Molecular cloning and characterization of OsUPS, a U-box containing E3 ligase gene that respond to phosphate starvation in rice (Oryza sativa).
The ubiquitin-26S proteasome system is important in the quality control of intracellular proteins. The ubiquitin-26S proteasome system includes the E1 (ubiquitin activating), E2 (ubiquitin conjugating), and E3 (ubiquitin ligase) enzymes. U-box proteins are a derived version of RING-finger domains, which have E3 enzyme activity. Here, we present the isolation of a novel U-box protein, U-box containing E3 ligase induced by phosphate starvation (OsUPS), from rice (Oryza sativa). The cDNA encoding the O. sativa U-box protein (OsUPS) comprises 1338 bp, with an open reading frame of 445 amino acids. The amino acid sequence of OsUPS cDNA shows 41-79% identity with other plant U-box homologous genes. The open reading frame of the OsUPS protein is comprised of notable domains: a single ~70-amino acid domain and a GKL domain that contains conserved glycine, lysine/arginine residues and leucine-rich feature. We found that full-length expression of OsUPS was up-regulated in both rice plants and cell culture in the absence of inorganic phosphate (P(i)). A self-ubiquitination assay indicated that the bacterially expressed OsUPS protein had E3 ligase activity, and subcellular localization results showed that OsUPS was located in the chloroplast. These results support the notion that OsUPS plays an important role in the P(i) signaling pathway through the ubiquitin-26S proteasome system.
College of Life Science and Natural Resources, Dong-A University, Busan, 604-714, Korea.
Yeon-Jae
YJ
Hur
Young Byung
YB
Yi
Jai Heon
JH
Lee
Young Soo
YS
Chung
Ho Won
HW
Jung
Dae Jin
DJ
Yun
Kyung-Min
KM
Kim
Dong Soo
DS
Park
Doh Hoon
DH
Kim
D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D001681:Biological Assay; D002736:Chloroplasts / Q000187:drug effects / Q000201:enzymology; D003001:Cloning, Molecular; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant / Q000235:genetics*; D049452:Green Fluorescent Proteins / Q000378:metabolism; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D012275:Oryza / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics*; D010710:Phosphates / Q000172:deficiency* / Q000494:pharmacology; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified; D021381:Protein Transport / Q000187:drug effects; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D013347:Subcellular Fractions / Q000187:drug effects / Q000201:enzymology; D044767:Ubiquitin-Protein Ligases / Q000235:genetics* / Q000378:metabolism; D054875:Ubiquitination / Q000187:drug effects
D010710:Phosphates; D010940:Plant Proteins; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D044767:Ubiquitin-Protein Ligases