Regulation and Function of the TAL1/SCL Gene

TAL1/SCL 基因的调控和功能

• 批准号: 7465258
• 负责人: STEPHEN J. BRANDT
• 金额: $ 26.81万
• 依托单位: VANDERBILT UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-01-01 至 2012-03-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7465258
• 关键词: Acute T Cell Leukemia; Address; Affinity; Anemia; BHLH Protein; Binding; Binding Proteins; Boxing; Cell Differentiation process; Chemicals; Complex; DNA; DNA Binding; DNA Sequence; DNA-Binding Proteins; Dimerization; Disease; Drosophila snf protein; E protein; Elements; Embryonic Development; Erythrocytes; Erythroid; Erythroid Cells; Funding; Gene Expression; Gene Proteins; Gene Targeting; Genes; Genetic Transcription; Globin; Helix-Turn-Helix Motifs; Hematopoietic; Histone Acetylation; Homo; Homodimerization; LIM Domain; LIM Domain Protein; LMO2 gene; Laboratories; Lead; Mediating; Mus; Nucleic Acid Regulatory Sequences; Oral cavity; Production; Protein Overexpression; Proteins; Public Health; RNA Polymerase II; Range; Regulation; Role; SS DNA BP; Series; TAL1 gene; Testing; Transcriptional Regulation; Vascular remodeling; Work; Zinc Fingers; beta Globin; erythroid differentiation; gain of function mutation; human GATA1 protein; in vitro Model; inhibitor/antagonist; insight; leukemogenesis; malignant breast neoplasm; member; mouse genome; polypeptide; progenitor; programs; promoter; transcription factor

DESCRIPTION (provided by applicant): Aberrant expression of the TAL1 (or SCL) gene is one of the most frequent gain-of-function mutations in T-cell acute lymphoblastic leukemia. This helix-loop-helix (HLH) transcription factor is also important in hematopoietic specification during embryogenesis and differentiation of the erythroid and megakaryocytic lineages postnatally. TAL1 contributes to a DNA-binding complex that contains an HLH DNA-binding partner, the GATA- 1 transcription factor, a LIM-only protein, and the LIM domain-binding protein Ldb1 and recognizes an E box- GATA DNA sequence motif. Work in the current funding period identified additional members of this complex, including the SWI/SNF protein Brg1, corepressors ETO2 and MTGR-1, and Single-Stranded DNA-Binding Protein-2 and -3. While considerable information is available about TAL1 and GATA-1, much less is known about the functions of the non-DNA-binding members of this complex. This renewal application will test the hypotheses that Ldb1 contributes importantly to the transcription of TAL1- and GATA-1 target genes and that its ability to homo-oligomerize is important for long-range control of erythroid gene expression. The first specific aim is to determine the importance of Ldb1 expression for E box-GATA DNA-binding activity, gene expression, and differentiation of murine erythroid progenitors. These studies will determine the effects of reducing Ldb1 expression on the abundance of the E box-GATA DNA-binding complex and its affinity for DNA, transcription of select target genes of the TAL1- and GATA-1-containing complex, and transcription factor occupancy, RNA polymerase II recruitment, and histone acetylation at the promoters of these genes in two in vitro models of erythroid cell differentiation. The second specific aim is to determine the contribution of Ldb1 homodimer formation to E box-GATA DNA-binding activity, short-range control of gene expression, and cellular differentiation. These studies will define the minimal domain required in Ldb1 homodimerization, determine the importance of Ldb1 homodimerization for E box-GATA DNA-binding activity, develop a specific polypeptide inhibitor of Ldb1 dimerization, and test the effect of this inhibitor on E box-GATA DNA-binding activity, erythroid gene expression, and terminal differentiation. The third specific aim is to determine the importance of Ldb1 homodimerization in long-range control of gene expression. These studies will address whether Ldb1 mediates long-range interaction of the upstream regulatory regions and promoter of the mouse beta-globin (maj) gene and identify additional loci in the mouse genome occupied by Ldb1 to elucidate its role in regulation of their transcription. The results of these studies will advance basic understanding of erythroid differentiation, have relevance to other cellular programs regulated by LIM domain and HLH proteins, and provide insights into fundamental mechanisms of transcriptional regulation and leukemogenesis. Project Narrative: The studies proposed in this application are highly relevant to public health. In addition to advancing understanding of how red blood cells are made, which is applicable to the disorder of red cell production known as anemia, this work could lead to new treatment approaches for T-cell acute lymphoblastic leukemia and cancers of the breast and oral cavity.

描述（由申请人提供）：TAL1（或SCL）基因的异常表达是T细胞急性淋巴细胞白血病中最常见的功能增益突变之一。这种螺旋 - 环螺旋（HLH）转录因子在产后胚胎和巨核细胞谱系的胚胎发生和分化过程中也很重要。 TAL1有助于DNA结合复合物，其中包含HLH DNA结合伴侣，GATA-1转录因子，单fim蛋白和LIM结构域结合蛋白LDB1，并识别E Box-Gata DNA序列基序。在当前资金期间的工作确定了该复合物的其他成员，包括SWI/SNF蛋白BRG1，Corepressors eto2和MTGR-1，​​以及单链DNA结合蛋白-2和-3。虽然可以提供有关TAL1和GATA-1的大量信息，但对于该建筑群的非DNA结合成员的功能知之甚少。该更新应用将检验LDB1对TAL1-和GATA-1靶基因转录重要贡献的假设，并且其同性化的能力对于对红细胞基因表达的长期控制很重要。第一个具体目的是确定LDB1表达对E Box-GATA DNA结合活性，基因表达和鼠红斑祖细胞的分化的重要性。这些研究将确定降低LDB1表达对E Box-GATA DNA结合复合物的丰度及其对DNA的丰富性的影响，其对TAL1-和GATA-1-1的复合物的选择靶基因的转录以及含RNA Polymase II的转录因子占用，以及在这些基因中的促进剂中的组型乙酰化的培养基丙烯酸酶，并在两种基因中均在两种基因中。第二个具体目的是确定LDB1同型二聚体形成对E Box-GATA DNA结合活性，基因表达的短距离控制和细胞分化的贡献。这些研究将定义LDB1同构化所需的最小结构域，确定LDB1同构化对E Box-GATA DNA结合活性的重要性，开发出LDB1二聚化的特定多肽抑制剂，并测试该抑制剂对E BoxA DNA dnA结合活性的效果，Erythththtroid gene gene and erythriant and Nictional and Nictinal and Nictional and Nictinal and Nictinal and Nictinal and Nictinal and Nictinal and Nictinal。第三个具体目的是确定LDB1同构化在基因表达的长期控制中的重要性。这些研究将解决LDB1是否介导了上游调节区域的远距离相互作用和小鼠β-珠蛋白（maj）基因的启动子，并确定LDB1占据的小鼠基因组中的其他基因座，以阐明其在调节其转录中的作用。这些研究的结果将提高对红细胞分化的基本了解，与由LIM结构域和HLH蛋白调节的其他细胞程序相关，并提供对转录调节和白血病发生的基本机制的见解。 项目叙述：本应用程序中提出的研究与公共卫生高度相关。除了促进对红细胞制作的理解（适用于称为贫血的红细胞疾病）的理解外，这项工作还可能导致T细胞急性淋巴细胞性白血病和乳腺癌和口腔癌的新治疗方法。