探討剔除白色念珠菌CaORF19.5285 與CaORF19.5285 對白色念珠菌的型態變化及其性狀

Abstract

白色念珠菌是人體伺機型真菌，共生於人體的腸胃道、口腔黏膜組織、陰道，對於免疫力不全的人容易造成感染，嚴重時可導致致命的系統性感染。具有型態變換能力的白色念珠菌具有較強的致病力，已找到EFG1 及CPH1 兩個相關的轉錄因子進行進一步研究。

前人用Microarray 的方式比較SC5314 野生型JKC19 (cph1/cph1)及HLC52 (efg1/efg1)在藥物出現的條件下找出表現差異的基因。其中我選擇CaORF19.1105、CaORF19.5285 這兩個基因做為我研究的目標。CaORF19.1105 是一個未知的基因，BLAST 的結果與轉錄因子相似，預期與形態變化有關。CaORF19.5285 與啤酒酵母的PST2 基因序列相近，有研究指出PST2和氧化壓力有關。

使用SAT1 flipper cassette 以同源置換做為基因剔除手段將CaORF19.1105、CaORF19.5285 分別製備基因剔除株。型態變化相關測試的結果顯示在所用的條件下，基因剔除株仍然有型態轉變的能力，表示這兩個基因的剔除對型態轉變並沒有影響。在氧化測試的結果中CaORF19.5285基因剔除株與wild type 表現一致，顯示基因的剔除對於氧化壓力的抵抗力也沒有影響。

Candida albicans is an opportunistic pathogen, living in human oral cavity gastrointestinal tract and vaginal. For immunocompromised host, it had chance to cause lethal system infection. Candida albicans with the ability to switch morphology had high virulence. Previous study found that EFG1 and CPH1, two transcription factor, are related to morphology ability.

Previous research using Microarray method to find out the gene related to morphology and drug resistance by compare wild type SC5314, JKC19 (cph1/cph1) and HLC52 (efg1/efg1). From those result, I chose CaORF19.1105 and CaORF19.5285 as my research target. CaORF19.1105 is gene with un-know function but suspected to be involved with phenotype switching. Blast result also showed that it may be a transcription factor. CaORF19.5285 is similar to PST2 gene, a Saccharomyces cerevisiae gene which may associate to ROS resistance.

I Used SAT1 flipper cassette to knock-out CaORF19.1105 and CaORF19.5285 gene. Tests show both null mutants still can switch morphology. In oxygen stress test, CaORF19.5285 null mutant shows no difference when compared to the wild type. Those result mean there two genes do not influence the morphology, and CaORF19.5285 null mutant has no effect to ROS.