Challenging key concepts in neural differentiation: the role of neuromesodermal progenitors in patterning the head-to-tail axis in vertebrates

在这个项目中，这个问题将在体外小鼠多能细胞和两个体内系统，小鼠和鸡胚胎中进行研究。nmp的特征是两种转录因子T（brachyury）和Sox2的共表达。同时，Sox1的表达是未来大脑形成部位的特征。由于我们有这些群体的荧光标记，这是一个易于处理的体外系统，可以在单细胞水平上遵循形成大脑和脊髓所需的细胞命运决定序列。分析单细胞转录组与分析它们的承诺将进一步表征这些细胞命运的决定。此外，通过将未来的大脑和脊髓组织分别移植到脊髓或大脑环境中，对早期操纵小鼠和胚胎进行体外培养，将测试这些细胞在大脑或脊髓命运的哪个阶段：在它们承诺神经身份之前或之后。我们的初步数据表明，每种生物的事件序列相当相似，但这些前、后细胞类型产生的细微差异可能是物种差异的基础；这将通过小鸡和小鼠转录组的比较来分析。因此，该项目挑战了发育生物学中的一个基本概念，但也可能导致多能细胞在体外分化为临床对退行性疾病和/或损伤感兴趣的细胞类型的改进。

In this project, this question will be investigated both in vitro in mouse pluripotent cells, and in two in vivo systems, mouse and chick embryos. NMPs are characterised by the coexpression of two transcription factors, T(brachyury) and Sox2. Meanwhile Sox1 expression characterises the site of future brain formation. Since we have fluorescent markers of these populations, this is a tractable in vitro system to follow the sequence of cell fate decisions needed to make brain and spinal cord at the single cell level. Analysis of single cell transcriptomes in parallel with analysis of their commitment will further characterise these cell fate decisions. Furthermore, in vitro culture of manipulated early mouse and embryos where future brain and spinal cord tissue are challenged by transplantation to spinal cord or brain environments respectively will test at what stage these cells are committed to brain or spinal cord fates: before or after their commitment to a neural identity. Our preliminary data suggests a rather similar sequence of events in each organism, but subtle differences in the generation of these anterior and posterior cell types may underpin some of the species differences; this will be analysed by comparison of chick and mouse transcriptomes.This project therefore challenges a fundamental concept in developmental biology, but also is likely to lead to improvements in the in vitro differentiation of pluripotent cells into cell types of clinical interest for degenerative disease and/or injury.