The Histone Chaperone NRP1 Interacts With WEREWOLF to Activate GLABRA2 in Arabidopsis Root Hair Development
The Histone Chaperone NRP1 Interacts With WEREWOLF to Activate GLABRA2 in Arabidopsis Root Hair Development
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组蛋白伴侣 NRP1 与 WEREWOLF 相互作用激活拟南芥根毛发育中的 GLABRA2
DOI：
10.1105/tpc.16.00719
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
Aiwu Dong
中科院分区：
文献类型：
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作者：
Yan Zhu;Liang Rong;Qiang Luo;Baihui Wang;Nana Zhou;Yue Yang;Chi Zhang;Haiyang Feng;Lina Zheng;Wen-Hui Shen;Jinbiao Ma;Aiwu Dong
核小体组装蛋白1(NAP1)定义了一个进化上保守的组蛋白伴侣蛋白家族，NAP1家族基因NAP1相关蛋白1(Nrp1)和NRP2的功能丧失会导致异常的根毛形成。然而，潜在的分子机制仍不清楚。在这里，我们证明了Nrp1在体外和体内与转录因子狼人(WER)相互作用，并以WER依赖的方式在GLABRA2(GL2)启动子上富含。结晶学分析表明，Nrp1通过其N-端α-螺旋形成二聚体。Nrp1的突变体要么破坏α-螺旋二聚反应，要么移除C末端的酸性尾巴，破坏其与组蛋白和Wer的结合，从而导致未能激活GL2转录并挽救突变表型。我们的结果进一步证明，依赖于WER的Nrp1在GL2启动子上的浓缩参与了体内局部组蛋白的清除和核小体的丢失。生化竞争分析表明，Nrp1与组蛋白之间的结合可能抵消了组蛋白对WER-DNA相互作用的抑制作用。总之，我们的研究对组蛋白伴侣通过与基因特异的转录因子相互作用来调节染色质结构以促进根毛正常发育的分子机制提供了重要的见解。
NUCLEOSOME ASSEMBLY PROTEIN1 (NAP1) defines an evolutionarily conserved family of histone chaperones and loss of function of theArabidopsis thalianaNAP1 family genesNAP1-RELATED PROTEIN1(NRP1) andNRP2causes abnormal root hair formation. Yet, the underlying molecular mechanisms remain unclear. Here, we show that NRP1 interacts with the transcription factor WEREWOLF (WER) in vitro and in vivo and enriches at theGLABRA2(GL2) promoter in a WER-dependent manner. Crystallographic analysis indicates that NRP1 forms a dimer via its N-terminal α-helix. Mutants of NRP1 that either disrupt the α-helix dimerization or remove the C-terminal acidic tail, impair its binding to histones and WER and concomitantly lead to failure to activateGL2transcription and to rescue thenrp1-1 nrp2-1mutant phenotype. Our results further demonstrate that WER-dependent enrichment of NRP1 at theGL2promoter is involved in local histone eviction and nucleosome loss in vivo. Biochemical competition assays imply that the association between NRP1 and histones may counteract the inhibitory effect of histones on the WER-DNA interaction. Collectively, our study provides important insight into the molecular mechanisms by which histone chaperones are recruited to target chromatin via interaction with a gene-specific transcription factor to moderate chromatin structure for proper root hair development.