Control of epidermal self-renewing populations by bHLH and MAPK regulatory system

bHLH 和 MAPK 调节系统控制表皮自我更新群体

• 批准号: 8112005
• 负责人: DOMINIQUE C BERGMANN
• 金额: $ 29.61万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-01 至 2015-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8112005
• 关键词: Arabidopsis; Behavior; Biochemical; Biological Assay; Blood; Cancerous; Cell Lineage; Cell division; Cells; Chromatin; Data; Data Set; Development; Dimerization; Disease; Ensure; Epithelium; Gene Expression; Gene Expression Profile; Gene Family; Genes; Genetic; Genetic Screening; Goals; Harvest; Health; Human; In Vitro; Injury; Lead; Location; MAP Kinase Gene; MAPK Signaling Pathway Pathway; Maintenance; Malignant Neoplasms; Mitogen-Activated Protein Kinase Kinases; Mitogen-Activated Protein Kinases; Molecular; Molecular Genetics; Molecular Profiling; Monitor; Muscle; Mutation; Natural regeneration; Organ; Pathway interactions; Phenotype; Phosphorylation; Population; Process; Proteins; Regulation; Signal Transduction; Staging; Stem cells; System; Testing; Tissues; Variant; Work; Wound Healing; adult stem cell; base; chromatin immunoprecipitation; design; functional genomics; gain of function; gene function; in vivo; induced pluripotent stem cell; member; novel; prevent; response; self renewing cell; self-renewal; stem; stem cell differentiation; tool; transcription factor; tumor

DESCRIPTION (provided by applicant): Self renewal is integral to the creation and maintenance of many tissues and organs including human epithelia, muscle and blood systems. Each of these tissues establishes populations of self-renewing (stem) cells and must ensure that these stem cells divide and create new differentiated cells at the appropriate rate and in the appropriate place; not enough cells or divisions and the tissue will deteriorate, too many divisions and tumors can form. Our long term goal is to understand the mechanism(s) by which dispersed self-renewing populations are established and how their division and differentiation is influenced by interaction with neighboring cells. A powerful set of genetic, molecular and functional genomic tools, combined with the ability to visualize and track cell divisions makes Arabidopsis stomatal development an attractive system for investigating this set of questions. In our previous work we found that a trio of bHLH transcription factors and components of a MAPK pathway modulate division vs. differentiation choices at discrete stages in stomatal development. Based on data from genetic, biochemical and functional assays, we propose that activity of the earliest-acting bHLH in this trio, SPEECHLESS (SPCH), controls the asymmetric divisions that create the self-renewing populations. We show that SPCH is a direct target of MAP kinase-dependent phosphorylation in vitro, and that phosphorylation alters the behavior of SPCH in vivo. Our specific aims in this proposal are to: (1) elucidate the molecular mechanisms by which SPCH activity is regulated (2) Create a molecular profile of stomatal lineage cells and identify and functionally characterize transcriptional targets of SPCH in these cells, and (3) Take advantage of SPCH-induced phenotypes to genetically dissect the endogenous signaling network required to repress stem-cell differentiation. Because both the bHLH class of transcriptional regulators and the MAPK pathway are universally conserved, these studies may contribute not only to an understanding of self-renewal, but will contribute to our understanding of the diversity of MAPK and bHLH signaling mechanisms and responses. PUBLIC HEALTH RELEVANCE: Adult stem cells are called upon to regenerate or repair tissues following injury or disease. However, excess division of those same stems can lead to cancer. The proposed studies will thus help to inform strategies to induce stem cells to differentiate into specific tissues while restricting the potential for cancerous overgrowth.

描述（由申请人提供）：自我更新是许多组织和器官（包括人类上皮、肌肉和血液系统）的形成和维持不可或缺的一部分。这些组织中的每一个都建立自我更新（干）细胞群，并且必须确保这些干细胞在适当的位置以适当的速度分裂并产生新的分化细胞；没有足够的细胞或分裂，组织就会恶化，分裂太多，就会形成肿瘤。我们的长期目标是了解分散的自我更新群体建立的机制，以及它们的分裂和分化如何受到与邻近细胞相互作用的影响。一套强大的遗传、分子和功能基因组工具，加上可视化和跟踪细胞分裂的能力，使拟南芥气孔发育成为研究这组问题的一个有吸引力的系统。在我们之前的工作中，我们发现三个 bHLH 转录因子和 MAPK 通路的组件在气孔发育的不同阶段调节分裂与分化的选择。基于遗传、生化和功能测定的数据，我们提出，这三者中最早起作用的 bHLH 的活性，SPEECHLESS (SPCH)，控制着创建自我更新群体的不对称分裂。我们证明 SPCH 是体外 MAP 激酶依赖性磷酸化的直接靶标，并且磷酸化改变了 SPCH 体内的行为。我们在该提案中的具体目标是：（1）阐明调节 SPCH 活性的分子机制（2）创建气孔谱系细胞的分子谱，并识别和功能表征这些细胞中 SPCH 的转录靶标，以及（3）利用 SPCH 诱导的表型从遗传角度剖析抑制干细胞分化所需的内源信号网络。由于 bHLH 类转录调节因子和 MAPK 通路都是普遍保守的，因此这些研究不仅有助于了解自我更新，而且有助于我们了解 MAPK 和 bHLH 信号传导机制和反应的多样性。公共健康相关性：成体干细胞在受伤或疾病后被用来再生或修复组织。然而，这些茎的过度分裂可能会导致癌症。因此，拟议的研究将有助于制定诱导干细胞分化为特定组织的策略，同时限制癌性过度生长的可能性。