title: CpLEPA is critical for chloroplast protein synthesis under suboptimal conditions in Arabidopsis thaliana.
abstract: LEPA is one of the most conserved translation factors and is found from bacteria to higher plants. However, the physiological function of the chloroplast LEPA homolog in higher plants remains unknown. Herein, we demonstrate the physiological role of cpLEPA in enabling efficient photosynthesis in higher plants. The cplepa-1 mutant displays slightly high chlorophyll fluorescence and pale green phenotypes under normal growth conditions. The growth of the cplepa-1 mutant is reduced when grown on soil, and greater reduction is observed under intense light illumination. Photosynthetic activity is impaired in the cplepa-1 mutants, which is reflected in the decreased steady-state levels of chloroplast proteins. In vivo protein labeling experiments explained the decrease in the steady-state levels of chloroplast proteins. An abnormal association of the chloroplast-encoded mRNAs with ribosomes suggests that the protein synthesis deficiencies in cplepa-1 are due to defects in translation initiation in the chloroplasts. The cpLEPA protein appears to be an essential translation factor that promotes the efficiency of chloroplast protein synthesis.
authors.affiliation: Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, China.
authors.forename: Dai-Li
authors.initials: DL
authors.lastname: Ji
authors.forename: Hong
authors.initials: H
authors.lastname: Lin
authors.forename: Wei
authors.initials: W
authors.lastname: Chi
authors.forename: Li-Xin
authors.initials: LX
authors.lastname: Zhang
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D002736:Chloroplasts / Q000235:genetics* / Q000378:metabolism*; D017124:Conserved Sequence; D039642:Eukaryotic Initiation Factors / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D055786:Gene Knockout Techniques; D023061:Gene Order; D008969:Molecular Sequence Data; D009154:Mutation; D020653:Peptide Elongation Factor G / Q000737:chemistry; D010641:Phenotype; D014176:Protein Biosynthesis; D021381:Protein Transport; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012270:Ribosomes; D016415:Sequence Alignment; D020524:Thylakoids / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D039642:Eukaryotic Initiation Factors; D020653:Peptide Elongation Factor G; D012333:RNA, Messenger; C581745:cpLEPA protein, Arabidopsis