Negative Roles of a Novel Nitrogen Metabolite Repression-Related Gene, TAR1, in Laccase Production and Nitrate Utilization by the Basidiomycete Cryptococcus neoformans
Negative Roles of a Novel Nitrogen Metabolite Repression-Related Gene, TAR1, in Laccase Production and Nitrate Utilization by the Basidiomycete Cryptococcus neoformans
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DOI：
10.1128/aem.00708-09
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发表时间：
2009-11-01
影响因子：
4.4
通讯作者：
Zhu, Xudong
中科院分区：
文献类型：
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作者：
Jiang, Nan;Xiao, Dongguang;Zhu, Xudong
多铜氧化酶漆酶广泛存在于真菌中，具有重要的工业价值。关于在担子菌酵母新型隐球菌中产生漆酶的一个难题是，它被高温抑制（例如，例如，在一个实施例中，37摄氏度）。在本文中，我们报告的氮代谢抑制相关基因，TAR 1，这是负责漆酶抑制的鉴定。TAR 1的破坏导致LAC 1 mRNA水平在37 ℃下显著增加。推定的蛋白质Tar 1与来自粗糙脉孢菌和构巢曲霉的氮代谢物阻遏物Nmr 1和NmrA分别具有中等水平的相似性。同样，Tar 1在硝酸盐利用中具有负面作用。此外，Tar 1的结构是独特的。Tar 1缺乏Nmr 1和NmrA的长C末端区域。它包含典型的Rossmann折叠基序GlyXXGlyXXGly，而Nmr 1和NmrA在Gly位置具有可变残基。有趣的是，TAR 1的启动子区含有三个TTC/GAA重复序列，这可能是热休克因子（Hsf）结合位点，这意味着Hsf在漆酶抑制中起作用。TAR 1介导的温度相关的抑制LAC 1表明漆酶调节的新机制和NMR蛋白的新功能。我们的工作可能有助于促进漆酶活性的工业。
The multicopper oxidase laccase is widespread in fungi and has great industrial importance. One puzzle regarding laccase production in the basidiomycetous yeast Cryptococcus neoformans is that it is inhibited by high temperature (e. g., 37 degrees C). In this paper, we report identification of a nitrogen metabolite repression-related gene, TAR1, which is responsible for laccase repression. Disruption of TAR1 results in a significant increase in the level of LAC1 mRNA at 37 degrees C. The putative protein Tar1 shares a moderate level of similarity with the nitrogen metabolite repressors Nmr1 and NmrA from Neurospora crassa and Aspergillus nidulans, respectively. Likewise, Tar1 has a negative role in the utilization of nitrate. Furthermore, the structure of Tar1 is unique. Tar1 lacks the long C-terminal region of Nmr1 and NmrA. It contains the canonical Rossmann fold motif, GlyXXGlyXXGly, whereas Nmr1 and NmrA have variable residues at the Gly positions. Interestingly, the promoter region of TAR1 contains three TTC/GAA repeats which are likely the heat shock factor (Hsf) binding sites, implying that Hsf has a role in laccase inhibition. TAR1 mediation of temperature-associated repression of LAC1 suggests a novel mechanism of laccase regulation and a new function for Nmr proteins. Our work may be helpful for industry in terms of promotion of laccase activity.