Regulation of Manganese Peroxidase Gene Expression

9405978金白色腐担子菌真菌黄孢原毛革菌的木质素降解系统（LDS）能够降解植物细胞壁聚合物、木质素和一系列芳香族污染物。这种非特异性氧化系统的主要成分是两种细胞外含血红素的过氧化物酶，锰过氧化物酶（MnP）和木质素过氧化物酶（LiP）。LDS在次级代谢生长期间表达，其起始由限制营养氮引发。Mn离子、热激和化学胁迫也在基因转录水平上调节MNP的表达。该项目的主要目标是在分子水平上阐明mnp基因转录的这些特定机制。锰，热休克和H2O2调节的个别mnp基因将分析在氮和碳限制的条件下。定点突变，缺失分析和合成启动子元件被用来确定Mn和热休克调节所需的顺式作用序列。DNA酶I足迹法和凝胶迁移率变动测定法将用于测定推定的DNA结合转录因子。将比较Mn和热休克诱导的mnp mRNA，并检查转录后Mn需求的可能性。真菌黄孢原毛平革菌的木质素降解系统（LDS）能够降解植物细胞壁聚合物、木质素和一系列芳香族污染物。该项目的主要目标是确定是什么导致参与这种降解的酶的基因被打开和关闭。这项工作可能最终有助于从环境中去除污染物。

9405978 Gold The lignin degradative system (LDS) of the white rot basidiomycetous fungus Phanerochaete chrysosporium is capable of degrading the plant cell wall polymer, lignin, and a range of aromatic pollutants. The major components of this nonspecific oxidative system are two extracellular heme-containing peroxidases, manganese peroxidase (MnP) and lignin peroxidase (LiP). The LDS is expressed during secondary metabolic growth, the onset of which is triggered by limiting nutrient nitrogen. MnP expression also is regulated at the level of gene transcription by Mn ion and by heat shock and chemical stress. The primary goal of the project is to elucidate on the molecular level these specific mechanisms of mnp gene transcription. Mn, heat shock and H2O2 regulation of individual mnp genes will be analyzed under conditions of nitrogen and carbon limitation. Site-directed mutagenesis, deletion analysis and synthetic promoter elements are being used to identify the cis-acting sequences required for Mn and heat shock regulation. DNaseI footprinting and gel mobility shift assays will be used to assay putative DNA-binding transcription factors. Mn and heat shock-induced mnp mRNAs will be compared and the possibility of a post-transcriptionial Mn requirement will be examined. %%% The lignin degradative system (LDS) of the fungus Phanerochaete chrysosporium is capable of degrading the plant cell wall polymer, lignin, and a range of aromatic pollutants. The primary goal of this project is to determine what causes the genes for the enzymes involved in this degradation to be turned on and off. This work may ultimately help in the removal of pollutants from the environment.