| Summary: | 碩士 === 國立中興大學 === 分子生物學研究所 === 86 ===
A receptor-like protein kinase gene, Ose711, has been cloned from rice (Oryza sativa) embryo. The cDNA Ose711is 2,195 bp in length, consisting of a 245 bp 5' untranslated region, an open reading frame of 1,707 bp, and a 243 bp 3' untranslated region. The deduced translation product consist of 568 amino acids. There are eight introns in the genomic DNA of Ose711. The promoter region has a predicted TATA box and two CAAT boxes locating at 314,361and 390 nucleotides from the upstream of the transcription site. There are many repeated sequences in the promoter region. The predicted Ose711 protein includes a transmembrane domain, a catalytic domain and an extracellular domain. The catalytic domain consists of all 11 conserved subdomains of eukaryotic protein kinases and all invariant amino acid residues at their proper positions.
The catalytic domain of Ose711 gene was cloned and expressed in Escherichia coli. The results show that the expressed protein is capable of autophosphorylation using ATP as the phosphate donor. Ose711 appears to fall into the serine/threonine class of protein kinases, because it contains diagnostic sequences of this family (subdomain VIb and VIII). Southern blot analysis indicated that Ose711is a single copy gene in rice genome. The Ose711 gene was temporally expressed during embryo development, with the mRNA level being most abundant in early embryos which was gradually decreased till its maturation. The Ose711 mRNA was not detectable in the mature embryo but was observed in 10-DAP's de-embryo grains, coleoptile and young leaves.
Another gene studied is Ose716. The Ose716 cDNA is 675 bp in length with an open reading frame of 249 bp and a 414 bp 3'untranslated region. The deduced translation product consists of 83 amino acid residues including an N-terminal signal peptide. Computer analysis by using GenomoNet revealed that this protein has a tendency to be targeted to the vacuole. The size of its transcript is about 0.8 kb. The mRNA of Ose716 was highly expressed in rice embryo and coleoptile, but not in the mature embryo and other tissues. These results suggest that Ose716 is an embryo specific gene during embryogenesis.
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