Abstract: A cytoplasmic serine􊄯thronine protein kinase gene (OsSTK), had been cloned from Oryza genus. It was found high conservative and constitutive expression in Oryza. OsSTK gene had two exons, separated by 114 bp short intron. The open reading frame of OsSTK gene that predicted encoded a 419 amino acids protein . The amino acid sequence of OsSTK had low identities ( less than 53% ) with any other known protein kinase . The phylogenetic tree based on the partial DNA sequences of OsSTK from different species and types of wild rice and cultivated rice, was close to the taxation system of
rice . Interestingly , OsSTK had a serine, including basic amino acids and charged amino acids abundant polypeptide with a “GDGDGDGDG”sequence at N- terminal that had not been found in any other genes. OsSTK may play dual specificity that phosphorylates both serine􊄯thronine and tyrosone, because the amino acids module of VIb , VIII and XI catalytic domain have both the serine􊄯thronine and tyrosine kinase characters .

Key words: Oryza