Roles of Spartan in translesion synthesis and UV-induced carcinogenesis

Spartan 在跨损伤合成和紫外线诱发的致癌作用中的作用

• 批准号: 9319644
• 负责人: GARGI GHOSAL
• 金额: $ 13.39万
• 依托单位: UNIVERSITY OF NEBRASKA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-08-01 至 2019-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9319644
• 关键词: Binding; Biological Assay; Biological Process; Butane; Bypass; CRISPR/Cas technology; Cell Proliferation; Cell Survival; Cells; Chromatin; Cutaneous Melanoma; DNA; DNA Adducts; DNA Damage; DNA Repair Pathway; DNA biosynthesis; DNA lesion; DNA replication fork; DNA-Directed DNA Polymerase; Databases; Development; Epithelium; Fiber; Genes; Genomic Instability; In Vitro; Knock-out; Knockout Mice; Lead; Left; Lesion; Malignant Neoplasms; Mediating; Melanoma Cell; Metalloproteases; Metastatic Melanoma; Modeling; Monoubiquitination; Mus; Mutagenesis; Mutation; Pathway interactions; Peptide Hydrolases; Pharmaceutical Preparations; Physiological; Play; Polymerase; Process; Proteins; Proteolysis; Pyrimidine Dimers; Resistance; Role; Site; Skin; Skin Cancer; Skin Carcinogenesis; Sun Exposure; System; The Cancer Genome Atlas; Time; UV carcinogenesis; UV induced; UV induced DNA damage; Ubiquitination; Ultraviolet Rays; Ultraviolet Therapy; base; cancer cell; cancer therapy; chemotherapeutic agent; in vivo; insight; melanocyte; melanoma; mutant; neoplastic cell; overexpression; prevent; public health relevance; reconstitution; repaired; response; targeted cancer therapy; tumorigenesis; ultraviolet damage

 DESCRIPTION (provided by applicant): This study aims at understanding the roles of Spartan in translesion synthesis (TLS) and UV-induced carcinogenesis. TLS is a post-replication repair pathway, which mediates bypass of bulky DNA lesions that stall replication forks, during DNA replication. Bypass of DNA lesions is mediated by specialized low-fidelity TLS polymerase that can replicate over distortions or bulky DNA adducts efficiently, leaving behind the lesion to be repaired at a later time point. The critical step in TLS is the switch of the replicative polymeras with TLS polymerase, which is proposed to be mediated by RAD18-dependent ubiquitination of PCNA (ub-PCNA). However, the exact mechanism is not clear. We identified Spartan as a key regulator of TLS. Depletion of Spartan renders cells sensitive to UV damage, results in a decrease in PCNA mono-ubiquitination, which is accompanied by a reduction of RAD18 chromatin association and RAD18 localization to DNA damage sites. Interestingly, Spartan binds to replicative DNA polymerase under normal conditions, but preferentially associates with TLS polymerase POLH upon UV damage. Based on our observations, we proposed that Spartan is a key regulator of TLS, required to stabilize RAD18 and ub-PCNA at the sites of DNA damage and may directly regulate the switch from replicative polymerase to TLS polymerase during TLS. However, how Spartan mediates its regulatory functions and the switch between the DNA polymerases during TLS is not known and will be the focus of this study. The specific aims for this proposal are: Aim 1) Determine the function of Spartan in TLS upon UV damage; Aim 2) Determine the roles of Spartan mediated TLS in UV-induced carcinogenesis and resistance to chemotherapeutic agents; Aim 3) Determine the in vivo physiological functions of Spartan. This proposed study will not only provide useful insights into the regulatory mechanism of TLS process, but also, will explore the potential of targeting Spartan for cancer therapy.