47. cDNA sequence of a novel rice serine/threonine protein kinase

Masao hamada, Kimiko yamamoto, Takuji sasaki and Toshihiko hino

1) Masters Program in Biosystem Studies, Tsukuba University, Tennoudai 1-1-1, Tsukuba, 305 Japan.

2) Rice Genome Research Program, Society for Techno-innovation of Agriculture, Forestry and Fisheries, 446-1 Ippaizuka, Kamiyokoba, Tsukuba, 305 Japan.

3) Rice Genome Research Program, National Institute of Agrobiological Resources, Kannondai 2-1-2, Tsukuba, 305 Japan.

 Serine/threonine kinases have been shown to play important roles in many cellular functions. We determined the cDNA sequence corresponding to and the map position of a new rice serine/threonine kinase gene. This cDNA clone, S11344, was selected from a cDNA library prepared from a green shoot of rice (Nipponbare, a japonica variety), during large-scale cDNA sequencing in Rice Genome Research Program.

The method of cDNA cloning was the same as that used for a rice callus cDNA library (Sasaki et al. 1994). The insert of S 11344 was excised, sonicated, and subcloned into the plasmid pBluescriptII SK+ and then sequenced by the dideoxy method. Using Inherit Assembler software (Perkin Elmer, Applied Biosystems, USA), we determined the full sequence of S11 344 (Fig. 1).

S11344 is a 1960 bp, full-length cDNA including a 1602 bp open reading frame. The protein predicted from this cDNA is 534 amino acids long, and contains the putative catalytic domain of protein kinase. Similarity analyses based on both the amino acid sequence (against Swiss-Prot, PIR, Genpept and PDB) and the nucleotide sequence (against DDBJ, EMBL and GenBank) revealed striking homology with the human STK2 gene, which corresponds to a cfc2-like kinase (Levedakou et al. 1995). The amino acid sequences of the kinase domains of S11344 and STK2 were 31.1% identical, and 78.9% of these regions were composed of similar amino acid residues (data not shown). The conserved DLKPEN motif of serine/threonine kinases was present in the predicted S11 344 protein as DLKCSN.

Southern hybridizations of rice genomic DNA (from Nipponbare and Kasalath) were performed using S11344 as a probe with the ECL labeling and detection system (Amersham, UK). The position of S11344 on a high density restriction fragment length polymorphism (RFLP) linkage map with approximately 1,000 markers (Kurata et al. 1994) was determined with MAPMAKER. To detect only the S11344 gene, the 3'

Research Notes 155
Fig. 1. The nucleotide and deduced amino acid sequences corresponding to S11344. The DLKPEN motif, present in S11344 as DLKCSN, is enclosed by a rectangle. 156 Rice Genetics Newsletter Vol. 13 Chromosome 2 Fig. 2. Location of S11344 on the RFLP linkage map. The position of S11344 is indicated by the arrow.
Research Notes 157
untranslated region (UTR) sequence probe was used. This hybridization was considered to give a clone-specific signal, since 3' UTR was expected to have a gene specific sequence. Apa I - digested DNA showed polymorphism with both cultivars (12 kb with Nipponbare and 15 kb with Kasalath, data not shown). S11344 was mapped on the 67 cM locus on chromosome 2 (Fig. 2).

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