Transcriptional Regulation by the Wnt Effector POP-1

Wnt 效应器 POP-1 的转录调控

• 批准号: 8196999
• 负责人: Rueyling Lin
• 金额: $ 31.6万
• 依托单位: UT SOUTHWESTERN MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-01-13 至 2014-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8196999
• 关键词: Affect; Affinity; Amino Acids; Animals; Anterior; Binding; Biochemical; C-terminal; Caenorhabditis elegans; Cancer Etiology; Cell Nucleus; Cell division; Cells; Cessation of life; Colorectal Cancer; Complex; Daughter; Defect; Development; Diagnosis; Embryo; Embryonic Development; Endoderm; Exhibits; Genes; Genetic Transcription; Goals; Laboratories; Lead; Link; MAP Kinase Activation Pathway; MAP Kinase Signaling Pathways; Malignant Neoplasms; Mesoderm; Mitogen Activated Protein Kinase 1; Mitogen-Activated Protein Kinase Kinases; Mitogen-Activated Protein Kinases; Mitotic spindle; Modeling; Molecular; Molecular Conformation; Mutation; Nuclear; Nuclear Export; Pathway interactions; Phosphorylation; Phosphorylation Site; Phosphotransferases; Process; Public Health; RNA Interference; Regulation; Role; Rotation; Scaffolding Protein; Signal Pathway; Signal Transduction; Sister; Site; Specific qualifier value; Staging; Testing; Tissue-Specific Gene Expression; Transcription Coactivator; Transcriptional Activation; Transcriptional Regulation; Translating; cancer type; embryo stage 2; public health relevance; research study

DESCRIPTION (provided by applicant): The long-term objective of my laboratory is a detailed molecular understanding of how cell fates are regulated by division sequence and cell signaling in animal development. During C. elegans embryogenesis, Wnt and MAP kinase signaling pathways specify the endoderm precursor E. We showed that Wnt increases the level of 2-catenin/SYS and MAP kinase reduces the level of TCF/POP-1, together robustly increasing the SYS-1-to-POP ratio and transcriptional activation of endoderm genes in E. In the anterior sister of E, MS, the SYS-1-to-POP-1 ratio is low and endoderm genes are repressed. We observed the asymmetric SYS-1-to-POP-1 ratio in all A-P divisions examined and showed that it is required for all A-P fate differences examined. Studies from us and others have suggested that the MAP kinase pathway also regulates POP-1 activity, in addition to its nuclear levels. The overall objective of this proposal is to understand how phosphorylation by the MAP kinase complex, LIT-1/WRM-1, affects POP-1 activity, how POP-1 sequence itself influence its phosphorylation by LIT-1/WRM-1, and how the information in division sequence is mechanistically linked to the activation of the MAP kinase pathway. The hypotheses to be tested are: (1) LIT-1/WRM-1 regulates POP-1 activity by increasing its binding to SYS-1, in addition to reducing its nuclear levels. (2) LIT-1/WRM-1 regulates POP-1 nuclear levels and transcription activity by phosphorylating two distinct sets of sites whose phosphorylation are mutually exclusive and inhibited by each other. (3) The C-terminal domain of POP-1 promotes LIT-1/WRM-1 phosphorylation by bringing POP-1 to the kinase complex and/or presenting the phosphorylation sites. (4) The upstream regulators for the MAPK pathway also regulate spindle rotation and division axes. The specific aims are: (1) To investigate the mechanism by which LIT-1/WRM-1 coordinately regulate POP-1 nuclear level and activity. We will identify sites whose phosphorylation enhances POP-1 transcription activity. We will investigate the interactive regulation between phosphorylation sites that lower nuclear levels or increase transcriptional activation. (2) To investigate the mechanism by which the C-terminal 39 amino acids of POP-1 regulate phosphorylation by LIT-1. We will perform biochemical analyses to test models for how the POP-1 C-terminal 39 amino acids might regulate POP- 1 phosphorylation by LIT-1/WRM-1. (3) To identify additional genes in the MOM-4/LIT-1/WRM-1 MAPK pathway. RNAi screens will be performed in a background highly sensitized for defects in this pathway. We will also specifically investigate genes known to regulate cell division axes for their possible role(s) in activating this pathway. Misregulation of division axes or signaling pathways can lead to developmental defects or cancer. These experiments will aid our understanding of these processes. PUBLIC HEALTH RELEVANCE: Colorectal cancer causes more than 50,000 deaths annually in the US, and greater than 90% of these cancers are caused by activating mutations in the Wnt signaling pathway. Our ability to detect, diagnose and treat these cancers (as well as other cancer types and embryological defects caused by deregulated Wnt signaling) will rely heavily upon our understanding of this pathway, its components and their normal regulation. This proposal aims to significantly broaden our understanding of the Wnt signaling pathway, and how it intersects with other signaling pathways during development.

