Histone chaperones play crucial roles in maintenance of stem cell niche during plant root development
Histone chaperones play crucial roles in maintenance of stem cell niche during plant root development
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组蛋白伴侣在植物根发育过程中干细胞生态位的维持中起着至关重要的作用
DOI：
10.1111/tpj.13933
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发表时间：
2018
期刊：
影响因子：
7.2
通讯作者：
Shen Wen Hui
中科院分区：
文献类型：
--
作者：
Ma Jing;Liu Yuhao;Zhou Wangbin;Zhu Yan;Dong Aiwu;Shen Wen Hui
植物和动物界的干细胞都存在于称为干细胞龛（SCN）的特殊细胞环境中。SCN的完整性对生物体发育至关重要。在这里，我们发现H3/H4组蛋白伴侣染色质组装因子-1（CAF-1）和H2 A/H2 B组蛋白伴侣NAP 1相关蛋白1/2（NRP 1/2）在拟南芥根SCN的维持中发挥协同作用。与缺失NRP 1和NRP 2的m56 - 1双突变体或缺失CAF-1的m56 - 1 fas 2 - 4三突变体相比，m56 - 1 fas 2 - 4三突变体表现出更严重的短根表型。突变体56 - 1fas 2 - 4的根失去了正常的组织中心Quiescent Center（QC），一些原始干细胞早熟分化。微阵列分析揭示了拟南芥基因组中2735个基因（占所有基因的8%以上）在56 - 1 fas 2 - 4突变体根中的失调。一些SCN关键调控基因（如WOX 5、PLT 1、SHR）的表达没有受到限制，而植物激素生长素梯度最大值在QC时受到损害。突变体根表现出程序性细胞死亡和高水平的DNA损伤，标志着组蛋白H2A.X磷酸化（γ-H2A.X）。敲除编码DNA损伤反应激酶的共济失调-毛细血管扩张突变体（ATM）或ATR，部分挽救了56 - 1fas 2 - 4突变体的细胞死亡和短根表型。总的来说，我们的研究表明，NRP 1/2和CAF-1在调节适当的基因组转录，维持染色质复制和维持基因组完整性方面发挥协同作用，这对于连续胚后根发育期间的适当SCN功能至关重要。
Stem cells in both plant and animal kingdoms reside in a specialized cellular context called the stem cell niche (SCN). SCN integrity is crucial for organism development. Here we show that the H3/H4 histone chaperone CHROMATIN ASSEMBLY FACTOR‐1 (CAF‐1) and the H2A/H2B histone chaperone NAP1‐RELATED PROTEIN1/2 (NRP1/2) play synergistic roles in Arabidopsis root SCN maintenance. Compared with either them56‐1double mutant deprived of NRP1 and NRP2 or thefas2‐4mutant deprived of CAF‐1, the combinedm56‐1fas2‐4triple mutant displayed a much more severe short‐root phenotype. Them56‐1fas2‐4mutant root lost the normal organizing center Quiescent Center (QC), and some initial stem cells differentiated precociously. Microarray analysis unraveled the deregulation of 2735 genes within the Arabidopsis genome (representing >8% of all genes) in them56‐1fas2‐4mutant roots. Expression of some SCN key regulatory genes (e.g.WOX5,PLT1,SHR) was not limiting, rather the plant hormone auxin gradient maximum at QC was impaired. The mutant roots showed programmed cell death and high levels of the DNA damage marked histone H2A.X phosphorylation (γ‐H2A.X). Knockout of eitherATAXIA‐TELANGIECTASIA MUTATED (ATM)orATR, encoding a DNA damage response kinase, rescued in part the cell death and the short‐root phenotype of them56‐1fas2‐4mutant. Collectively, our study indicated that NRP1/2 and CAF‐1 act cooperatively in regulating proper genome transcription, in sustaining chromatin replication and in maintaining genome integrity, which are crucial for proper SCN function during continuous post‐embryonic root development.