ATF2 in DNA damage response.

ATF2 在 DNA 损伤反应中的作用。

• 批准号: 7895827
• 负责人: Ze'ev A Ronai
• 金额: $ 37.69万
• 依托单位: SANFORD BURNHAM PREBYS MEDICAL DISCOVERY INSTITUTE
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-09-19 至 2012-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7895827
• 关键词: ATF2 gene; ATM activation; Affect; Apoptosis; Attenuated; Cell Culture Techniques; Cell Cycle; Cell Cycle Regulation; Cell Death; Cell Line; Cell physiology; Complex; Consensus; Cutaneous Melanoma; DNA Damage; DNA Double Strand Break; DNA repair protein; Data; Development; Dose; Equilibrium; Event; Family; Fission Yeast; Foundations; Genetic; Genetic Models; Genetic Transcription; Growth; HTATIP gene; Histone Acetylation; Histone H2A; Homologous Gene; Human; Hypersensitivity; Ionizing radiation; JNK-activating protein kinase; JUN gene; Link; Lymphocyte; MAPK14 gene; Mammalian Cell; Mediating; Melanoma Cell; Modeling; Modification; Mus; Mutagenesis; NBS1 gene; Organism; Pathway interactions; Phase; Phosphorylation; Phosphotransferases; Physiological; Predisposition; Proteins; Recruitment Activity; Regulatory Pathway; Relative (related person); Research Personnel; Resistance; Role; Signal Pathway; Signal Transduction; Signaling Molecule; Site; Staging; Stress; Testing; Tumorigenicity; bZIP Protein; cell growth; chromatin modification; chromatin remodeling; histone acetyltransferase; histone modification; melanoma; member; mouse model; mutant; neoplastic cell; novel; repaired; response; transcription factor; tumor; tumorigenesis

DESCRIPTION (provided by applicant): The transcription factor ATF2 contributes to cell cycle and cell death decisions upon its phosphorylation by stress kinases. We recently discovered that ATM phosphorylates ATF2 on Ser490/8 following the formation of double-stranded DNA breaks (DSBs) by ionizing radiation (IR). Consequently, ATF2 is rapidly recruited to DSB-induced foci, where it co-localizes with gamma-H2AX as well as with DNA repair proteins such as Mre11, Rad50 and NBS1 (MRN). Inhibition of ATF2 expression impairs recruitment of Mre11 and NBS1 to the repair foci and attenuates the S-phase checkpoint, and results in hypersensitivity to IR. Furthermore, ATF2 is also required for the activation of ATM, and consequently of Chk1 and Chk2. Significantly, the newly identified role of ATF2 in DNA damage response does not require its transcriptional activity. These findings provide the foundation for our hypothesis that via distinct regulatory pathways (ATM vs. JNK/p38) ATF2 contributes to separate cellular functions: transcription,and DNA damage response and consequently, tumorigenesis. We will test this hypothesis by characterizing the requirements and the mechanism(s) underlying the newly identified function of ATF2 as a regulator of the DNA damage response as it pertains to normal cellular growth and tumorigenesis. Specifically we will: (1) Characterize ATF2 as a regulator of DNA damage in the context of histone modification and ATM activation. Earlier studies established ATF2 association with components of TIP60 histone acetyltransferase complex; ATF2 homologues in S. pombe are implicated in chromatin remodeling, which is now linked with the activation of ATM. We will characterize the role of ATF2 in histone acetylation and the induction of ATM in response to DSB; (2) Utilize fission yeast as a model to genetically dissect ATF2 homolog (Atf21, Pcr1) functions in DNA damage responses. Fission yeast has long provided a paradigm for cell cycle control and DNA damage responses. The stress signaling molecules, including ATF2, are conserved in this organism, and its genetic simplicity will be utilized to independently further develop our preliminary data and to act as a genetic model to test chromatin modifications in a well defined and controlled setting; (3) Determine the effect of p38/JNK on ATM phosphorylation of ATF2 (and vice versa) in relation to ATF2 activity in transcription and the DNA damage response in non-transformed and in tumor cells; (4) Assess which of ATF2 modifications and functions (transcription/damage response) is required for its regulation of the cell cycle, growth control, apoptosis, and tumorigenicity in non transformed and in melanoma cell lines; (5) Determine changes in the skin and melanoma tumor formation and in rate of mutagenesis in mice expressing transcriptional or ATM-mutant forms of ATF2. Overall, using the powerful genetics of S. Pombe, the relevant mammalian cell cultures combined with genetic mouse models our proposal will provide important new understanding of ATF2 in transcription and DNA damage response.

