SEQUENCING AND CHROMOSOMAL LOCALIZATION OF THE RA138 GENE ENCODING A RICE ALLERGENIC PROTEIN

A cDNA clone (RA138) encoding a rice allergenic (RA) protein has been isolated during a large-scale random sequencing of a cDNA library prep ared from developing seeds. The nucleotide sequence of the RA138 gene contained an open reading frame (ORF, 477 bp) encoding a 17 kDa protei n. The amino acid sequence deduced from the ORF was composed of 159 am ino acid residues and was highly homologous to those from RA genes pre viously isolated, such as RA5 (92% identity), RA14 (73%), and RA17 (68 %), The protein contained 10 cysteine residues that were conserved in the alpha-amylase/trypsin inhibitor family including RA proteins. Excl uding a putative signal peptide consisting of 26 amino acid residues, the mature protein would be 14.4 kDa in size and have a pi of 7.0. DNA gel blot analysis under high stringency conditions indicated that mul tiple copies of the RA138 gene were present in the rice genome. The ch romosomal location of the RA138 gene has been identified on chromosome 7 in a segregation analysis using a population of 164 recombinant inb red lines derived from a cross between Milyang 23 and Gihobyeo, The lo cus that may contain multiple copies of the RA138 was located between RFLP markers RG477A and C492 with genetic distances of 10.7 cM and 6.7 cM, respectively.