title: A Putative Chloroplast Thylakoid Metalloprotease VIRESCENT3 Regulates Chloroplast Development in Arabidopsis thaliana.
abstract: The chloroplast is the site of photosynthesis and many other essential plant metabolic processes, and chloroplast development is an integral part of plant growth and development. Mutants defective in chloroplast development can display various color phenotypes including the intriguing virescence phenotype, which shows yellow/white coloration at the leaf base and greening toward the leaf tip. Through large scale genetic screens, we identified a series of new virescent mutants including virescent3-1 (vir3-1), vir4-1, and vir5-1 in Arabidopsis thaliana. We showed that VIR3 encodes a putative chloroplast metalloprotease by map-based cloning. Through site-directed mutagenesis, we showed that the conserved histidine 235 residue in the zinc binding motif HEAGH of VIR3 is indispensable for VIR3 accumulation in the chloroplast. The chloroplast localization of VIR3 was confirmed by the transient expression of VIR3-GFP in leaf protoplasts. Furthermore, taking advantage of transgenic lines expressing VIR3-FLAG, we demonstrated that VIR3 is an intrinsic thylakoid membrane protein that mainly resides in the stromal lamellae. Moreover, topology analysis using transgenic lines expressing a dual epitope-tagged VIR3 indicated that both the N and C termini of VIR3 are located in the stroma, and the catalytic domain of VIR3 is probably facing the stroma. Blue native gel analysis indicated that VIR3 is likely present as a monomer or part of a small complex in the thylakoid membrane. This work not only implicates VIR3 as a new factor involved in early chloroplast development but also provides more insight into the roles of chloroplast proteases in chloroplast biogenesis.
authors.affiliation: From the State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest Agriculture and Forestry University, Yangling, Shaanxi 712100, People's Republic of China.
authors.forename: Yafei
authors.initials: Y
authors.lastname: Qi
authors.affiliation: From the State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest Agriculture and Forestry University, Yangling, Shaanxi 712100, People's Republic of China.
authors.forename: Xiayan
authors.initials: X
authors.lastname: Liu
authors.affiliation: From the State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest Agriculture and Forestry University, Yangling, Shaanxi 712100, People's Republic of China.
authors.forename: Shuang
authors.initials: S
authors.lastname: Liang
authors.affiliation: From the State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest Agriculture and Forestry University, Yangling, Shaanxi 712100, People's Republic of China.
authors.forename: Rui
authors.initials: R
authors.lastname: Wang
authors.affiliation: From the State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest Agriculture and Forestry University, Yangling, Shaanxi 712100, People's Republic of China.
authors.forename: Yuanfeng
authors.initials: Y
authors.lastname: Li
authors.affiliation: From the State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest Agriculture and Forestry University, Yangling, Shaanxi 712100, People's Republic of China.
authors.forename: Jun
authors.initials: J
authors.lastname: Zhao
authors.affiliation: From the State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest Agriculture and Forestry University, Yangling, Shaanxi 712100, People's Republic of China.
authors.forename: Jingxia
authors.initials: J
authors.lastname: Shao
authors.affiliation: From the State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest Agriculture and Forestry University, Yangling, Shaanxi 712100, People's Republic of China.
authors.forename: Lijun
authors.initials: L
authors.lastname: An
authors.affiliation: From the State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest Agriculture and Forestry University, Yangling, Shaanxi 712100, People's Republic of China flyfeiyu@gmail.com.
authors.forename: Fei
authors.initials: F
authors.lastname: Yu
mesh_terms: D019943:Amino Acid Substitution; D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism* / Q000648:ultrastructure; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D020134:Catalytic Domain; D002736:Chloroplasts / Q000378:metabolism* / Q000648:ultrastructure; D006639:Histidine / Q000737:chemistry / Q000378:metabolism; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D045726:Metalloproteases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D046529:Microscopy, Electron, Transmission; D009154:Mutation; D063246:Organogenesis, Plant; D010802:Phylogeny; D018515:Plant Leaves / Q000235:genetics / Q000254:growth & development / Q000378:metabolism* / Q000648:ultrastructure; D030821:Plants, Genetically Modified / Q000235:genetics / Q000254:growth & development / Q000378:metabolism / Q000648:ultrastructure; D021381:Protein Transport; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D020524:Thylakoids / Q000201:enzymology* / Q000378:metabolism / Q000648:ultrastructure; D015032:Zinc / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D008164:Luminescent Proteins; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; D006639:Histidine; D045726:Metalloproteases; C000608810:VIR3 protein, Arabidopsis; D015032:Zinc
keywords: Arabidopsis thaliana; chloroplast; membrane protein; metalloprotease; photosynthesis