Characterization of the Aspergillus parasiticus niaD and niiA gene cluster
Characterization of the Aspergillus parasiticus niaD and niiA gene cluster
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DOI：
10.1007/s002940050102
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发表时间：
1996-06-01
期刊：
影响因子：
2.5
通讯作者：
Bennett, JW
中科院分区：
文献类型：
--
作者：
Chang, PK;Ehrlich, KC;Bennett, JW
寄生曲霉的硝酸盐还原酶基因（niaD）和亚硝酸盐还原酶基因（niiA）在一个1.6 kb的基因间区（niaD-niiA）呈簇状分布，并有差异转录。结果表明，寄生拟南芥硝酸根还原酶的氨基酸序列与其他曲霉属以及黄斑细螺旋菌、尖孢镰刀菌、藤黑赤霉素和粗神经孢子菌具有高度的同源性，特别是在钼、血红素和FAD的辅因子结合域。推导出的亚硝酸盐还原酶序列部分与拟南芥和草属植物同源。寄生蜂的niaD-niiA核苷酸序列与稻蚜的相同度为95%，表明二者亲缘关系密切。在寄生蜂niaD-niiA中发现了几个GATA基序，这些基序是寄生蜂氮代谢正作用全局调控蛋白NIT2的识别位点。在硝酸盐同化过程中，还鉴定出了两个回文序列TCCGCGGA和其他部分回文序列，这些回文序列与途径特异性调节蛋白N. crassa NIT4和A. nidulans NirA的靶位点相似。含有A. nidulans区域（NIT2等效区）锌指和相邻基本区的重组蛋白能够结合niaD-niiA中包含GATA基元的片段。这些结果表明，在曲霉中硝酸盐同化的催化和调控机制是保守的。
The nitrate reductase gene (niaD) and nitrite reductase gene (niiA) of Aspergillus parasiticus are clustered and are divergently transcribed from a 1.6-kb intergenic region (niaD-niiA). The deduced amino-acid sequence of the A. parasiticus nitrate reductase demonstrated a high degree of homology to those of other Aspergillus species, as well as to Leptosphaeria maculans, Fusarium oxysporum, Gibberella fujikuroi and Neurospora crassa, particularly in the cofactor-binding domains for molybdenum, heme and FAD. A portion of the deduced nitrite reductase sequence was homologous to those of A. nidulans and N. crassa. The nucleotide sequences in niaD-niiA of A. parasiticus and of A. oryzae were 95% identical, indicating that these two species are closely related. Several GATA motifs, the recognition sites for the N. crassa positive-acting global regulatory protein NIT2 in nitrogen metabolism, were found in A. parasiticus niaD-niiA. Two copies of the palindrome TCCGCGGA and other partial palindromic sequences similar to the target sites for the pathway specific regulatory proteins, N. crassa NIT4 and A. nidulans NirA, in nitrate assimilation, were also identified. A recombinant protein containing the A. nidulans AreA (the NIT2 equivalent) zinc finger and an adjacent basic region was able to bind to segments of niaD-niiA encompassing the GATA motifs. These results suggest that the catalytic and regulatory mechanisms of nitrate assimilation are well conserved in Aspergillus.