Temperature-regulated expression of a glycine-rich RNA-binding protein in the halotolerant alga Dunaliella salina.
Acclimation of the halotolerant alga Dunaliella salina to low temperature induced the accumulation of a 12.4 kDa protein (DsGRP-1) and reduction of a 13.1 kDa protein (DsGRP-2). DsGRP-1 and DsGRP-2 are boiling-stable proteins that are localised in the cytoplasm, as revealed by sub-cellular fractionation and by immuno-localisation. The proteins were partially purified and their corresponding genes were cloned. The predicted sequences are homologous to Glycine-Rich RNA-binding Proteins (GRPs) from plants and cyanobacteria. The nucleotide sequences of grp1 and grp2 differ in a short insert encoding 9 amino acids in the glycine-rich domain of DsGRP-2. grp2 contains a single intron at position 179 indicating that DsGRP-1 and DsGRP-2 are not derived from alternative splicing of a common gene. The level of grp mRNA increased at 7 degrees C and was rapidly depressed at 24 degrees C. Analysis of binding to ribonucleotide homopolymers revealed that DsGRP-1 and DsGRP-2 bind preferentially to poly-G and to poly-U indicating that they are RNA-binding proteins. It is proposed that DsGRP-1 and DsGRP-2 are encoded by distinct genes which are differentially regulated by temperature.
Zchut
Sigalit
S
Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel.
Weiss
Meira
M
Pick
Uri
U
D000222:Adaptation, Physiological / Q000187:drug effects / Q000502:physiology*; D020418:Algal Proteins / Q000235:genetics* / Q000378:metabolism; D000595:Amino Acid Sequence; D001483:Base Sequence; D000460:Chlorophyta / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D003001:Cloning, Molecular; D003080:Cold Temperature; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D005998:Glycine / Q000235:genetics*; D007150:Immunohistochemistry; D008027:Light; D013058:Mass Spectrometry; D018613:Microscopy, Confocal; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D012965:Sodium Chloride / Q000494:pharmacology*
D020418:Algal Proteins; D018076:DNA, Complementary; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D012965:Sodium Chloride; D005998:Glycine