ABSTRACT
This review summarizes the features of cold shock domain (CSD) proteins in the context of their interactions with nucleic acids and describes similarities and differences in the structure of cold shock proteins of prokaryotes and CSD proteins of eukaryotes with special emphasis on the functions related to the RNA/DNA-binding ability of these proteins. The mechanisms and specificity of their interaction with nucleic acids in relation to the growing complexity of protein domain structure are described, as well as various complexes of the mammalian Y-box binding protein 1 (YB-1) with nucleic acids (filaments, globules, toroids). The role of particular amino acid residues in the binding of nitrogenous bases and the sugar-phosphate backbone of nucleic acids is emphasized. The data on the nucleic acid sequences recognized by the Y-box binding proteins are systematized. Post-translational modifications of YB-1, especially its phosphorylation, affect the recognition of specific sequences in the promoter regions of various groups of genes by YB-1 protein. The data on the interaction of Lin28 protein with let-7 miRNAs are summarized. The features of the domain structure of plant CSD proteins and their effect on the interaction with nucleic acids are discussed.
Subject(s)
Cold Shock Proteins and Peptides/chemistry , Cold Shock Proteins and Peptides/metabolism , Nucleic Acids/metabolism , Protein Domains , Protein Processing, Post-Translational , Y-Box-Binding Protein 1/metabolism , Amino Acid Sequence , Animals , Bacterial Proteins/chemistry , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , Cold Shock Proteins and Peptides/genetics , Cold Temperature , Gene Expression Regulation , Humans , Plant Proteins/chemistry , Plant Proteins/genetics , Plant Proteins/metabolism , RNA-Binding Proteins/chemistry , RNA-Binding Proteins/genetics , RNA-Binding Proteins/metabolism , Y-Box-Binding Protein 1/chemistryABSTRACT
Plant cold shock domain proteins (CSDPs) are DNA/RNA-binding proteins. CSDPs contain the conserved cold shock domain (CSD) in the N-terminal part and a varying number of the CCHC-type zinc finger (ZnF) motifs alternating with glycine-rich regions in the C-terminus. CSDPs exhibit RNA chaperone and RNA-melting activities due to their nonspecific interaction with RNA. At the same time, there are reasons to believe that CSDPs also interact with specific RNA targets. In the present study, we used three recombinant CSDPs from the saltwater cress plant (Eutrema salsugineum) - EsCSDP1, EsCSDP2, EsCSDP3 with 6, 2, and 7 ZnF motifs, respectively, and showed that their nonspecific interaction with RNA is determined by their C-terminal fragments. All three proteins exhibited high affinity to the single-stranded regions over four nucleotides long within RNA oligonucleotides. The presence of guanine in the single- or double-stranded regions was crucial for the interaction with CSDPs. Complementation test using E. coli BX04 cells lacking four cold shock protein genes (ΔcspA, ΔcspB, ΔcspE, ΔcspG) revealed that the specific binding of plant CSDPs with RNA is determined by CSD.
