Antsotegi-Uskola Martzel, Markina-Iñarrairaegui Ane, Ugalde Unai
Microbial Biochemistry Laboratory, Department of Applied Chemistry, Faculty of Chemistry, University of the Basque CountrySan Sebastian, Spain.
Front Microbiol. 2017 May 30;8:912. doi: 10.3389/fmicb.2017.00912. eCollection 2017.
Copper homeostasis has been extensively studied in mammals, bacteria, and yeast, but it has not been well-documented in filamentous fungi. In this report, we investigated the basis of copper tolerance in the model fungus . Three genes involved in copper homeostasis have been characterized. First, the ortholog of gene encoding a P-type ATPase was identified. The phenotype of deletion led to a severe sensitivity to Cu toxicity and a characteristic morphological growth defect in the presence of high copper concentration. CrpA displayed some promiscuity regarding metal species response. The expression pattern of showed an initial strong elevation of mRNA and a low continuous gene expression in response to long term toxic copper levels. Coinciding with maximum protein expression level, CrpA was localized close to the cellular surface, however protein distribution across diverse organelles suggests a complex regulated trafficking process. Secondly, gene, encoding a transcription factor was identified and deleted, resulting in an even more extreme copper sensitivity than the ΔcrpA mutant. Protein expression assays corroborated that AceA was necessary for metal inducible expression of CrpA, but not CrdA, a putative metallothionein the function of which has yet to be elucidated.
铜稳态在哺乳动物、细菌和酵母中已得到广泛研究，但在丝状真菌中尚未有充分记录。在本报告中，我们研究了模式真菌中铜耐受性的基础。已鉴定出三个参与铜稳态的基因。首先，鉴定出编码P型ATP酶的基因的直系同源物。缺失该基因的表型导致对铜毒性的严重敏感性以及在高铜浓度下出现特征性的形态生长缺陷。CrpA在金属种类反应方面表现出一定的混杂性。其表达模式显示，mRNA最初强烈升高，而在长期有毒铜水平下基因表达持续较低。与最大蛋白表达水平一致，CrpA定位于靠近细胞表面，但跨不同细胞器的蛋白分布表明存在复杂的调控运输过程。其次，鉴定并缺失了编码转录因子的基因，其导致的铜敏感性比ΔcrpA突变体更为极端。蛋白质表达分析证实，AceA对于CrpA的金属诱导表达是必需的，但对于CrdA（一种功能尚未阐明的假定金属硫蛋白）则不是必需的。
