Yan Hongbo, Zhao Yunying, Jiang Linghuo
The National Engineering Laboratory for Cereal Fermentation Technology, School of Biotechnology, Jiangnan University, Wuxi, China.
FEMS Yeast Res. 2014 Jun;14(4):614-23. doi: 10.1111/1567-1364.12148. Epub 2014 Mar 26.
The activated retrograde (RTG) pathway controls transcription of target genes through a heterodimer of transcription factors, Rtg1 and Rtg3, in Saccharomyces cerevisiae. Here, we have identified the sole homologous gene CaRTG3 that encodes a protein of 520 amino acids with characteristics of the basic helix-loop-helix/leucine zipper (bHLH/Zip) family in Candida albicans. Deletion of CaRTG3 results in C. albicans cells being sensitive to high concentrations of calcium and lithium cations as well as sodium dodecyl sulfate and activates the calcium/calcineurin signaling pathway in C. albicans cells. CaRTG3 is also involved in the tolerance of C. albicans cells to the antifungal drugs azoles and terbinafine, but not to the antifungal drugs casponfungin and amphotericin B as well as the cell-wall-damaging reagents Calcoflour White and Congo red. In contrast to ScRtg3, CaRtg3 is not involved in the osmolar response and is constitutively localized in the nucleus. However, deletion of CaRTG3 results in a delay in serum-induced filamentation of C. albicans cells. Therefore, CaRtg3 plays a role in tolerance to cations and antifungal drugs as well as serum-induced filamentation in C. albicans.
在酿酒酵母中，激活的逆向（RTG）途径通过转录因子Rtg1和Rtg3的异二聚体控制靶基因的转录。在此，我们鉴定出了白色念珠菌中唯一的同源基因CaRTG3，它编码一个含有520个氨基酸的蛋白质，具有碱性螺旋-环-螺旋/亮氨酸拉链（bHLH/Zip）家族的特征。CaRTG3的缺失导致白色念珠菌细胞对高浓度的钙和锂阳离子以及十二烷基硫酸钠敏感，并激活白色念珠菌细胞中的钙/钙调神经磷酸酶信号通路。CaRTG3还参与白色念珠菌细胞对唑类和特比萘芬等抗真菌药物的耐受性，但不参与对卡泊芬净和两性霉素B等抗真菌药物以及细胞壁损伤试剂荧光增白剂和刚果红的耐受性。与ScRtg3不同，CaRtg3不参与渗透压反应，而是组成性地定位于细胞核中。然而，CaRTG3的缺失导致白色念珠菌细胞血清诱导的丝状化延迟。因此，CaRtg3在白色念珠菌对阳离子和抗真菌药物的耐受性以及血清诱导的丝状化中发挥作用。
