title: The tomato DDI2, a PCNA ortholog, associating with DDB1-CUL4 complex is required for UV-damaged DNA repair and plant tolerance to UV stress.
abstract: CULLIN 4 (CUL4)-DAMAGED DNA binding protein 1 (DDB1)-based ubiquitin E3 ligase modulates diverse cellular processes including repair of damaged genomic DNA. In this study, an uncharacterized gene termed as DDB1-Interacting protein 2 (DDI2) was identified in yeast two-hybrid screening with bait gene DDB1. The co-immunoprecipitation (co-IP) assays further demonstrated that DDI2 is associated with tomato DDB1-CUL4 complex in vivo. It appears that DDI2 encodes an ortholog of proliferating cell nuclear antigen (PCNA). Confocal microscope observation indicated that DDI2-GFP fusion protein was localized in nuclei. The expression of DDI2 gene is constitutive but substantially enhanced by UV-C irradiation. The transgenic tomato plants with overexpression or knockdown of DDI2 gene displayed the increased or decreased tolerance, respectively, to UV-C stress and chemical mutagen cisplatin. The quantitative analysis of UV-induced DNA lesions indicated that the dark repair of DNA damage was accelerated in DDI2 overexpression lines but delayed in knockdown lines. Conclusively, tomato DDI2 gene is required for UV-induced DNA damage repair and plant tolerance to UV stress. In addition, fruits of DDI2 transgenic plants are indistinguishable from that of wild type, regarding fresh weight and nutrient quality. Therefore, overexpression of DDI2 offers a suitable strategy for genetic manipulation of enhancing plant tolerance to UV stress.
authors.affiliation: Ministry of Education Key Laboratory for Bio-resource and Eco-environment, College of Life Science, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610064, China.
authors.forename: Lanyang
authors.initials: L
authors.lastname: Gao
authors.affiliation: Ministry of Education Key Laboratory for Bio-resource and Eco-environment, College of Life Science, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610064, China.
authors.forename: Shuzhang
authors.initials: S
authors.lastname: Yang
authors.affiliation: School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei 230009, China.
authors.forename: Yunye
authors.initials: Y
authors.lastname: Zhu
authors.affiliation: Ministry of Education Key Laboratory for Bio-resource and Eco-environment, College of Life Science, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610064, China.
authors.forename: Junfang
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Institute of Flower, Sichuan Academy of Botanical Engineering, Zizhong 641200, China.
authors.forename: Ming
authors.initials: M
authors.lastname: Zhuo
authors.affiliation: School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei 230009, China.
authors.forename: Ming
authors.initials: M
authors.lastname: Miao
authors.affiliation: School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei 230009, China.
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Tang
authors.affiliation: Ministry of Education Key Laboratory for Bio-resource and Eco-environment, College of Life Science, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610064, China; School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei 230009, China. Electronic address: llyysshh1122@163.com.
authors.forename: Yongsheng
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China. Electronic address: wangsh1@cib.ac.cn.
authors.forename: Songhu
authors.initials: S
authors.lastname: Wang
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics*; D002467:Cell Nucleus; D044842:Cullin Proteins / Q000378:metabolism; D004249:DNA Damage; D004260:DNA Repair / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D005638:Fruit; D017343:Genes, Plant; D018551:Solanum lycopersicum / Q000235:genetics* / Q000378:metabolism; D009687:Nuclear Proteins / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D018809:Proliferating Cell Nuclear Antigen / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D013312:Stress, Physiological / Q000235:genetics; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism; D014466:Ultraviolet Rays
chemical_list: D044842:Cullin Proteins; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D010940:Plant Proteins; D018809:Proliferating Cell Nuclear Antigen; D044767:Ubiquitin-Protein Ligases
keywords: CRL4 ubiquitin E3 ligase; DDI2; DNA damage repair; PCNA; Tomato (Solanum lycopersicum); UV stress