2013-01-012024-05-13https://scholars.lib.ntu.edu.tw/handle/123456789/643312摘要：目前慢性B型肝炎的治療，包括固定療程的干擾素治療，或是長期的核苷酸類似物。可是持在抗病毒藥物治療下持續存在的共價閉合環狀去氧核醣核酸(cccDNA) ，是B型肝炎病毒重要的複製模板，也是目前B型肝炎病毒無法藉由抗病毒藥物根除的主要障礙。核苷酸類似物能有效地抑制B型肝炎病毒的反轉錄酶，進而抑制病毒的複製。若是一旦停藥，病毒很快就會在血液中再度出現，所以長存的共價閉合環狀去氧核醣核酸，可被視為潛伏在肝臟內的B型肝炎病毒。了解B型肝炎病毒的共價閉合環狀去氧核醣核酸的調控機轉，對B型肝炎的治療，是非常重要的。B型肝炎病毒的研究，因為缺乏一個簡便的體外系統可追蹤共價閉合環狀去氧核醣核酸的產生，所以進展不快。雖然B型肝炎病毒在人類的肝臟腫瘤細胞株中，能夠輕易產生具感染力的病毒顆粒，但是卻只能產生相當微量的共價閉合環狀去氧核醣核酸。相較之下，鴨子B型肝炎病毒(DHBV) ，它與B型肝炎病毒同屬，它能有效地在鳥類或人類的肝腫瘤細胞株中，產生共價閉合環狀去氧核醣核酸。所以，鴨子B型肝炎病毒是一個相當有價值的工具，可用來研究肝臟DNA病毒(hepadnavirus)的共價閉合環狀去氧核醣核酸的生成。在本次的計畫中，我們將追求四個主要的目標 :(1) 研究人類宿主的DNA修補機制在鴨子B型肝炎病毒生成共價閉合環狀去氧核醣核酸中的角色；(2)找出鴨子B型肝炎病毒基因體中，與共價閉合環狀去氧核醣核酸生成有關的必要基因片段；(3)建立肝臟DNA病毒(hepadnavirus)的共價閉合環狀去氧核醣核酸的報告載體，以用來研究共價閉合環狀去氧核醣核酸的生成；(4) 有系統的找出參與共價閉合環狀去氧核醣核酸生成的宿主因子。我們相信我們此項計畫的研究的成果，將有助於了解共價閉合環狀去氧核醣核酸的調控機轉，而且可能會提供新的治療策略，以根除慢性B型肝炎。<br> Abstract: Persistent covalently closed circular DNA (cccDNA) forms a major barrier to HBV eradication by current antiviral therapy with nucleos(t)ide analogues(NAs) or interferon. NAs can effectively suppress HBV replication via inhibition of viral reverse transcription, but rebound viremia is often observed following cessation of NA treatment. Therefore, understanding the mechanisms regulating HBV cccDNA formation is critical for management of HBV infection. Study of HBV cccDNA is hampered by lack of a convenient and tractable in vitro model for HBV cccDNA formation. Although HBV can generate infectious virions in human hepatoma cell lines, its cccDNA formation in these cell lines can be barely detected. In contrast, Duck HBV (DHBV) can efficiently generate cccDNA in human hepatoma cell lines. In this project, we, therefore, will specifically pursue four aims: (1) to investigate the role of a candidate gene FEN1 in cccDNA formation of DHBV (2) to compare and explore the mechanisms that differentially regulate cccDNA formation among different species of hepadnaviruses, HBV, DHBV and woodchuck hepatitis virus (WHV). (3) To establish a hepadnavirus cccDNA reporter cell line for cccDNA formation study and small molecule screening . (4) To identify host factors involving the formation of cccDNA. We believe that our potential findings should facilitate the research in HBV cccDNA and may provide novel strategies for eradication of chronic HBV infection.乙型肝炎乙型肝炎病毒鴨子乙型肝炎病毒共價閉鎖環狀去氧核醣核酸Chronic hepatitis BHepatitis B virusDuck hepatitis B viruscccDNA