A Novel Transcriptional Repressor, Rhit, Is Involved in Heat-Inducible and Age-Dependent Expression of Mpv17-Like Protein, a Participant in Reactive Oxygen Species Metabolism
A Novel Transcriptional Repressor, Rhit, Is Involved in Heat-Inducible and Age-Dependent Expression of Mpv17-Like Protein, a Participant in Reactive Oxygen Species Metabolism
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DOI：
10.1128/mcb.01025-09
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发表时间：
2010-05-15
影响因子：
5.3
通讯作者：
Yasuda, Toshihiro
中科院分区：
文献类型：
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作者：
Iida, Reiko;Ueki, Misuzu;Yasuda, Toshihiro
mpv17样蛋白（M-LP）是一种被认为参与活性氧代谢的蛋白。小鼠中的两种M-LP异构体M-LPS和M-LPL是由启动子的替代使用产生的。6周后，M-LPS仅在肾脏中表达，而M-LPL则普遍表达。为了阐明M-LPS表达的分子基础，我们在M-LPS的启动子区域寻找顺式调控元件，发现热休克元件半位点为阳性元件，Tramtrack 69K （Ttk 69K）结合位点为阴性元件。此外，我们分离出一种新的转录抑制因子Rhit（热诱导转录调节因子），通过DNA亲和层析法与M-LPS启动子内的Ttk 69K结合位点结合，并证实其通过RNA干扰（RNAi）参与M-LPS的转录调节。序列分析显示，Rhit含有一个KRAB （Kruppel-associated box）结构域和一个由8个c2h2型锌指组成的dna结合域。有趣的是，暴露于热休克应激导致M-LPS表达上调，同时Rhit表达下调。此外，M-LPS的年龄依赖性表达与Rhit呈负相关。这些观察结果强烈表明，Rhit在热诱导和年龄依赖的M-LPS转录调节中起抑制作用。
Mpv17-like protein (M-LP) is a protein that has been suggested to be involved in the metabolism of reactive oxygen species. The two M-LP isoforms in mouse, M-LPS and M-LPL, are generated by the alternative usage of promoters. M-LPS is expressed exclusively in kidneys after the age of 6 weeks, whereas M-LPL is expressed ubiquitously. To elucidate the molecular basis of M-LPS expression, we searched for cis-regulatory elements in the promoter region of M-LPS and identified heat shock element half-sites as positive elements and a Tramtrack 69K (Ttk 69K) binding site as a negative element. Furthermore, we isolated a novel transcription repressor, Rhit (regulator of heat-induced transcription), that binds to the Ttk 69K binding site within the M-LPS promoter by DNA affinity chromatography and confirmed its participation in the transcriptional regulation of M-LPS by RNA interference (RNAi). Sequence analysis revealed that Rhit contains a KRAB (Kruppel-associated box) domain and a DNA-binding domain composed of eight C2H2-type zinc fingers. Interestingly, exposure to heat shock stress resulted in the upregulation of M-LPS expression concurrent with the downregulation of Rhit expression. Moreover, the age-dependent expression of M-LPS was inversely correlated with that of Rhit. These observations strongly suggest that Rhit acts as a repressor in the heat-induced and age-dependent transcriptional regulation of M-LPS.