title: Proteomic analysis of embryonic proteins synthesized from long-lived mRNAs during germination of rice seeds.
abstract: Dry seeds contain translatable, long-lived mRNAs that are stored during seed maturation. Early studies using transcriptional inhibitors supported the view that protein synthesis during the initial phase of germination occurs on long-lived mRNA templates. Rice seeds were treated with the transcriptional inhibitor actinomycin D (Act D), and the embryonic proteins translated from long-lived mRNAs during germination were identified using a proteomic analysis. De novo transcription was not required for germination of rice seeds, since >80% of seeds germinated when transcription was prevented by treatment with Act D. In contrast, germination was completely inhibited in the presence of cycloheximide, an inhibitor of translation. Thus, de novo protein synthesis is necessary for germination of rice seeds. The proteomic analysis revealed that 20 proteins are up-regulated during germination, even after Act D treatment. Many of the up-regulated proteins are involved in carbohydrate metabolism and cytoskeleton formation. These results indicate that some of the germination-specific proteins involved in energy production and maintenance of cell structure in rice seeds are synthesized from long-lived mRNAs. The timing of translation of eight up-regulated proteins was clearly later than that of the other up-regulated proteins under conditions in which transcription was inhibited by Act D, suggesting that translation of long-lived mRNAs in rice seeds is regulated according to the germination phase.
authors.affiliation: Department of Plant Production, United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, Japan.
authors.forename: Naoto
authors.initials: N
authors.lastname: Sano
authors.forename: Hadian
authors.initials: H
authors.lastname: Permana
authors.forename: Ryota
authors.initials: R
authors.lastname: Kumada
authors.forename: Yoshihito
authors.initials: Y
authors.lastname: Shinozaki
authors.forename: Takanari
authors.initials: T
authors.lastname: Tanabata
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Yamada
authors.forename: Tadashi
authors.initials: T
authors.lastname: Hirasawa
authors.forename: Motoki
authors.initials: M
authors.lastname: Kanekatsu
mesh_terms: D003517:Cyclopentanes / Q000494:pharmacology; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D018525:Germination / Q000235:genetics / Q000502:physiology; D012275:Oryza / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism* / Q000502:physiology; D054883:Oxylipins / Q000494:pharmacology; D040901:Proteomics / Q000379:methods*; D012639:Seeds / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism* / Q000502:physiology
chemical_list: D003517:Cyclopentanes; D054883:Oxylipins; C011006:jasmonic acid