Molecular characterization of a novel salt-inducible gene for an OSBP (oxysterol-binding protein)-homologue from soybean.
Oxysterol-binding protein (OSBP) and its homologues constitute a protein family in many eukaryotes from yeast to humans, which are involved in cellular lipid metabolism, vesicle transport and signal transduction. In this study, we characterized a novel salt-inducible gene for an OSBP-homologue from soybean (Glycine max [L.] Merr.). The soybean OSBP-homologous gene, denoted as G. max OSBP (GmOSBP), encoded a 789 aa putative protein with two characteristic domains; the pleckstrin homology (PH) domain and the ligand-binding (LB) domain, in the N- and C-terminus, respectively. The GmOSBP-PH domain showed localization into/around the nucleus in a transient subcellular localization assay. The phylogenetic relationship of the GmOSBP-LB domain to those in other OSBP-homologues suggested that GmOSBP might bind a lipid molecule(s) different from the ligand-candidates found for the human/yeast OSBP-homologues. The GmOSBP gene was constitutively transcribed in all of the soybean organs examined--root, stem and trifoliate leaf--at low levels and was highly induced in all these organs by high-salt stress (300 mM NaCl). Interestingly, gene expression of GmOSBP was also markedly induced in the senesced soybean cotyledon, which contains high levels of a variety of cellular lipids utilized for energy for germination and as membrane components. Therefore, we suggest that GmOSBP may be involved in some physiological reactions for stress-response and cotyledon senescence in the soybean.
Li
Dong Yan
DY
Laboratory of Biochemistry and Molecular Biology, Department of Applied Biological Resource Sciences, School of Agriculture, Ibaraki University, Chuo 3-21-1, Ami-machi, Inashiki-gun, Ibaraki, Japan.
Inoue
Hayami
H
Takahashi
Masayuki
M
Kojima
Toshio
T
Shiraiwa
Masakazu
M
Takahara
Hidenari
H
D000595:Amino Acid Sequence; D002467:Cell Nucleus / Q000737:chemistry; D016922:Cellular Senescence / Q000235:genetics; D018548:Cotyledon / Q000235:genetics / Q000502:physiology; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000502:physiology*; D008969:Molecular Sequence Data; D010802:Phylogeny; D010940:Plant Proteins / Q000032:analysis / Q000235:genetics* / Q000378:metabolism; D017434:Protein Structure, Tertiary; D011987:Receptors, Steroid / Q000032:analysis / Q000235:genetics* / Q000378:metabolism; D012965:Sodium Chloride / Q000378:metabolism / Q000494:pharmacology; D013025:Glycine max / Q000187:drug effects / Q000235:genetics*; D000098825:Oxysterol Binding Proteins
D010940:Plant Proteins; D011987:Receptors, Steroid; D000098825:Oxysterol Binding Proteins; D012965:Sodium Chloride