Identification and characterization of FGF target genes

FGF 靶基因的鉴定和表征

• 批准号: 10702527
• 负责人: MARK B LEWANDOSKI
• 金额: $ 31.49万
• 依托单位: DIVISION OF BASIC SCIENCES - NCI
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10702527
• 关键词: Address; Anatomy; Apoptotic; Behavior; Cardiac; Cell Death; Cell Proliferation; Cells; Chronic Kidney Failure; Cis-Acting Sequence; Connective Tissue; Data; Defect; Dermis; Development; Differentiated Gene; Disease; Dorsal; Embryo; Embryonic Development; Family member; Fibroblast Growth Factor; Future; GBX1 gene; Gene Expression; Gene Expression Profiling; Gene Family; Gene Targeting; Genes; Genetic; Goals; Growth Factor Gene; Human; Interneurons; Knowledge; Label; Malignant Neoplasms; Mantle Zone; Mesoderm; Messenger RNA; Modeling; Molecular; Motor Neurons; Muscle; Mutant Strains Mice; Pathology; Pathway interactions; Periodicity; Play; Reaction; Regulation; Regulatory Element; Role; Segmentation Clock Pathway; Signal Pathway; Signal Transduction; Somites; Spinal Cord; Trans-Activators; Transcription Repressor; Vertebral column; Work; angiogenesis; base; bone; cell behavior; combinatorial; insight; member; migration; mutant; neurogenesis; notch protein; novel; prevent; somitogenesis; spine bone structure; synergism; transcription factor

To address the deficiency in our knowledge of what genes respond to FGF signaling, we have an ongoing project to molecularly define FGF targets genes, as well as their function and regulation. In past work, we and others have identified the transcription factors encoded by Gbx1 and Gbx2 as FGF targets. Recently we investigated the functional relationship between Gbx family members in the developing spinal cord using combinatorial Gbx mouse mutants. We showed that each Gbx gene is upregulated if the other is absent. Additionally, Gbx genes regulate development of a subset of PAX2+ dorsal inhibitory interneurons. Also, expansion of proliferative cells into the anatomically defined mantle zone occurs in Gbx mutants. Lastly, our data shows a marked increase in apoptotic cell death in the ventral spinal cord of Gbx mutants during mid-embryonic stages. While our studies reveal that both members of the Gbx gene family are involved in development of subsets of PAX2+ dorsal interneurons and survival of ventral motor neurons, Gbx1 and Gbx2 are not sufficient to genetically compensate for the loss of one another. Thus, our studies provide novel insight to the relationship harbored between Gbx1 and Gbx2 in spinal cord development (J Dev Biol. 2020. PMID: 32244588). In current work, we demonstrate that the Hes7 transcriptional repressor may be a direct target of Fgf4 signaling. During vertebrate development, the presomitic mesoderm (PSM) is periodically segmented into somites, which will form the segmented vertebral column and associated muscle, connective tissue, and dermis. The periodicity of somitogenesis is regulated by a segmentation clock of oscillating Notch activity. We examined mouse mutants lacking only Fgf4 or Fgf8, which we previously demonstrated act redundantly to prevent PSM differentiation. Fgf8 is not required for somitogenesis, but Fgf4 mutants display a range of vertebral defects. Analyzing gene expression with spatial model-based quantification of mRNAs fluorescently labeled by hybridization chain reaction, we show that FGF4 controls Notch pathway oscillations through the transcriptional repressor, HES7. We support this hypothesis by demonstrating a genetic synergy between Hes7 and Fgf4, but not with Fgf8. Thus, we establish Fgf4 as an essential Notch oscillation regulator and potentially important in a spectrum of human Segmentation Defects of the Vertebrae caused by defective Notch oscillations. (eLife 2020 Nov 19;9:e55608. doi: 10.7554/eLife.55608.) Future work will focus on what regulatory elements within the Hes7 gene are responsive to Fgf4 signals.

为了解决我们对什么基因对成纤维细胞生长因子信号做出反应的认识不足，我们有一个正在进行的项目，从分子上定义成纤维细胞生长因子靶标基因，以及它们的功能和调节。在过去的工作中，我们和其他人已经将Gbx1和Gbx2编码的转录因子确定为成纤维细胞生长因子的靶标。最近，我们利用GBX小鼠的组合突变体研究了GBX家族成员在脊髓发育过程中的功能关系。我们证明，如果另一个基因缺失，两个GBX基因都上调。此外，GBX基因还调控PAX2+背侧抑制性中间神经元的发育。此外，在GBX突变体中，增殖细胞扩张到解剖学上定义的外套层区域。最后，我们的数据显示，在胚胎中期，GBX突变体腹侧脊髓中的凋亡细胞死亡显著增加。虽然我们的研究表明，GBX基因家族的两个成员都参与了PAX2+背侧中间神经元亚群的发育和腹侧运动神经元的存活，但Gbx1和Gbx2不足以在遗传上补偿彼此的损失。因此，我们的研究为Gbx1和Gbx2在脊髓发育中的关系提供了新的见解(J Dev Biol。2020年。PMID：32244588)。在目前的工作中，我们证明了Hes7转录抑制因子可能是Fgf4信号的直接靶点。在脊椎动物的发育过程中，节前中胚层(PSM)周期性地被分割成体节，形成节段的脊椎及其相关的肌肉、结缔组织和真皮。体细胞发生的周期性受Notch振荡活动的分段时钟的调节。我们检查了只缺少Fgf4或Fgf8的小鼠突变体，我们之前证明了它们是冗余的，可以防止PSM分化。Fgf8不是体细胞发生所必需的，但Fgf4突变会显示出一系列的脊椎缺陷。通过杂交链式反应荧光标记的mRNAs的空间模型定量分析基因表达，我们发现FGF4通过转录抑制因子HES7控制Notch途径的振荡。我们通过证明Hes7和Fgf4之间的遗传协同作用来支持这一假设，但不是与Fgf8之间的遗传协同作用。因此，我们确定Fgf4是一种重要的Notch振荡调节因子，并且在由Notch振荡缺陷引起的人类椎骨节段性缺陷的谱系中具有潜在的重要作用。(eLife 2020 11月19日；9：e55608。DOI：10.7554/eLife.55608.)未来的工作将集中在Hes7基因中哪些调控元件对Fgf4信号做出反应。