title: Embryo defective12 encodes the plastid initiation factor 3 and is essential for embryogenesis in maize.
abstract: Embryo-specific mutants in maize define a unique class of genetic loci that affect embryogenesis without a significant deleterious impact on endosperm development. Here we report the characterization of an embryo specific12 (emb12) mutant in maize. Embryogenesis in the emb12 mutants is arrested at or before transition stage. The mutant embryo at an early stage exhibits abnormal cell structure with increased vacuoles and dramatically reduced internal membrane organelles. In contrast, the mutant endosperm appears normal in morphology, cell structure, starch, lipid and protein accumulation. The Emb12 locus was cloned by transposon tagging and predicts a protein with a high similarity to prokaryotic translation initiation factor 3 (IF3). EMB12-GFP fusion analysis indicates that EMB12 is localized in plastids. The RNA in situ hybridization and protein immunohistochemical analyses indicate that a high level of Emb12 expression localizes in the embryo proper at early developmental stages and in the embryo axis at later stages. Western analysis indicates that plastid protein synthesis is impaired. These results indicate that Emb12 encodes the plastid IF3 which is essential for embryogenesis but not for endosperm development in maize.
authors: State Key Lab of Agrobiotechnology, Institute of Plant Molecular Biology and Agrobiotechnology, School of Life Science, The Chinese University of Hong Kong, N.T. Hong Kong, China.
authors: Yun
authors: Y
authors: Shen
authors: Cuiling
authors: C
authors: Li
authors: Donald R
authors: DR
authors: McCarty
authors: Robert
authors: R
authors: Meeley
authors: Bao-Cai
authors: BC
authors: Tan
mesh_terms: D000595:Amino Acid Sequence; D015153:Blotting, Western; D056625:Endosperm / Q000196:embryology / Q000235:genetics / Q000648:ultrastructure; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D046529:Microscopy, Electron, Transmission; D008969:Molecular Sequence Data; D009154:Mutation; D010448:Peptide Initiation Factors / Q000235:genetics* / Q000378:metabolism; D010802:Phylogeny; D010940:Plant Proteins / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D018087:Plastids / Q000235:genetics* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012639:Seeds / Q000196:embryology / Q000235:genetics* / Q000648:ultrastructure; D017386:Sequence Homology, Amino Acid; D013997:Time Factors; D003313:Zea mays / Q000196:embryology / Q000235:genetics* / Q000378:metabolism
chemical_list: D010448:Peptide Initiation Factors; D010940:Plant Proteins