Characterizing LIN-12/Notch Regulation and Activity

秀丽隐杆线虫的生命周期包含一种称为“dauer”的发育停滞状态，该状态发生在 对不利环境条件的反应。这个 dauer 阶段是细胞长时间静止的时期 这不仅与外阴前体细胞 (VPC) 的维护相关，还与外阴前体细胞 (VPC) 的重新编程相关 进入多能状态。通常在开发过程中，VPC 命运规范需要 LIN-12/Notch，这是一种良好的 保守的跨膜受体和转录激活剂，用于靶基因的转录激活 定义未来的细胞身份。然而，在 dauer 期间，这种转录激活被阻断，即使在 存在稳定且激活的 LIN-12/Notch。此外，已经经历细胞命运的VPC LIN-12/Notch 规范在 dauer 进入时去分化为多能状态。这个块是 由胰岛素/胰岛素生长因子信号转导介导，因为其效应器转录因子 DAF- 的损失 16/FoxO，导致块的部分缓解。研究 dauer VPC 如何防止 LIN-12/Notch 信号传导方面，我将研究 LIN-12/Notch 激活复合物的 DNA 结合成分 LAG-1 是如何发挥作用的 在 dauer VPC 中受到调节，我将测试表达稳定且功能性的 LAG-1 是否会缓解 dauer 块。我还将进行阻断和未阻断之间的差异基因表达分析实验 dauer VPC 寻找可能对维持静态和静态 VPC 至关重要的候选者 多能状态。

The life cycle of Caenorhabditis elegans contains a developmentally arrested state called dauer that occurs in response to adverse environmental conditions. This dauer stage is a period of prolonged cellular quiescence that is associated with not only the maintenance but also reprogramming of the Vulval Precursor Cells (VPCs) into a multipotent state. Normally in development, VPC fate specification requires LIN-12/Notch, a well- conserved transmembrane receptor and transcriptional activator, for transcriptional activation of target genes to define the future cell identity. However, during dauer, this transcriptional activation is blocked, even in the presence of a stable and activated LIN-12/Notch. Moreover, VPCs that had already undergone cell fate specification by LIN-12/Notch are de-differentiated into a multipotent state upon dauer entry. This block is mediated by Insulin/Insulin Growth Factor Signaling, as loss of its effector, the transcriptional factor DAF- 16/FoxO, results in a partial relief of the block. To study how dauer VPCs are able to prevent LIN-12/Notch signaling, I will investigate how LAG-1, the DNA-binding component of the LIN-12/Notch activation complex, is regulated in dauer VPCs, and I will test whether expressing stable and functional LAG-1 will relieve the dauer block. I will also perform a differential gene expression analysis experiment between blocked and unblocked dauer VPCs to look for candidates that may prove essential for maintaining VPCs in a quiescent and multipotent state.