Institute of Molecular Infection Biology, University of Würzburg, Würzburg, Germany.
Department of Pharmacy and Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee, USA.
mSphere. 2024 Jul 30;9(7):e0027024. doi: 10.1128/msphere.00270-24. Epub 2024 Jun 11.
Zinc cluster transcription factors (ZCFs) are a family of transcription regulators that are almost exclusively found in the fungal kingdom. Activating mutations in the ZCFs Mrr1, Tac1, and Upc2 frequently cause acquired resistance to the widely used antifungal drug fluconazole in the pathogenic yeast . Similar to a hyperactive Tac1, a constitutively active form of the ZCF Znc1 causes increased fluconazole resistance by upregulating the multidrug efflux pump-encoding gene . Hyperactive forms of both Tac1 and Znc1 also cause overexpression of , which encodes a seven-transmembrane receptor protein involved in the regulation of asymmetric lipid distribution in the plasma membrane. expression is also upregulated by miltefosine, an antiparasitic drug that is active against fungal pathogens and considered for treatment of invasive candidiasis, and Δ mutants are hypersensitive to miltefosine. We found that activated forms of both Tac1 and Znc1 confer increased miltefosine resistance, which was dependent on whereas was dispensable. Intriguingly, the induction of expression by miltefosine depended on Znc1, but not Tac1, in contrast to the known Tac1-dependent upregulation by fluphenazine. In line with this observation, Δ mutants were hypersensitive to miltefosine, whereas Δ mutants showed wild-type tolerance. Forced expression of reverted the hypersensitivity of Δ mutants, demonstrating that the hypersensitivity was caused by the inability of the mutants to upregulate in response to the drug. These findings establish Znc1 as a key regulator of miltefosine-induced expression that is important for wild-type miltefosine tolerance.
Transcription factors are central regulators of gene expression, and knowledge about which transcription factor regulates specific genes in response to a certain signal is important to understand the behavior of organisms. In the pathogenic yeast , the gene is required for wild-type tolerance of miltefosine, an antiparasitic drug that is considered for treatment of invasive candidiasis. Activated forms of the transcription factors Tac1 and Znc1 cause constitutive overexpression of and thereby increased miltefosine resistance, but only Tac1 mediates upregulation of in response to the known inducer fluphenazine. expression is also induced by miltefosine, and we found that this response depends on Znc1, whereas Tac1 is dispensable. Consequently, Δ mutants were hypersensitive to miltefosine, whereas Δ mutants showed wild-type tolerance. These findings demonstrate that Znc1 is the key regulator of expression in response to miltefosine that is important for wild-type miltefosine tolerance.
锌簇转录因子（ZCFs）是一类转录调节因子，几乎只存在于真菌界。在致病性酵母中，ZCFs Mrr1、Tac1 和 Upc2 的激活突变常导致对广泛使用的抗真菌药物氟康唑产生获得性耐药。类似于活性增强的 Tac1，组成型激活形式的 ZCF Znc1 通过上调多药外排泵编码基因 ，导致氟康唑耐药性增加。活性增强的 Tac1 和 Znc1 也导致 表达上调， 编码一种七跨膜受体蛋白，参与质膜中不对称脂质分布的调节。 表达也被抗寄生虫药物米替福新上调，米替福新对真菌病原体有效，被认为可用于治疗侵袭性念珠菌病，Δ突变体对米替福新敏感。我们发现，Tac1 和 Znc1 的激活形式赋予了对米替福新的耐药性增加，这依赖于 ，而 则是可有可无的。有趣的是，米替福新诱导 表达依赖于 Znc1，但不依赖于 Tac1，与已知的 Tac1 依赖的 fluphenazine 诱导 上调形成对比。与这一观察结果一致，Δ突变体对米替福新敏感，而 Δ突变体表现出野生型耐受性。 过表达使 Δ突变体的敏感性逆转，表明突变体无法响应药物上调 是导致其敏感性的原因。这些发现确立了 Znc1 作为米替福新诱导的 表达的关键调节剂，这对于野生型米替福新耐受性很重要。
转录因子是基因表达的核心调节剂，了解哪些转录因子响应特定信号调节特定基因对于理解生物体的行为很重要。在致病性酵母 中， 基因对于米替福新的野生型耐受性是必需的，米替福新被认为可用于治疗侵袭性念珠菌病。转录因子 Tac1 和 Znc1 的激活形式导致 组成型过表达，从而导致米替福新耐药性增加，但只有 Tac1 介导对已知诱导剂 fluphenazine 的 上调。 表达也被米替福新诱导，我们发现这种反应依赖于 Znc1，而 Tac1 则可有可无。因此，Δ突变体对米替福新敏感，而 Δ突变体表现出野生型耐受性。这些发现表明，Znc1 是米替福新诱导的 表达的关键调节剂，对于野生型米替福新耐受性很重要。