描述（由申请人提供）：转录因子ATF 2通过应激激酶磷酸化参与细胞周期和细胞死亡决定。我们最近发现，ATM磷酸化ATF 2的Ser 490/8的双链DNA断裂（DSB）的形成电离辐射（IR）。因此，ATF 2被迅速募集到DSB诱导的病灶，在那里它与γ-H2 AX以及DNA修复蛋白如Mre 11、Rad 50和NBS 1（MRN）共定位。抑制ATF 2的表达会损害Mre 11和NBS 1向修复灶的募集，并减弱S期检查点，导致对IR的超敏反应。此外，ATF 2也是ATM激活所必需的，因此也是Chk 1和Chk 2激活所必需的。值得注意的是，新发现的ATF 2在DNA损伤反应中的作用并不需要其转录活性。这些发现为我们的假设提供了基础，即通过不同的调控途径（ATM与JNK/p38），ATF 2有助于单独的细胞功能：转录和DNA损伤反应，从而导致肿瘤发生。我们将通过表征新鉴定的ATF 2作为DNA损伤反应的调节剂的功能的要求和机制来测试这一假设，因为它与正常细胞生长和肿瘤发生有关。具体而言，我们将：（1）表征ATF 2作为组蛋白修饰和ATM激活背景下的DNA损伤调节因子。早期的研究证实了ATF 2与TIP 60组蛋白乙酰转移酶复合物的组分相关;粟酒裂殖酵母涉及染色质重塑，这是现在与ATM的激活。我们将研究ATF 2在组蛋白乙酰化中的作用以及DSB诱导ATM反应的机制;（2）以裂殖酵母为模型，从遗传学角度研究ATF 2同系物（Atf 21，Pcr 1）在DNA损伤反应中的功能。裂变酵母长期以来一直为细胞周期控制和DNA损伤反应提供了范例。包括ATF 2在内的应激信号分子在该生物体中是保守的，并且其遗传简单性将被用于独立地进一步开发我们的初步数据，并作为遗传模型在明确定义和受控的环境中测试染色质修饰;（3）确定p38/JNK对ATF 2的ATM磷酸化的影响（反之亦然）与转录中的ATF 2活性和非转化细胞和肿瘤细胞中的DNA损伤反应有关;（4）评估ATF 2的哪些修改和功能（转录/损伤反应）是其调节细胞周期、生长控制、凋亡和在非转化的和黑素瘤细胞系中的致瘤性;（5）测定表达转录或ATM突变形式的ATF 2的小鼠中皮肤和黑素瘤肿瘤形成以及诱变速率的变化。总的来说，利用S. Pombe，相关哺乳动物细胞培养物结合遗传小鼠模型，我们的建议将提供重要的新的理解ATF 2在转录和DNA损伤反应。

项目成果

Radiation Sensitivity and Tumor Susceptibility in ATM Phospho-Mutant ATF2 Mice.

• DOI: 10.1177/1947601910370700
• 发表时间: 2010-04-01
• 期刊: Genes & cancer
• 作者: Li S;Ezhevsky S;Dewing A;Cato MH;Scortegagna M;Bhoumik A;Breitwieser W;Braddock D;Eroshkin A;Qi J;Chen M;Kim JY;Jones S;Jones N;Rickert R;Ronai ZA
• 通讯作者: Ronai ZA