title: Proteomic identification of rhythmic proteins in rice seedlings.
abstract: Many aspects of plant metabolism that are involved in plant growth and development are influenced by light-regulated diurnal rhythms as well as endogenous clock-regulated circadian rhythms. To identify the rhythmic proteins in rice, periodically grown (12h light/12h dark cycle) seedlings were harvested for three days at six-hour intervals. Continuous dark-adapted plants were also harvested for two days. Among approximately 3000 reproducible protein spots on each gel, proteomic analysis ascertained 354 spots (~12%) as light-regulated rhythmic proteins, in which 53 spots showed prolonged rhythm under continuous dark conditions. Of these 354 ascertained rhythmic protein spots, 74 diurnal spots and 10 prolonged rhythmic spots under continuous dark were identified by MALDI-TOF MS analysis. The rhythmic proteins were functionally classified into photosynthesis, central metabolism, protein synthesis, nitrogen metabolism, stress resistance, signal transduction and unknown. Comparative analysis of our proteomic data with the public microarray database (the Plant DIURNAL Project) and RT-PCR analysis of rhythmic proteins showed differences in rhythmic expression phases between mRNA and protein, suggesting that the clock-regulated proteins in rice are modulated by not only transcriptional but also post-transcriptional, translational, and/or post-translational processes.
authors.affiliation: Graduate School of Biotechnology and Plant Metabolism Research Center, Kyung Hee University, Yongin 446-701, Republic of Korea.
authors.forename: Heeyoun
authors.initials: H
authors.lastname: Hwang
authors.forename: Man-Ho
authors.initials: MH
authors.lastname: Cho
authors.forename: Bum-Soo
authors.initials: BS
authors.lastname: Hahn
authors.forename: Hyemin
authors.initials: H
authors.lastname: Lim
authors.forename: Yong-Kook
authors.initials: YK
authors.lastname: Kwon
authors.forename: Tae-Ryong
authors.initials: TR
authors.lastname: Hahn
authors.forename: Seong Hee
authors.initials: SH
authors.lastname: Bhoo
mesh_terms: D002940:Circadian Rhythm / Q000235:genetics; D003624:Darkness; D015180:Electrophoresis, Gel, Two-Dimensional; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D020411:Oligonucleotide Array Sequence Analysis; D012275:Oryza / Q000235:genetics / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D020543:Proteome / Q000235:genetics / Q000378:metabolism; D040901:Proteomics / Q000379:methods*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D036226:Seedlings / Q000235:genetics / Q000378:metabolism*
chemical_list: D010940:Plant Proteins; D020543:Proteome; D012333:RNA, Messenger