Up to date, about ten glutelin cDNA or genomic clones have been reported (Kusaba et al. 2003, Masumura et al. 1989, Okita et al. 1989, Takaiwa and Oono 1991). The genes controlling glutelin polypeptides were located on chromosome 1, 2, 3 and 10 (Iida et al. 1997, Qu et al. 2002, Uemura et al. 1996, 2003). Two-dementional electrophoretic (IEF/SDS-PAGE) analysis indicated that each of the glutelin IEF bands corresponds to one individual spot in SDS-PAGE (Uemura et al., 1996). However, the interrelationships between the IEF glutelin polypeptide bands and the genomic/cDNA sequences have not been known, with a exception of glu4 gene which controlled a glutelin polypeptide consisting of pI 6.71 or pI 8.74 bands was identical to GluA-1 gene (Qu. et al. 2002)

Glu6 gene controlling a glutelin polypeptide (M.M. 38kD) with pI6.55 consisting Alpha-2 in Kinmaze (a japonica rice variety) or pI6.52 in Kasalath (an indica rice variety) was located on chromosome 3 (Uemura et al. 2003). Homology search for the nucleotide sequence of chromosome 3 revealed that the sequence in the BAC clone OSJNBa0083F15 was homologous to that of the glutelin cDNA clone for GluA-3. The results of the sequence for GluA-3 showed that T-245, G-976 and T-1047 in Kinmaze substituted to G, A and C in Kasalath, respectively. The nucleotides substitution resulted in amino acid substitution for Phe-76, Arg-262 and Ser-286 residues in Kinmaze to Ser, His and Pro residues in Kasalath, respectively. These substitutions may explain the change of pI in the glutelin polypeptide between Kinmaze and Kasalath. Since T-1047 in Kinmaze exhibited TaqI restriction enzyme site of TCGA, CAPS maker was designed in this position. The DNA extracted from leaves of 139 F₂ plants of the cross between Kinmaze and Kasalath were used for genetic analysis with

CAPS marker. The glutelins in F₃ seeds obtained from each F₂ plant were analyzed by horizontal IEF system. Recombinants between the CAPS maker of Kinmaze type for GluA-3 and the glutelin subunit band pI6.55 of Kinmaze were not observed. Therefore, we concluded that Glu6 corresponds to GluA-3 clone and encodes the polypeptide with pI6.55 (and pI6.52).

This study was partly supported by Bio-oriented Technology Research Advancement Institution (BRAIN), Japan.

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