Substrate-Induced Transcriptional Activation of the MoCel7C Cellulase Gene Is Associated with Methylation of Histone H3 at Lysine 4 in the Rice Blast Fungus Magnaporthe oryzae
Substrate-Induced Transcriptional Activation of the MoCel7C Cellulase Gene Is Associated with Methylation of Histone H3 at Lysine 4 in the Rice Blast Fungus Magnaporthe oryzae
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DOI：
10.1128/aem.02082-13
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发表时间：
2013-11-01
影响因子：
4.4
通讯作者：
Nakayashiki, Hitoshi
中科院分区：
文献类型：
--
作者：
Ba Van Vu;Kieu Thi Minh Pham;Nakayashiki, Hitoshi
研究了编码纤维素酶的稻瘟病菌基因（我们将其命名为MoCel7C（MGG_14954））的底物依赖性调控机制。在转移到含有2%羧甲基纤维素（CMC）的培养基后16至24小时，MoCel7C转录物的水平显著增加超过1，000倍，而在常规丰富培养基中水平非常低或检测不到。绿色荧光蛋白报告基因分析表明，MoCel7C启动子被大于五聚体的纤维寡糖激活。CMC诱导的MoCel7C启动子的激活被葡萄糖和纤维二糖抑制。染色质免疫沉淀试验表明，组蛋白H3甲基化赖氨酸4（H3K4）在MoCel7C基因座与CMC的基因激活。一致的是，在MoSET 1基因的敲除（KO）突变体中，CMC诱导的MoCel 7C基因激活急剧减弱，该基因编码一种催化M中H3 K4甲基化的组蛋白赖氨酸甲基转移酶。米。然而，有趣的是，在MoSET 1 KO突变体中，非诱导条件下的MoCel 7C转录水平显着增加，这表明MoSET 1直接或间接在MoCel 7C基因响应环境信号的激活和抑制中发挥作用。此外，构建了使用MoCel7C启动子的基因表达和沉默载体。
The mechanisms involved in substrate-dependent regulation of a Magnaporthe oryzae gene encoding a cellulase which we designate MoCel7C (MGG_14954) were investigated. The levels of MoCel7C transcript were dramatically increased more than 1,000-fold, 16 to 24 h after transfer to a medium containing 2% carboxymethylcellulose (CMC), while levels were very low or undetectable in conventional rich medium. Green fluorescent protein reporter assays showed that the MoCel7C promoter was activated by cello-oligosaccharides larger than a pentamer. CMC-induced activation of the MoCel7C promoter was suppressed by glucose and cellobiose. Chromatin immunoprecipitation assays revealed that histone H3 methylation on lysine 4 (H3K4) at the MoCel7C locus was associated with activation of the gene by CMC. Consistently, CMC-induced MoCel7C gene activation was drastically diminished in a knockout (KO) mutant of the MoSET1 gene, which encodes a histone lysine methyltransferase that catalyzes H3K4 methylation in M. oryzae. Interestingly, however, MoCel7C transcript levels under noninducing conditions were significantly increased in the MoSET1 KO mutant, suggesting that MoSET1 directly or indirectly plays a role in both activation and suppression of the MoCel7C gene in response to environmental signals. In addition, gene expression and silencing vectors using the MoCel7C promoter were constructed.