AtfA bZIP-type transcription factor regulates oxidative and osmotic stress responses in Aspergillus nidulans
AtfA bZIP-type transcription factor regulates oxidative and osmotic stress responses in Aspergillus nidulans
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DOI：
10.1007/s00438-010-0513-z
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发表时间：
2010-03-01
影响因子：
3.1
通讯作者：
Pocsi, Istvan
中科院分区：
文献类型：
--
作者：
Balazs, Anita;Pocsi, Imre;Pocsi, Istvan
该研究的目的是证明 bZIP 型转录因子 AtfA 与裂殖酵母的直系同源“通用”转录因子 Atf1 类似，可调节构巢曲霉中不同类型的应激反应。在粟酒裂殖酵母 Delta atf1 突变体中异源表达 atfA 可将表面培养物中裂殖酵母的渗透胁迫耐受性恢复至与 atf1 基因互补研究中记录的相同水平，并且在深层培养物中也实现了渗透和氧化胁迫敏感表型的部分互补。因此，AtfA 是裂殖酵母 Atf1 的真正功能直系同源物。 RT-PCR 实验表明，氧化（例如过氧化氢酶 B）和渗透（例如 3-磷酸甘油脱氢酶 B）应激防御系统的元件均受到 AtfA 以应激类型特异性方式进行转录调节。 atfA 的缺失导致氧化应激敏感表型，而真菌的高渗透压应激敏感性并未受到显着影响。在构巢曲霉中，细胞的谷胱甘肽/谷胱甘肽二硫化物氧化还原状态以及细胞凋亡和自溶似乎是由 AtfA 以外的调控元件控制的。总之，曲霉和裂殖酵母的应激反应的协调具有几个共同特征，但需要进一步的研究来回答裂殖酵母样核心环境应激反应是否也在真子囊菌属曲霉属中起作用的重要问题。
The aim of the study was to demonstrate that the bZIP-type transcription factor AtfA regulates different types of stress responses in Aspergillus nidulans similarly to Atf1, the orthologous 'all-purpose' transcription factor of Schizosaccharomyces pombe. Heterologous expression of atfA in a S. pombe Delta atf1 mutant restored the osmotic stress tolerance of fission yeast in surface cultures to the same level as recorded in complementation studies with the atf1 gene, and a partial complementation of the osmotic and oxidative-stress-sensitive phenotypes was also achieved in submerged cultures. AtfA is therefore a true functional ortholog of fission yeast's Atf1. As demonstrated by RT-PCR experiments, elements of both oxidative (e.g. catalase B) and osmotic (e.g. glycerol-3-phosphate dehydrogenase B) stress defense systems were transcriptionally regulated by AtfA in a stress-type-specific manner. Deletion of atfA resulted in oxidative-stress-sensitive phenotypes while the high-osmolarity stress sensitivity of the fungus was not affected significantly. In A. nidulans, the glutathione/glutathione disulfide redox status of the cells as well as apoptotic cell death and autolysis seemed to be controlled by regulatory elements other than AtfA. In conclusion, the orchestrations of stress responses in the aspergilli and in fission yeast share several common features, but further studies are needed to answer the important question of whether a fission yeast-like core environmental stress response also operates in the euascomycete genus Aspergillus.