HORMONAL REGULATION OF THYROGLOBULIN GENE IN THYROIDS

本研究的长期目标是阐明 激素调节基因表达的机制 甲状腺球蛋白（TG）基因，并获得进一步的了解， 人甲状腺中该基因的控制和调节问题 肿瘤的 甲状腺功能的分化是 主要由脑垂体激素促甲状腺激素调节 （TSH）。 促甲状腺激素增强甲状腺细胞的几乎所有方面 代谢包括甲状腺球蛋白（TG）的合成， 甲状腺激素的生物合成中的前体。 在一些 甲状腺肿瘤以及一种甲状腺大鼠细胞系（FRTL-5 R）， 正常的调节机制被改变， TG与TSH无关。 在本申请中，我们建议 探讨TSH对TG基因转录的调控机制 和其他激素在正常大鼠甲状腺FRTL-5细胞中的作用。 我们将 通过融合TG基因的调控区与 细菌氯霉素乙酰转移酶（CAT）基因。 将融合基因转移至FRTL-5细胞后， 将研究TG基因控制下的CAT。 的DNA 促甲状腺激素、cAMP、胰岛素和任何其他 激素将通过TG的系统性缺失来鉴定 调控序列和缺失突变体的研究 CAT基因的激素调节。 我们还将调查 核因子的存在与这些元素相互作用， DNA迁移率改变和DNA酶I足迹分析。 可能的 cAMP的调节亚基（RI和RII）的参与- 依赖性蛋白激酶与TG激素相互作用- 还将研究监管因素。 的信息 从该细胞系获得的细胞将用于研究 TG基因的激素调节机制的改变 人甲状腺肿瘤和变体FRTL-5细胞系（FRTL- 5R）。 我们将检查（1）染色质中可能的改变 结构;（2）激素调节因子;（3） 在变体FRTL-5 R细胞中以及在FRTL-5 R细胞中的TG调节元件 人类甲状腺肿瘤

The long-term objectives of this research are to elucidate the mechanisms by which hormones regulate the expression of thyroglobulin (TG) gene and to gain further understanding of the problems of control and regulation of this gene in human thyroid tumors. The differentiated functions of the thyroid gland are regulated mainly by the pituitary gland hormone, thyrotropin (TSH). TSH enhances almost every aspect of thyroid cell metabolism including the synthesis of thyroglobulin (TG), the key precursor in the biosynthesis of thyroid hormones. In some thyroid tumors as well as in one thyroid rat cell line (FRTL-5R), the normal regulatory mechanism is altered and the synthesis of TG is independent of TSH. In this application, we propose to study the regulatory mechanisms of TG gene transcription by TSH and other hormones in normal rat thyroid FRTL-5 cells. We will construct genes by fusing the regulatory regions of TG gene with the bacterial chloramphenicol acetyltransferase (CAT) gene. Following transfer of the fused gene to FRTL-5 cells, synthesis of CAT under the control of TG gene will be investigated. The DNA regulatory elements for TSH, cAMP, insulin and any other hormone will be identified by systematic deletions of the TG regulatory sequences and investigation of the deletion mutants on hormone regulation of the CAT gene. We will also investigate the presence of nuclear factors which interact with these elements by DNA mobility shift and DNase I footprinting assay. The possible involvement of the regulatory subunits (RI and RII) of cAMP- dependent protein kinase in interaction with the TG hormonal- regulatory elements will also be investigated. The information obtained from this cell line will be applied to investigation of alterations of hormonal regulatory mechanisms of TG gene in human thyroid tumors and in the variant FRTL-5 cell line (FRTL- 5R). We will examine the possible alterations in (1) chromatin structure; (2) hormone regulatory factors and; (3) sequences of the TG regulatory elements in the variant FRTL-5R cells as well as in human thyroid tumors.