THYROID HORMONE CONTROL OF A GENE EXPRESSION NETWORK

基因表达网络的甲状腺激素控制

• 批准号: 6381490
• 负责人: JOHN DAVID FURLOW
• 金额: $ 14.73万
• 依托单位: UNIVERSITY OF CALIFORNIA AT DAVIS
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-05-15 至 2003-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6381490
• 关键词: DNA footprinting; Xenopus; apoptosis; binding sites; collagenase; cysteine endopeptidases; developmental genetics; gel mobility shift assay; gene expression; gene induction /repression; genetic enhancer element; genetic regulatory element; genetically modified animals; hormone receptor; hormone regulation /control mechanism; metamorphosis; molecular cloning; nucleic acid sequence; reporter genes; thyroid hormones; transcription factor

Amphibian metamorphosis presents an excellent opportunity to study how hormones control gene expression networks in a tissue-specific and development stage-specific manner. During the transition from the larval tadpole to the adult frog, thyroid hormone controls the growth and differentiation of new adult structures, the remodeling of existing structures for a an adult frog, thyroid hormone lysis of entire larval organs. These morphogenetic changes are caused by gene expression changes mediated by the nuclear thyroid hormone receptors. Subtractive hybridization and candidate gene approaches have identified between twenty and thirty thyroid hormone induced and repressed genes in the reabsorbing tadpole tail, an example of hormonally controlled programmed cell death examined the downstream am signaling events that culminate in tissue specific biological responses. Furthermore, current methods such native chrromatin. We propose to determine the mechanism of thyroid hormone activation of genes that are among the last to be induced in this gene expression cascade. The genes we have chosen to study encode a secreted matrix metalloproteinase, collagenase-3 , and an intra cellular cell death inducing protease, caspase-3. Collagenase- 3 is the most strongly up-regulated gene in dying muscle cells. We will use two complementary approaches to identify and characterize the Th- responsive and basal regulatory elements in these two sequenced. The ideal test of a candidate regulatory sequence is whether or not it can support appropriate transcriptional regulation in vivo. Thus, we will recently developed transenic technologies in Xenopus laevis to screen for the minimal genomic fragment genomic DNA from the collagenase-3 and caspase-3 genes will be screened for sequences that bind to early induced transcription bind to important regulatory sequences will be functionally characterized in vivo using transgenic tadpoles, employing both gain- and hormone-induced gene expression cascade from the time of thyroid hor more binding to its receptors to the induction of a concepts, and molecular markers identified during the proposed work can be applied to other important yet complex biological problems. These include thyroid hormone control of the growth and differentiation of the amphibian limbs, and certainly steroid and thyroid hormone control of gene networks in adult and developing mammals.

两栖动物的变态为研究激素如何以组织特异性和发育阶段特异性的方式控制基因表达网络提供了一个极好的机会。在蝌蚪幼虫到成年蛙的转变过程中，甲状腺激素控制着新的成年结构的生长和分化，控制着成年蛙现有结构的重塑，控制着整个幼虫器官的甲状腺激素溶解。这些形态发生变化是由核甲状腺激素受体介导的基因表达变化引起的。减法杂交和候选基因方法已经在重吸收蝌蚪尾巴中确定了20到30个甲状腺激素诱导和抑制基因，这是激素控制的程序性细胞死亡的一个例子，研究了下游信号事件，最终导致组织特异性生物反应。此外，现有的方法如天然染色质。我们建议确定甲状腺激素激活基因的机制，这些基因是在这个基因表达级联中最后被诱导的。我们选择研究的基因编码分泌基质金属蛋白酶，胶原酶-3和细胞内细胞死亡诱导蛋白酶，半胱天冬酶-3。胶原酶- 3是死亡肌肉细胞中表达上调最强烈的基因。我们将使用两种互补的方法来识别和表征这两个序列中的Th-应答和基础调控元件。对候选调控序列的理想测试是它是否能在体内支持适当的转录调控。因此，我们将在非洲爪蟾中开发转基因技术，筛选来自胶原酶-3和caspase-3基因的最小基因组片段，筛选与早期诱导转录结合的序列，结合到重要调控序列的序列将在体内使用转基因蝌蚪进行功能表征。利用增益和激素诱导的基因级联表达，从甲状腺与受体结合的时间到诱导一个概念，在提出的工作中确定的分子标记可以应用于其他重要而复杂的生物学问题。其中包括甲状腺激素对两栖动物四肢生长和分化的控制，当然还有类固醇激素和甲状腺激素对成年和发育中的哺乳动物基因网络的控制。