title: Structural determinants crucial to the RNA chaperone activity of glycine-rich RNA-binding proteins 4 and 7 in Arabidopsis thaliana during the cold adaptation process.
abstract: Although glycine-rich RNA-binding proteins (GRPs) have been determined to function as RNA chaperones during the cold adaptation process, the structural features relevant to this RNA chaperone activity remain largely unknown. To uncover which structural determinants are necessary for RNA chaperone activity of GRPs, the importance of the N-terminal RNA recognition motif (RRM) and the C-terminal glycine-rich domains of two Arabidopsis thaliana GRPs (AtGRP4 harbouring no RNA chaperone activity and AtGRP7 harbouring RNA chaperone activity) was assessed via domain swapping and mutation analyses. The results of domain swapping and deletion experiments showed that the domain sequences encompassing the N-terminal RRM of GRPs were found to be crucial to the ability to complement cold-sensitive Escherichia coli mutant cells under cold stress, RNA melting ability, and freezing tolerance ability in the grp7 loss-of-function Arabidopsis mutant. In particular, the N-terminal 24 amino acid extension of AtGRP4 impedes the RNA chaperone activity. Collectively, these results reveal that domain sequences and overall folding of GRPs governed by a specific modular arrangement of RRM and glycine-rich sequences are critical to the RNA chaperone activity of GRPs during the cold adaptation process in cells.
authors.affiliation: Department of Plant Biotechnology, Chonnam National University, Gwangju, 500-757, Korea.
authors.forename: Kyung Jin
authors.initials: KJ
authors.lastname: Kwak
authors.forename: Su Jung
authors.initials: SJ
authors.lastname: Park
authors.forename: Ji Hoon
authors.initials: JH
authors.lastname: Han
authors.forename: Min Kyung
authors.initials: MK
authors.lastname: Kim
authors.forename: Seung Han
authors.initials: SH
authors.lastname: Oh
authors.forename: Yeon Soo
authors.initials: YS
authors.lastname: Han
authors.forename: Hunseung
authors.initials: H
authors.lastname: Kang
mesh_terms: D000064:Acclimatization; D017360:Arabidopsis / Q000737:chemistry / Q000235:genetics / Q000502:physiology; D029681:Arabidopsis Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D003080:Cold Temperature; D004926:Escherichia coli / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D005998:Glycine / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D018832:Molecular Chaperones / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D013329:Structure-Activity Relationship
chemical_list: D029681:Arabidopsis Proteins; D001426:Bacterial Proteins; D005998:Glycine; D018832:Molecular Chaperones; D016601:RNA-Binding Proteins; D011994:Recombinant Proteins; C118496:GRP7 protein, Arabidopsis; C506809:glycine-rich RNA-binding protein 4, Arabidopsis