A gain-of-function mutation in the transcription factor Upc2p causes Upregulation of ergosterol biosynthesis genes and increased Fluconazole resistance in a clinical Candida albicans isolate
A gain-of-function mutation in the transcription factor Upc2p causes Upregulation of ergosterol biosynthesis genes and increased Fluconazole resistance in a clinical Candida albicans isolate
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DOI：
10.1128/ec.00103-08
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发表时间：
2008-07-01
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影响因子：
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通讯作者：
Rogers, P. David
中科院分区：
文献类型：
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作者：
Dunkel, Nico;Liu, Teresa T.;Rogers, P. David
在致病性酵母菌白色念珠菌中，锌簇转录因子Upc2p已被证明在暴露于唑类抗真菌剂时调节ERG 11和参与麦角固醇生物合成的其他基因的表达。ERG11编码羊毛甾醇脱甲基酶，这类抗真菌的靶酶。UPC 2的过表达降低唑类药物的敏感性，而其破坏导致对唑类药物的过敏性和外源甾醇的积累减少。ERG 11的过表达导致羊毛甾醇脱甲基酶的产生增加，这有助于临床分离的C.白色念珠菌，但其机制尚未确定。使用全基因组基因表达谱分析，我们发现UPC 2和其他基因参与麦角固醇生物合成协同上调与ERG 11在氟康唑耐药的临床分离株相比，从同一患者匹配的敏感分离株。这些分离株的UPC 2等位基因的序列分析显示，耐药分离株包含一个UPC 2等位基因中的一个单核苷酸取代，导致在编码的蛋白质中的G648D交换。将突变的等位基因引入药物敏感菌株导致ERG 11的组成性上调和对氟康唑的耐药性增加。通过比较氟康唑耐药分离株和携带野生型和突变UPC 2等位基因的菌株的基因表达谱，我们确定了由Upc2p控制的靶基因。在此，我们首次发现UPC 2的功能获得性突变导致ERG 11表达增加，并使临床分离的念珠菌对氟康唑产生耐药性。白色念珠菌。
In the pathogenic yeast Candida albicans, the zinc cluster transcription factor Upc2p has been shown to regulate the expression of ERG11 and other genes involved in ergosterol biosynthesis upon exposure to azole antifungals. ERG11 encodes lanosterol demethylase, the target enzyme of this antifungal class. Overexpression of UPC2 reduces azole susceptibility, whereas its disruption results in hypersusceptibility to azoles and reduced accumulation of exogenous sterols. Overexpression of ERG11 leads to the increased production of lanosterol demethylase, which contributes to azole resistance in clinical isolates of C. albicans, but the mechanism for this has yet to be determined. Using genome-wide gene expression profiling, we found UPC2 and other genes involved in ergosterol biosynthesis to be coordinately upregulated with ERG11 in a fluconazole-resistant clinical isolate compared with a matched susceptible isolate from the same patient. Sequence analysis of the UPC2 alleles of these isolates revealed that the resistant isolate contained a single-nucleotide substitution in one UPC2 allele that resulted in a G648D exchange in the encoded protein. Introduction of the mutated allele into a drug-susceptible strain resulted in constitutive upregulation of ERG11 and increased resistance to fluconazole. By comparing the gene expression profiles of the fluconazole-resistant isolate and of strains carrying wild-type and mutated UPC2 alleles, we identified target genes that are controlled by Upc2p. Here we show for the first time that a gain-of-function mutation in UPC2 leads to the increased expression of ERG11 and imparts resistance to fluconazole in clinical isolates of C. albicans.