Browsing by Author "Tseng, Kuo-Yun"

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Cph1p negatively regulates MDR1 involved in drug resistance in Candida albicans
(2015-06-01)
Lo, Hsiu Jung
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Tseng, Kuo-Yun
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Kao, Yeong-Yi
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Tsao, Ming-Yang
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Lo, Han-Lun
The cph1/cph1 efg1/efg1 double mutant in Candida albicans is defective in filamentous growth and is avirulent in a mouse model. We previously reported that Efg1p but not Cph1p is involved in drug resistance by negatively regulating ERG3 in C. albicans. In the current study, we have found that overexpression of 0411 in Saccharomyces cerevisiae increases susceptibility to the antifungal drug fluconazole. Furthermore, in C. albicans, null mutation of 0411 increased the expression of MDR1 as well as decreased susceptibility to fluconazole and voriconazole but not to amphotericin B. These findings indicate that although Efg1p and Cph1p may have the same effects on virulence, they have opposite effects on drug resistance in C. albicans. (C) 2015 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.
Rep1p negatively regulating MDR1 efflux pump involved in drug resistance in Candida albicans
(2009-09-01)
Chen, Chia-Geun
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Yang, Yun-Liang
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Tseng, Kuo-Yun
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Shih, Hsin-I
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Liou, Ci-Hong
Overexpression of MDR1 efflux pump is a major mechanism contributing to drug resistance in Candida albicans, the most common human fungal pathogen. To elucidate the regulatory pathway of drug resistance, we have identified a negative regulator of MDR1 and named it Regulator of Efflux Pump 1 (REP1). Overexpression of REPI in Saccharomyces cerevisiae increased susceptibility to fluconazole. Furthermore, null mutations on REP1 decreased the susceptibility to antifungal drugs in C albicans resulting from increased expression of MDR1 mRNA. Hence, Rep1p is involved in drug resistance by negatively regulating MDR1 in C albicans. (c) 2009 Elsevier Inc. All rights reserved.
The DNA-binding domain of CaNdt80p is required to activate CDR1 involved in drug resistance in Candida albicans
(2006-10-01)
Wang, Jang-Shiun
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Yang, Yun-Liang
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Wu, Chin-Jung
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Ouyang, Karen J.
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Tseng, Kuo-Yun
CaNdt80p, the Candida albicans homologue of the Saccharomyces cerevisiae transcription factor ScNdt80p, has been identified as a positive regulator of CDR1, which encodes an eff lux pump involved in drug resistance in C. albicans. To investigate the involvement of the putative DNA-binding domain of CaNdt80p in drug resistance, chimeras of CaNdt80p and ScNdt80p were constructed. Interestingly, the DNA-binding domain of ScNdt80p could functionally complement that of CaNdt80p to activate CDR1p-lacZ in S. cerevisiae. Consistently, CaNdt80p containing a mutation in the DNA-binding domain failed to activate CDR1p-lacZ in S. cerevisiae. Furthermore, a copy of CaNDT80 with the same mutation also failed to complement the drug-sensitive phenotype caused by a null mutation in C. albicans. Thus, the DNA-binding domain of CaNdt80p is critical for its function in drug resistance in C. albicans.