title: Posttranscriptional control of photosynthetic mRNA decay under stress conditions requires 3' and 5' untranslated regions and correlates with differential polysome association in rice.
abstract: Abiotic stress, including drought, salinity, and temperature extremes, regulates gene expression at the transcriptional and posttranscriptional levels. Expression profiling of total messenger RNAs (mRNAs) from rice (Oryza sativa) leaves grown under stress conditions revealed that the transcript levels of photosynthetic genes are reduced more rapidly than others, a phenomenon referred to as stress-induced mRNA decay (SMD). By comparing RNA polymerase II engagement with the steady-state mRNA level, we show here that SMD is a posttranscriptional event. The SMD of photosynthetic genes was further verified by measuring the half-lives of the small subunit of Rubisco (RbcS1) and Chlorophyll a/b-Binding Protein1 (Cab1) mRNAs during stress conditions in the presence of the transcription inhibitor cordycepin. To discern any correlation between SMD and the process of translation, changes in total and polysome-associated mRNA levels after stress were measured. Total and polysome-associated mRNA levels of two photosynthetic (RbcS1 and Cab1) and two stress-inducible (Dehydration Stress-Inducible Protein1 and Salt-Induced Protein) genes were found to be markedly similar. This demonstrated the importance of polysome association for transcript stability under stress conditions. Microarray experiments performed on total and polysomal mRNAs indicate that approximately half of all mRNAs that undergo SMD remain polysome associated during stress treatments. To delineate the functional determinant(s) of mRNAs responsible for SMD, the RbcS1 and Cab1 transcripts were dissected into several components. The expressions of different combinations of the mRNA components were analyzed under stress conditions, revealing that both 3' and 5' untranslated regions are necessary for SMD. Our results, therefore, suggest that the posttranscriptional control of photosynthetic mRNA decay under stress conditions requires both 3' and 5' untranslated regions and correlates with differential polysome association.
authors.affiliation: School of Biotechnology and Environmental Engineering, Myongji University, Yongin 449-728, Korea.
authors.forename: Su-Hyun
authors.initials: SH
authors.lastname: Park
authors.forename: Pil Joong
authors.initials: PJ
authors.lastname: Chung
authors.forename: Piyada
authors.initials: P
authors.lastname: Juntawong
authors.forename: Julia
authors.initials: J
authors.lastname: Bailey-Serres
authors.forename: Youn Shic
authors.initials: YS
authors.lastname: Kim
authors.forename: Harin
authors.initials: H
authors.lastname: Jung
authors.forename: Seung Woon
authors.initials: SW
authors.lastname: Bang
authors.forename: Yeon-Ki
authors.initials: YK
authors.lastname: Kim
authors.forename: Yang
authors.initials: Y
authors.lastname: Do Choi
authors.forename: Ju-Kon
authors.initials: JK
authors.lastname: Kim
mesh_terms: D020413:3' Untranslated Regions / Q000235:genetics; D020121:5' Untranslated Regions / Q000235:genetics; D016000:Cluster Analysis; D003080:Cold Temperature; D055864:Droughts; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant / Q000235:genetics; D006207:Half-Life; D020411:Oligonucleotide Array Sequence Analysis; D012275:Oryza / Q000187:drug effects / Q000235:genetics*; D010788:Photosynthesis / Q000187:drug effects / Q000235:genetics*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D011132:Polyribosomes / Q000187:drug effects / Q000378:metabolism*; D020871:RNA Stability / Q000187:drug effects / Q000235:genetics*; D012965:Sodium Chloride / Q000494:pharmacology; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics*; D014158:Transcription, Genetic / Q000187:drug effects; D020506:Untranslated Regions / Q000235:genetics*
chemical_list: D020413:3' Untranslated Regions; D020121:5' Untranslated Regions; D010940:Plant Proteins; D020506:Untranslated Regions; D012965:Sodium Chloride