Embryonic stem cell self-renewal

胚胎干细胞是一种来源于植入前内细胞团的多能干细胞。 胚泡。胚胎干细胞为阐明基因功能和建立疾病模型提供了一个强大的平台。到目前为止, 基于胚胎干细胞的技术的应用一直局限于小鼠和大鼠，因为生殖系具有 胚胎干细胞尚未从非啮齿动物物种中建立起来。我们之前的工作确立了高效的自我 双重抑制糖原合成酶激酶3(GSK3)可实现小鼠和大鼠胚胎干细胞的更新 和丝裂原活化蛋白激酶(MEK)。Gsk3有两个类似的成员，Gsk3α和Gsk3β， 它们共享几乎相同的激活域。同样，细胞外信号调节激酶(ERK)，唯一的 已知的MEK的生理底物也有两个高度同源的类似物，ERK1和ERK2。尽管 它们的高度同源性，Gsk3α和Gsk3β在调节胚胎干细胞自我更新方面具有不同的功能； ERK1和ERK2的情况也是如此。因此，GSK3和ERK信号的微调变得至关重要 在实现最优的ESC自我更新方面。通过利用化学成因方法和ESC 平台上，我们建议研究个体不同功能的分子机制 在ESC自我更新中，GSK3和ERK类似。在目标1中，我们将识别和表征GSK3 Paralog- 具体的底物和下游目标。我们还将确定与 Gsk3α和Gsk3β的不同功能。在目标2中，我们将确定和描述ERK Paralog特异性 研究ERK1和ERK2的亚细胞定位 影响它们在胚胎干细胞中的功能。在目标3中，我们将微调小鼠和人类幼稚的GSK3和ERK信号 以达到最佳的自我更新效果。在这三个目标上取得成功不仅将为 ESC自我更新的分子基础，也将对我们的深刻影响 了解GSK3和ERK功能失调引起的病理状态。

Embryonic stem cells (ESCs) are pluripotent stem cells derived from the inner cell mass of the pre-implantation blastocyst. ESCs provide a powerful platform for elucidating gene function and creating disease models. So far, the application of ESC-based technologies has been limited to mice and rats, because germline competent ESCs have not yet been established from non-rodent species. Our previous work established that efficient self- renewal of mouse and rat ESCs could be achieved by dual inhibition of glycogen synthase kinase 3 (GSK3) and mitogen-activated protein kinase kinase (MEK). GSK3 has two paralogous members, GSK3α and GSKβ, which share nearly identical kinase domains. Similarly, extracellular signal-regulated kinase (ERK), the only known physiological substrates of MEK, also has two highly homologous paralogs, ERK1 and ERK2. Despite their high levels of homology, GSK3α and GSK3β possess distinct functions in regulating ESC self-renewal; the same is the case for ERK1 and ERK2. Therefore, fine-tuning of GSK3 and ERK signaling becomes critical in achieving optimal ESC self-renewal. By taking advantage of the chemical-genetic approach and the ESC platform, we propose to investigate the molecular mechanisms underlying the distinct functions of individual GSK3 and ERK paralogs in ESC self-renewal. In Aim 1, we will identify and characterize GSK3 paralog- specific substrates and downstream targets. We will also determine the amino acid variances responsible for the distinct functions of GSK3α and GSK3β. In Aim 2, we will identify and characterize ERK paralog-specific substrates in the cytoplasm and nucleus and investigate how subcellular localization of ERK1 and ERK2 affects their functions in ESCs. In Aim 3, we will fine-tune GSK3 and ERK signaling in mouse and human naïve ESCs to achieve optimal self-renewal effect. Success with these three aims will not only provide insights into the molecular basis of ESC self-renewal, but will also have far-reaching implications for our deep understanding of pathological conditions caused by dysfunction of GSK3 and ERK.