Genome maintenance functions of CREB/ATF transcription factors

CREB/ATF转录因子的基因组维持功能

• 批准号: 8737817
• 负责人: Randal Scot Tibbetts
• 金额: $ 26.94万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-09-19 至 2017-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8737817
• 关键词: ATM gene; ATM wt Allele; Acetylation; Alleles; Animal Model; Ataxia Telangiectasia; Ataxia-Telangiectasia-Mutated protein kinase; Binding Proteins; Biological Assay; Brain; CREB-binding protein; Calcium; Cell model; Chromatin; Chronic; Complex; Cyclic AMP; Cyclic AMP-Responsive DNA-Binding Protein; DNA; DNA Damage; DNA Double Strand Break; DNA Repair; DNA-dependent protein kinase; Defect; Development; Double Strand Break Repair; Down-Regulation; EP300 gene; Environment; Exhibits; Family; Gene Expression; Gene Expression Profile; Gene Targeting; Genetic; Genetic Transcription; Genome; Genomic Instability; Genomics; Genotoxic Stress; Glucagon; Gluconeogenesis; Goals; Growth Factor; Histone Acetylation; Histones; Housekeeping; Housekeeping Gene; Human; In Vitro; Lasers; Leucine Zippers; Long-Term Potentiation; Maintenance; Malignant Neoplasms; Measures; Mediating; Memory; Metabolic; Metabolism; Modeling; Molecular; Mus; Mutagens; Mutation; Nucleosomes; Oncogenic; Pathway interactions; Phosphorylation; Physiological; Play; Poly(ADP-ribose) Polymerases; Predisposition; Protein Binding; Protein Family; Protein p53; Proteins; Radiation; Recruitment Activity; Regulation; Resistance; Response Elements; Role; Site; Stress; Sum; Synapses; Synaptic plasticity; Syndrome; Testing; Textbooks; Tissues; Transactivation; Transcriptional Regulation; Transferase; Tumor Suppression; Tumor Suppressor Proteins; Work; activating transcription factor; activating transcription factor 1; ataxia telangiectasia mutated protein; bZIP Domain; base; casein kinase I; common cellular transcription factor ATF; human CREBBP protein; in vivo; loss of function; member; novel; overexpression; programs; protein function; public health relevance; research study; response; transcription factor; tumor; tumorigenesis

DESCRIPTION (provided by applicant): The overarching goal of this study is to define novel roles for CREB/ATF transcription factors in genome protection. Members of the CREB (cAMP response element-binding protein) family, including CREB, CREM, and ATF1, mediate transcriptional response to cAMP, calcium, and growth factors. It has long been known that CREB plays an important role in the metabolic regulation-where glucagon stimulates CREB-dependent transcriptional programs that promote gluconeogenesis-and the brain, where CREB promotes synaptic long-term potentiation and memory formation. For the past several years, our group has been studying CREB in the noncanonical context of DNA damage. We discovered that CREB is regulated by the ATM (ataxia-telangiectasia-mutated) protein kinase, which is a tumor suppressor protein that functions as master regulator of the DNA damage response (DDR). ATM phosphorylates CREB on a highly conserved cluster of Ser/Thr residues, within the CREB transactivation domain termed the ATM/CK cluster. Phosphorylation of the ATM/CK cluster antagonizes CREB transcriptional functions in vitro; however, the physiologic ramifications of CREB phosphorylation in vivo have not been established. To ascertain the functional importance of ATM-CREB regulation during the DDR, we generated CREB gene targeted mice (CREBS111A/S111A) encoding a CREB protein that is resistant to phosphorylation by ATM. Tissues from CREBS111A/S111A mice show constitutively elevated CREB activity that is resistant to downregulation by DNA damage. We will now use the CREBS111A/S111A model to test our major hypothesis that ATM-mediated CREB phosphorylation is required for downregulation of CREB transcriptional programs and tumor suppression. A key aspect of these studies is to test whether the ATM-CREB pathway synergizes with a parallel ATM-p53 pathway to mediate tumor suppression in vivo. Finally, even though CREB is best known for regulating gene expression, we recently discovered that CREB is unexpectedly recruited to sites of DNA damage. One exciting idea to emerge from this finding is that CREB harbors a novel function in DNA double-strand break repair that might be regulated by ATM. Experiments outlined in this study will test this hypothesis, which has implications for genome protection and tumor suppression. In sum, our studies will define new functions for CREB family transcription factors in genome protection. The Specific Aims of the proposal are to: (i) Characterize gene expression mechanisms in CREBS111A/S111A mice; (ii) Elucidate mechanisms and functional consequences of CREB recruitment to DNA damage; and (iii) Test whether CREBS111A/S111A mice manifest genome instability.

描述（由申请人提供）：本研究的总体目标是确定CREB/ATF转录因子在基因组保护中的新作用。CREB （cAMP反应元件结合蛋白）家族的成员，包括CREB、CREM和ATF1，介导对cAMP、钙和生长因子的转录反应。人们早就知道CREB在代谢调节（胰高血糖素刺激CREB依赖的转录程序，促进糖异生）和大脑（CREB促进突触长期增强和记忆形成）中起着重要作用。在过去的几年里，我们的团队一直在研究DNA损伤的非规范背景下的CREB。我们发现CREB受ATM（共济失调-毛细血管扩张突变）蛋白激酶的调节，这是一种肿瘤抑制蛋白，作为DNA损伤反应（DDR）的主要调节因子。ATM使CREB在一个高度保守的丝氨酸/苏氨酸残基簇上磷酸化，该簇位于CREB交易域的ATM/CK簇内。ATM/CK簇磷酸化在体外可拮抗CREB转录功能；然而，体内CREB磷酸化的生理影响尚未确定。为了确定ATM-CREB调控在DDR过程中的功能重要性，我们产生了CREB基因靶向小鼠（CREBS111A/S111A），编码抗ATM磷酸化的CREB蛋白。CREBS111A/S111A小鼠的组织显示出组构性升高的CREB活性，可抵抗DNA损伤下调。我们现在将使用CREBS111A/S111A模型来验证我们的主要假设，即atm介导的CREB磷酸化是下调CREB转录程序和肿瘤抑制所必需的。这些研究的一个关键方面是测试ATM-CREB通路是否与平行的ATM-p53通路协同在体内介导肿瘤抑制。最后，尽管CREB以调节基因表达而闻名，但我们最近发现CREB出乎意料地被招募到DNA损伤部位。从这一发现中出现的一个令人兴奋的想法是，CREB在DNA双链断裂修复中具有一种可能由ATM调节的新功能。本研究中概述的实验将验证这一假设，这对基因组保护和肿瘤抑制具有重要意义。总之，我们的研究将定义CREB家族转录因子在基因组保护中的新功能。该提案的具体目的是：(i)表征CREBS111A/S111A小鼠的基因表达机制；（ii）阐明CREB募集对DNA损伤的机制和功能后果；（iii）检测CREBS111A/S111A小鼠是否存在基因组不稳定性。