title: AtCCR4a and AtCCR4b are Involved in Determining the Poly(A) Length of Granule-bound starch synthase 1 Transcript and Modulating Sucrose and Starch Metabolism in Arabidopsis thaliana.
abstract: Removing the poly(A) tail is the first and rate-limiting step of mRNA degradation and apparently an effective step not only for modulating mRNA stability but also for translation of many eukaryotic transcripts. Carbon catabolite repressor 4 (CCR4) has been identified as a major cytoplasmic deadenylase in Saccharomyces cerevisiae. The Arabidopsis thaliana homologs of the yeast CCR4, AtCCR4a and AtCCR4b, were identified by sequence-based analysis; however, their role and physiological significance in plants remain to be elucidated. In this study, we revealed that AtCCR4a and AtCCR4b are localized to cytoplasmic mRNA processing bodies, which are specific granules consisting of many enzymes involved in mRNA turnover. Double mutants of AtCCR4a and AtCCR4b exhibited tolerance to sucrose application but not to glucose. The levels of sucrose in the seedlings of the atccr4a/4b double mutants were reduced, whereas no difference was observed in glucose levels. Further, amylose levels were slightly but significantly increased in the atccr4a/4b double mutants. Consistent with this observation, we found that the transcript encoding granule-bound starch synthase 1 (GBSS1), which is responsible for amylose synthesis, is accumulated to a higher level in the atccr4a/4b double mutant plants than in the control plants. Moreover, we revealed that GBSS1 has a longer poly(A) tail in the double mutant than in the control plant, suggesting that AtCCR4a and AtCCR4b can influence the poly(A) length of transcripts related to starch metabolism. Our results collectively suggested that AtCCR4a and AtCCR4b are involved in sucrose and starch metabolism in A. thaliana.
authors: Graduate School of Life Science, Hokkaido University, Sapporo, 060-0810 Japan.
authors: Yuya
authors: Y
authors: Suzuki
authors: Graduate School of Life Science, Hokkaido University, Sapporo, 060-0810 Japan.
authors: Toshihiro
authors: T
authors: Arae
authors: Delaware Biotechnology Institute, University of Delaware, Newark, DE 19711, USA.
authors: Pamela J
authors: PJ
authors: Green
authors: Graduate School of Life Science, Hokkaido University, Sapporo, 060-0810 Japan Faculty of Science, Hokkaido University, Sapporo, 060-0810 Japan.
authors: Junji
authors: J
authors: Yamaguchi
authors: Graduate School of Life Science, Hokkaido University, Sapporo, 060-0810 Japan Faculty of Science, Hokkaido University, Sapporo, 060-0810 Japan JST PRESTO, Kawaguchi, 332-0012 Japan yukako@mail.sci.hokudai.ac.jp.
authors: Yukako
authors: Y
authors: Chiba
mesh_terms: D000688:Amylose / Q000378:metabolism; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D009154:Mutation / Q000235:genetics; D010641:Phenotype; D011061:Poly A / Q000378:metabolism*; D021381:Protein Transport / Q000187:drug effects; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D013213:Starch / Q000378:metabolism*; D013214:Starch Synthase / Q000235:genetics / Q000378:metabolism*; D013395:Sucrose / Q000378:metabolism* / Q000494:pharmacology
chemical_list: D029681:Arabidopsis Proteins; C000604709:CCR4a protein, Arabidopsis; C000604710:CCR4b protein, Arabidopsis; D012333:RNA, Messenger; D012097:Repressor Proteins; D011061:Poly A; D013395:Sucrose; D013213:Starch; D000688:Amylose; C000604711:GBSS1 protein, Arabidopsis; D013214:Starch Synthase
keywords: Arabidopsis thaliana; Carbon catabolite repressor 4; Granule-bound starch synthase 1; Poly(A) length; Sucrose and starch metabolism