The bZIP Transcription Factor MeaB Mediates Nitrogen Metabolite Repression at Specific Loci
The bZIP Transcription Factor MeaB Mediates Nitrogen Metabolite Repression at Specific Loci
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bZIP 转录因子 MeaB 介导特定位点的氮代谢物抑制
DOI：
10.1128/ec.00146-10
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发表时间：
2010
期刊：
影响因子：
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通讯作者：
B. Tudzynski
中科院分区：
文献类型：
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作者：
Dominik Wagner;Anne Schmeinck;Magdalena Moś;I. Morozov;M. Caddick;B. Tudzynski
摘要在Fujikuroi镰刀菌中，Bikverin(BIK)的生物合成受到氮素的抑制。与大多数受氮代谢抑制的基因不同，已经证明BIK生物合成基因的转录不是区域依赖的。为了寻找可能参与氮素调控的其他转录因子，我们克隆并鉴定了编码bZIP转录因子的nidulansmeaB的同源基因。FujikuroimeaB有两个转录本：在氮素充足条件下以大转录本(MeaBL)为主，在氮限制条件下以小转录本(MeaBS)为主，这是一种区域依赖的方式。在氮充足的条件下，MeaB在Fujikuroi和A.nidulans中都被特异性地转运到细胞核。缺失meaB导致部分氮素调控基因上调，但只有在ΔmeaBΔ区的双突变才能在谷氨酰胺存在下显著上调bikverin基因。这些数据表明，MeaB和AREA协同介导氮代谢产物的抑制，更重要的是，MeaB不依赖于AREA，可以在特定的位点上介导氮代谢产物的抑制。
ABSTRACT In Fusarium fujikuroi, bikaverin (BIK) biosynthesis is subject to repression by nitrogen. Unlike most genes subject to nitrogen metabolite repression, it has been shown that transcription of bik biosynthetic genes is not AreA dependent. Searching for additional transcription factors that may be involved in nitrogen regulation, we cloned and characterized the orthologue of Aspergillus nidulansmeaB, which encodes a bZIP transcription factor. Two transcripts are derived from F. fujikuroimeaB: the large transcript (meaBL) predominates under nitrogen-sufficient conditions and the smaller transcript (meaBS) under nitrogen limitation, in an AreA-dependent manner. MeaB is specifically translocated to the nucleus under nitrogen-sufficient conditions in both F. fujikuroi and A. nidulans. Deletion of meaB resulted in partial upregulation of several nitrogen-regulated genes, but only in the ΔmeaB ΔareA double mutant were the bikaverin genes significantly upregulated in the presence of glutamine. These data demonstrate that MeaB and AreA coordinately mediate nitrogen metabolite repression and, importantly, that independently of AreA, MeaB can mediate nitrogen metabolite repression at specific loci in F. fujikuroi.