title: Arabidopsis Pumilio protein APUM5 suppresses Cucumber mosaic virus infection via direct binding of viral RNAs.
abstract: Posttranscriptional/translational regulation of gene expression is mediated by diverse RNA binding proteins and plays an important role in development and defense processes. Among the RNA-binding proteins, the mammalian Pumilio RNA-binding family (Puf) acts as posttranscriptional and translational repressors. An Arabidopsis Puf mutant, apum5-D, was isolated during a T-DNA insertional mutant screen for mutants with reduced susceptibility to Cucumber mosaic virus (CMV) infection. Interestingly, CMV RNA contained putative Pumilio-homology domain binding motifs in its 3' untranslated region (UTR) and internal places in its genome. APUM5 directly bound to the 3' UTR motifs and some internal binding motifs in CMV RNAs in vitro and in vivo. We showed that APUM5 acts as a translational repressor that regulates the 3' UTR of CMV and affects CMV replication. This study uncovered a unique defense system that Arabidopsis APUM5 specifically regulates CMV infection by the direct binding of CMV RNAs.
authors.affiliation: School of Life Sciences and Biotechnology,  Korea University, Sungbuk-gu, Seoul 136-701,  Korea.
authors.forename: Sung Un
authors.initials: SU
authors.lastname: Huh
authors.forename: Min Jung
authors.initials: MJ
authors.lastname: Kim
authors.forename: Kyung-Hee
authors.initials: KH
authors.lastname: Paek
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D015139:Blotting, Southern; D017799:Cucumovirus / Q000235:genetics / Q000378:metabolism*; D024202:Electrophoretic Mobility Shift Assay; D004797:Enzyme-Linked Immunosorbent Assay; D018506:Gene Expression Regulation, Plant / Q000235:genetics; D005966:Glucuronidase / Q000378:metabolism; D006652:Histological Techniques; D047468:Immunoprecipitation; D008969:Molecular Sequence Data; D010935:Plant Diseases / Q000276:immunology / Q000821:virology*; D012367:RNA, Viral / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA; D013045:Species Specificity
chemical_list: C578677:APUM5 protein, Arabidopsis; D029681:Arabidopsis Proteins; D012367:RNA, Viral; D016601:RNA-Binding Proteins; D012097:Repressor Proteins; D005966:Glucuronidase