Copper-mediated reversal of defective laccase in a Deltavph1 avirulent mutant of Cryptococcus neoformans.
Copper-mediated reversal of defective laccase in a Deltavph1 avirulent mutant of Cryptococcus neoformans.
复制标题
铜介导的新生隐球菌 Deltavph1 无毒突变体中缺陷漆酶的逆转。
DOI：
10.1046/j.1365-2958.2003.03340.x
复制
发表时间：
2003
影响因子：
3.6
通讯作者：
Williamson,PeterR
中科院分区：
文献类型：
--
作者：
Zhu,Xudong;Gibbons,Jack;Zhang,Shirong;Williamson,PeterR
Previous studies have shown that a Δvph1 Cryptococcus neoformansmutant defective in vesicular acidification lacked several important virulence factors including a copper‐containing laccase and was avirulent in a mouse model. In the present studies, we characterized laccase transcription and protein production to obtain insights into the mechanism of thevph1mutation in this pathogen. Although transcription and protein expression were somewhat reduced, laccase protein was found to be successfully translated and correctly targeted to the cell wall in the Δvph1mutant as shown by Western blot and immuno‐electron microscopy, despite a complete lack of laccase activity. Laccase activity was substantially restored in metabolically active Δvph1cells at 30°C by addition of 100 µM copper sulphate. This restoration by copper was found to occur through both transcriptional and post‐translational mechanisms. Laccase transcriptional induction by copper was found to be dependent on enhancer region II within the 5′‐untranslated region ofCNLAC1. Copper was also found to restore partial activity to Δvph1cells at 0°C, suggesting that cell wall laccase was expressed in the mutant as an apo‐enzyme. Apo‐laccase restoration by copper was found to be facilitated by an acidic environment, consistent with a role for the vacuolar (H+)‐ATPase proton pump in copper assembly of laccase inC. neoformans.
