Novel gene encoding a Ca2+-binding protein and under hexokinase-dependent sugar regulation.
A cDNA encoding a predicted 15-kDa protein was earlier isolated from sugar-induced genes in rice embryos (Oryza sativa L.) by cDNA microarray analysis. Here we report that this cDNA encodes a novel Ca2+-binding protein, named OsSUR1 (for Oryza sativa sugar-up-regulated-1). The recombinant OsSUR1 protein expressed in Escherichia coli had 45Ca2+-binding activity. Northern analysis showed that the OsSUR1 gene was expressed mainly in the internodes of mature plants and in embryos at an early stage of germination. Expression of the OsSUR1 gene was induced by sugars that could serve as substrates of hexokinase, but expression was not repressed by Ca2+ signaling inhibitors, calmodulin antagonists and inhibitors of protein kinase or protein phosphatase. These results suggested that Os-SUR1 gene expression was stimulated by a hexokinase-dependent pathway not mediated by Ca2+.
Otsuki
Shigeo
S
Division of Biological Sciences, Graduate School of Science, Hokkaido University, Kita-ku N10-W8, Sapporo 060-0810, Japan.
Ikeda
Akira
A
Sunako
Tomomi
T
Muto
Shoshi
S
Yazaki
Junshi
J
Nakamura
Keiko
K
Fujii
Fumiko
F
Shimbo
Kanako
K
Otsuka
Yoshimi
Y
Yamamoto
Kimiko
K
Sakata
Katsumi
K
Sasaki
Takuji
T
Kishimoto
Naoki
N
Kikuchi
Shoshi
S
Yamaguchi
Junji
J
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D002118:Calcium / Q000737:chemistry / Q000378:metabolism; D002127:Calcium Isotopes; D002135:Calcium-Binding Proteins / Q000235:genetics* / Q000378:metabolism*; D050260:Carbohydrate Metabolism; D002241:Carbohydrates / Q000494:pharmacology; D018076:DNA, Complementary / Q000235:genetics* / Q000302:isolation & purification; D018744:DNA, Plant / Q000235:genetics* / Q000302:isolation & purification; D004926:Escherichia coli / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000235:genetics / Q000502:physiology; D006593:Hexokinase / Q000378:metabolism*; D008969:Molecular Sequence Data; D012275:Oryza / Q000196:embryology / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction
D002127:Calcium Isotopes; D002135:Calcium-Binding Proteins; D002241:Carbohydrates; D018076:DNA, Complementary; D018744:DNA, Plant; D010940:Plant Proteins; D011994:Recombinant Proteins; D006593:Hexokinase; D002118:Calcium