Lima Joel Fernandes, Malavazi Iran, von Zeska Kress Fagundes Marcia Regina, Savoldi Marcela, Goldman Maria Helena S, Schwier Elke, Braus Gerhard H, Goldman Gustavo Henrique
Faculdade de Ciências Farmacêuticas de Ribeirão Preto and Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, São Paulo, 1404-903 Brazil.
Genetics. 2005 Nov;171(3):1003-15. doi: 10.1534/genetics.105.041376. Epub 2005 Aug 3.
The signalosome (CSN) is a conserved multiprotein complex involved in regulation of eukaryotic development and is also required to activate ribonucleotide reductase for DNA synthesis. In Aspergillus nidulans, csnD/csnE are key regulators of sexual development. Here, we investigated whether the csnD/csnE genes are involved in the DNA damage response in this fungus. The growth of the csnD/csnE deletion mutants was reduced by subinhibitory concentrations of hydroxyurea, camptothecin, 4-nitroquinoline oxide, and methyl methanesulfonate. A. nidulans increases csnD/csnE mRNA levels when it is challenged by different DNA-damaging agents. There is no significant transcriptional induction of the csnE promoter fused with lacZ gene in the presence of DNA-damaging agents, suggesting that increased mRNA accumulation is due to increased mRNA stability. Septation was not inhibited in the csnD/csnE deletion mutants while DeltauvsB DeltacsnE presented an increase in septation upon DNA damage caused by methyl methanesulfonate, suggesting that uvsB(ATR) and csnE genetically interact during checkpoint-dependent inhibition of septum formation. The double DeltacsnD/DeltacsnE DeltanpkA mutants were more sensitive to DNA-damaging agents than were the respective single mutants. Our results suggest that csnD/csnE genes are involved in the DNA damage response and that NpkA and UvsB(ATR) genetically interact with the signalosome.
信号体（CSN）是一种保守的多蛋白复合体，参与真核生物发育的调控，并且在激活核糖核苷酸还原酶以进行DNA合成时也是必需的。在构巢曲霉中，csnD/csnE是有性发育的关键调节因子。在此，我们研究了csnD/csnE基因是否参与这种真菌的DNA损伤反应。csnD/csnE缺失突变体的生长受到亚抑制浓度的羟基脲、喜树碱、4-硝基喹啉氧化物和甲磺酸甲酯的抑制。当构巢曲霉受到不同的DNA损伤剂挑战时，其csnD/csnE mRNA水平会升高。在存在DNA损伤剂的情况下，与lacZ基因融合的csnE启动子没有明显的转录诱导，这表明mRNA积累的增加是由于mRNA稳定性的提高。在csnD/csnE缺失突变体中，隔膜形成没有受到抑制，而在甲磺酸甲酯引起的DNA损伤后，DeltauvsB DeltacsnE的隔膜形成增加，这表明uvsB（ATR）和csnE在依赖检查点的隔膜形成抑制过程中存在遗传相互作用。双突变体DeltacsnD/DeltacsnE DeltanpkA比各自的单突变体对DNA损伤剂更敏感。我们的结果表明，csnD/csnE基因参与DNA损伤反应，并且NpkA和UvsB（ATR）与信号体存在遗传相互作用。
