脑皮层下摆 调整区域地图沿内侧/外侧(M/L)轴的发展。此外，初步调查结果 通过其生成丰富多样的临时和永久的细胞类型来指示HEM的新角色， 神经性和非神经性。在目标1中，我们将使用Wnt3a轨迹来定位CRE 下摆的表情。由此产生的小鼠品系将与携带标记基因的报告小鼠杂交 在子代中，在IoxP位点两侧，表达WNT3a的HEM细胞及其后代将永久 有记号的。HEM来源的细胞将用细胞分裂、细胞类型、细胞 死亡和连接。它们的发育和惊人的迁移行为将在固定的组织中进行跟踪 和活的切片；将探索指导它们迁徙的线索。在目标2中，我们将消融皮质下摆 利用Wnt3a基因座和Cre-lox重组将细胞毒素定向表达到HEM上。 皮质，其中的下摆被完全或部分消融，或其中的下摆细胞被马赛克消融。 将在胚胎和出生后年龄进行分析。基因表达模式， 将使用神经化学、细胞结构和功能连接来确定M/L的移位或丢失 大脑皮层的花纹。用类似的技术，我们将确定折边损失的影响 细胞。一种可能是皮质层有缺陷，这可能表明下摆指向皮质。 沿着两个轴线排列。目标3将更具体地关注WNT和BMP信号的作用 从下摆开始。使用经典的小鼠遗传方法，我们将评估不同的、较低水平的影响 骨形态发生蛋白信号在M/L皮质图案上的研究。接下来，我们将尝试修复由此导致的特定缺陷 通过替换WNT和BMP信号，利用宫内电穿孔介导的基因转移，从HEM丢失。 总而言之，这些研究应该澄清大脑皮层的正常发育，并阐明 人类皮质畸形的可能原因。

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.