描述（由申请人提供）：我实验室的长期目标是对细胞命运如何受动物发育中的分裂序列和细胞信号调节的详细分子理解。 During C. elegans embryogenesis, Wnt and MAP kinase signaling pathways specify the endoderm precursor E. We showed that Wnt increases the level of 2-catenin/SYS and MAP kinase reduces the level of TCF/POP-1, together robustly increasing the SYS-1-to-POP ratio and transcriptional activation of endoderm genes in E. In the anterior sister of E, MS, the SYS-1-to-POP-1 ratio is low和内胚基因被抑制。我们观察到所有检查的A-P部门中的不对称SYS-1与POP-1比率，并表明所检查的所有A-P命运差异都是必需的。我们和其他人的研究表明，除了其核水平外，MAP激酶途径还调节POP-1活性。该提案的总体目的是了解MAP激酶复合物LIT-1/WRM-1的磷酸化如何影响POP-1活性，POP-1序列本身如何影响LIT-1/WRM-1的磷酸化以及分区序列中的信息与MAP激酶途径的激活机理链接。 要测试的假设是：（1）LIT-1/WRM-1通过增加与SYS-1的结合，除了降低其核水平外，还可以调节POP-1的活性。 （2）LIT-1/WRM-1通过磷酸化的两组磷酸化是相互排斥并彼此抑制的两组不同的位点来调节POP-1核水平和转录活性。 （3）POP-1的C末端结构域通过将POP-1带入激酶复合物和/或呈现磷酸化位点来促进LIT-1/WRM-1磷酸化。 （4）MAPK途径的上游调节器还调节主轴旋转和除法轴。 具体目的是：（1）研究LIT-1/WRM-1协调调节POP-1核水平和活性的机制。我们将确定其磷酸化增强POP-1转录活性的位点。我们将研究降低核水平或增加转录激活的磷酸化位点之间的互动调节。 （2）研究POP-1的C末端39氨基酸通过LIT-1调节磷酸化的机制。我们将对POP-1 C末端39氨基酸如何通过LIT-1/WRM-1调节POP-1磷酸化的生化分析来测试模型。 （3）在MOM-4/LIT-1/WRM-1 MAPK途径中识别其他基因。 RNAi屏幕将在该途径中的缺陷高度敏感的背景下进行。我们还将专门研究已知的基因，以调节细胞分裂轴以激活该途径的可能作用。分裂轴或信号通路的正调可能导致发育缺陷或癌症。这些实验将有助于我们理解这些过程。 公共卫生相关性：大肠癌每年在美国造成50,000多人死亡，其中90％的癌症是由Wnt信号传导途径中的突变引起的。我们检测，诊断和治疗这些癌症的能力（以及其他癌症类型和由失控的Wnt信号传导引起的胚胎缺陷）将在很大程度上取决于我们对这种途径，其成分和正常调节的理解。该建议旨在显着扩大我们对Wnt信号通路的理解，以及它如何与开发过程中其他信号通路相交。