Comparative analysis of Arabidopsis zinc finger-containing glycine-rich RNA-binding proteins during cold adaptation.
Among the three zinc finger-containing glycine-rich RNA-binding proteins, named AtRZ-1a, AtRZ-1b, and AtRZ-1c, in the Arabidopsis thaliana genome, AtRZ-1a has previously been shown to enhance cold and freezing tolerance in Arabidopsis. Here, we determined and compared the functional roles of AtRZ-1b and AtRZ-1c in Arabidopsis and Escherichia coli under cold stress conditions. AtRZ-1b, but not AtRZ-1c, successfully complemented the cold sensitivity of E. coli BX04 mutant cells lacking four cold shock proteins. Domain deletion and site-directed mutagenesis showed that the zinc finger motif of AtRZ-1b is important for its complementation ability, and that the truncated N- and C-terminal domains of AtRZ-1b and AtRZ-1c harbor the complementation ability. Despite an increase in transcript levels of AtRZ-1b and AtRZ-1c under cold stress, overexpression or loss-of-function mutations did not affect seed germination or seedling growth of Arabidopsis under cold stress conditions. AtRZ-1b and AtRZ-1c proteins, being localized to the nucleus, have been shown to bind non-specifically to RNA sequences in vitro, in comparison to AtRZ-1a that is localized to both the nucleus and the cytoplasm and binds preferentially to G- or U-rich RNA sequences. Taken together, these results demonstrate that the three AtRZ-1 family members showing different cellular localization and characteristic nucleic acid-binding property have a potential to contribute differently to the enhancement of cold tolerance in Arabidopsis and E. coli.
Kim
Won Yong
WY
Department of Plant Biotechnology, Agricultural Plant Stress Research Center and Biotechnology Research Institute, College of Agriculture and Life Sciences, Chonnam National University, Gwangju 500-757, Republic of Korea.
Kim
Joo Yeol
JY
Jung
Hyun Ju
HJ
Oh
Seung Han
SH
Han
Yeon Soo
YS
Kang
Hunseung
H
D000222:Adaptation, Physiological / Q000235:genetics; D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D002467:Cell Nucleus / Q000378:metabolism; D057773:Cold Shock Proteins and Peptides / Q000235:genetics / Q000378:metabolism; D003080:Cold Temperature; D003593:Cytoplasm / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D017343:Genes, Plant; D016296:Mutagenesis; D009154:Mutation; D009711:Nucleotides / Q000378:metabolism; D012313:RNA / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D036226:Seedlings / Q000254:growth & development; D012639:Seeds / Q000254:growth & development; D013312:Stress, Physiological / Q000235:genetics; D016335:Zinc Fingers / Q000235:genetics*
D029681:Arabidopsis Proteins; D057773:Cold Shock Proteins and Peptides; D009711:Nucleotides; D016601:RNA-Binding Proteins; D012313:RNA