Functional characterization of rice CW-domain containing zinc finger proteins involved in histone recognition

• Published in: Plant science (Limerick) 2017-10, Vol.263, p.168-176
• Main Authors: Zhang, Zhe, Zhang, Feng, Cheng, Zhi-jun, Liu, Ling-long, Lin, Qi-bing, Wu, Fu-qing, Zhang, Huan, Wang, Jiu-lin, Wang, Jie, Guo, Xiu-ping, Zhang, Xin, Lei, Cai-lin, Zhao, Zhi-chao, Zhu, Shan-shan, Wan, Jian-min
• Format: Article
• Language: English
• Subjects: Amino Acid Motifs; CW domain; DNA Methylation; Gene Expression Regulation, Plant; Histone Code; Histone methylation; Histone recognition; Histones - genetics; Oryza - genetics; Oryza - metabolism; Oryza sativa; Phylogeny; Plant Proteins - genetics; Plant Proteins - metabolism; Sequence Alignment; Zinc finger; Zinc Fingers - genetics
• ISSN: 0168-9452; 1873-2259
• DOI: 10.1016/j.plantsci.2017.06.013

•Three cysteine-tryptophan (CW) −domain containing zinc finger (ZF) proteins involved in histone recognition were identified from rice genome, viz. OsCW-ZF3, OsCW-ZF5 and OsCW-ZF7.•OsCW-ZFs have binding affinity to histone H3K4 with different methylation.•OsCW-ZF7 can interact with TAFII20, a transcription initiation factor TFIID 20kDa subunit.•OsCW-ZF7 mutant has awn developmental defects. Histone recognition is important for understanding the mechanisms of histone modification, which play a pivotal role in transcriptional regulation during plant development. Here, we identified three cysteine-tryptophan (CW)-domain containing zinc finger (ZF) proteins involved in histone recognition, namely OsCW-ZF3, OsCW-ZF5 and OsCW-ZF7. Protein sequence analysis showed that they have two unknown motifs in addition to the CW domain. All three OsCW-ZFs were expressed in aerial tissues, with relatively high levels in developing panicles. Subcellular localization revealed that the OsCW-ZFs target the cell nucleus and CW domains are not necessary for their nuclear localization. In contrast to OsCW-ZF3 and OsCW-ZF5 where the CW domains bind histone H3 lysine 4 with different methylated forms (H3K4me), the CW domain from OsCW-ZF7 recognizes only trimethylated histone H3 lysine 4 (H3K4me3). Analysis of mutant suggested that three conserved tryptophan residues in the CW domain are essential for binding to H3K4me. Further study found that OsCW-ZF7 interacts with TAFII20, a transcription initiation factor TFIID 20kDa subunit. Knockout of OsCW-ZF7 caused defective development of awns. This study provides new insights into our understanding of the CW domain and lays a foundation for further investigation of its roles in rice.