AtrR转录调节因子保守C末端区域的缺失导致靶基因表达出现基因特异性缺陷。
Loss of a conserved C-terminal region of the AtrR transcriptional regulator leads to a gene-specific defect in target gene expression.
作者信息
Ror Shivani, Stamnes Mark A, Moye-Rowley W Scott
机构信息
Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA.
出版信息
bioRxiv. 2024 May 23:2024.05.22.595332. doi: 10.1101/2024.05.22.595332.
Treatment of fungal infections associated with the filamentous fungus is becoming more problematic as this organism is developing resistance to the main chemotherapeutic drug at an increasing rate. Azole drugs represent the current standard-of-care in treatment of aspergillosis with this drug class acting by inhibiting a key step in biosynthesis of the fungal sterol ergosterol. Azole compounds block the activity of the lanosterol α-14 demethylase, encoded by the gene. A common route of azole resistance involves an increase in transcription of . This transcriptional increase requires the function of a Zn2Cys6 DNA-binding domain-containing transcription activator protein called AtrR. AtrR was identified through its action as a positive regulator of expression of an ATP-binding cassette transporter (/ here called ). Using both deletion and alanine scanning mutagenesis, we demonstrate that a conserved C-terminal domain in is required for expression of but dispensable for transcription. This domain is also found in several other fungal pathogen AtrR homologues consistent with a conserved gene-selective function of this protein segment being conserved. Using RNA-seq, we find that this gene-specific transcriptional defect extends to several other membrane transporter-encoding genes including a second ABC transporter locus. Our data reveal that AtrR uses at least two distinct mechanisms to induce gene expression and that normal susceptibility to azole drugs cannot be provided by maintenance of wild-type expression of the ergosterol biosynthetic pathway when ABC transporter expression is reduced.
随着丝状真菌对主要化疗药物的耐药性不断增加,治疗与该丝状真菌相关的真菌感染变得越来越棘手。唑类药物是目前治疗曲霉病的标准治疗药物,这类药物通过抑制真菌甾醇麦角固醇生物合成中的关键步骤起作用。唑类化合物可阻断由 基因编码的羊毛甾醇α-14脱甲基酶的活性。唑类耐药的常见途径包括 转录增加。这种转录增加需要一种名为AtrR的含Zn2Cys6 DNA结合结构域的转录激活蛋白发挥作用。AtrR是通过其作为ATP结合盒转运蛋白(此处称为 )表达的正调控因子的作用而被鉴定出来的。通过缺失和丙氨酸扫描诱变,我们证明了 中一个保守的C末端结构域是 表达所必需的,但对 转录是可有可无的。在其他几种真菌病原体AtrR同源物中也发现了这个结构域,这与该蛋白质片段的保守基因选择性功能是一致的。使用RNA测序,我们发现这种基因特异性转录缺陷延伸到其他几个编码膜转运蛋白的基因,包括第二个ABC转运蛋白基因座。我们的数据表明,AtrR至少使用两种不同的机制来诱导基因表达,并且当ABC转运蛋白表达降低时,维持麦角固醇生物合成途径的野生型表达并不能保证对唑类药物的正常敏感性。