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標題: | 光滑念珠菌SAGA 複合體於藥物耐受性及毒力之角色探討 The roles of SAGA complex in drug tolerance and virulence in Candida glabrata |
作者: | Sheng-Yung Yang 楊聖永 |
指導教授: | 陳穎練(Ying-Lien Chen) |
關鍵字: | 光滑念珠菌,SAGA 複合體,藥物耐受性,氧化壓力,毒力, Candida glabrata,SAGA complex,drug tolerance,oxidative stress,virulence, |
出版年 : | 2019 |
學位: | 碩士 |
摘要: | 光滑念珠菌為一種人體伺機性病原真菌,可附著在黏膜組織上並侵入血管造成系統性感染,其先天性耐藥性造成臨床治療上的困難。目前光滑念珠菌對於抗真菌藥物的耐受性、氧化壓力及毒力調控機制尚未有完整研究。SAGA 複合體藉由乙醯化組蛋白調控基因的表現,其組蛋白乙醯化模組主要由 Ada2、Ada3 及 Gcn5 組成。本實驗室之前人研究發現光滑念珠菌 ada2 突變株對於抗真菌藥物及干擾細胞壁之化合物的耐受性會下降,但此突變株之毒力卻增強。為了瞭解 Ada3 和 Gcn5 是否與 Ada2 有相似或是相異的功能,我們利用剔除個別基因、雙基因及三基因之突變株進行實驗。結果顯示單一基因(ADA3 或 GCN5)、雙基因以及三基因剔除之突變株中,組蛋白 (H3K9) 的乙醯化程度有顯著下降、生長速率較野生株緩慢、細胞壁的完整性下降、對於抗真菌藥物及氧化壓力的反應更敏感。有趣的是 gcn5 突變株對於影響細胞壁完整性之化合物、氧化壓力以及抗真菌藥物的反應較 ada2 或 ada3 突變株稍佳。此外,所有突變株入侵洋菜膠的能力增強且可促進毒力相關基因之表現。在小鼠系統性感染實驗中,ada3 和 gcn5 突變株接近高毒力,然而 ada3 gcn5 雙基因突變株呈現高毒力。同時,雙基因突變株 (ada2 ada3 和 ada2 gcn5) 以及三基因突變株 (ada2 ada3 gcn5) 亦表現高毒力。總結,Ada3 及 Gcn5 扮演與Ada2 相似的角色,參與調控 H3K9 乙醯化、氧化壓力反應與藥物耐受性,然而對於洋菜膠的侵入能力或是毒力卻是扮演抑制的功能。 Candida glabrata is an opportunistic human fungal pathogen and one of the non-albicans Candida species frequently isolated from patients with candidiasis. C. glabrata has intrinsic tolerance to antifungal drugs and ability to adhere on mucocutaneous surfaces, invade into bloodstream and cause systemic infection. However, the regulation of drug tolerance and virulence of C. glabrata remains elusive. SAGA (Spt-Ada-Gcn5 acetyltransferase) complex controls gene expression by regulating histone acetylation through the histone acetylation module (HAT) Ada2-Ada3-Gcn5. Our previous study showed that ada2 mutant is hypervirulence but decreases tolerance to antifungal drugs (i.e., azoles, echinocandins and polyene) and cell wall perturbing agents (i.e., calcofluor white, Congo red and SDS). This study further characterizes the functions of Ada3 and Gcn5 in C. glabrata. We found that ada3, gcn5, double or triple mutants in HAT module resulted in decreased level of acetylation on H3K9, slower growth, decreased antifungal drugs tolerance and oxidative stress response, while gcn5 mutant exhibited intermediate growth between the wild type and ada2 or ada3 mutant. In addition, HAT mutants increased agar invasion and expression of virulence associated genes. The ada3 and gcn5 mutants exhibited marginal hypervirulence, while double mutant (ada3 gcn5) showed hypervirulence in a murine model of systemic infection. Meanwhile, HAT double mutants (ada2 ada3 and ada2 gcn5) and triple mutant (ada2 ada3 gcn5) were hypervirulence. In conclusions, C. glabrata Ada3 and Gcn5 play similar roles as Ada2, regulating acetylation of H3K9, drug and oxidative stress tolerance and virulence. |
URI: | http://tdr.lib.ntu.edu.tw/handle/123456789/607 |
DOI: | 10.6342/NTU202000341 |
全文授權: | 同意授權(全球公開) |
顯示於系所單位: | 植物病理與微生物學系 |
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