GENOMIC DNA-SEQUENCE OF A RICE GENE CODING FOR A PULLULANASE-TYPE OF STARCH DEBRANCHING ENZYME

A genomic DNA containing a rice (Oryza sativa L., cv. Norin-8) gene co ding for a pullulanase-type starch debranching enzyme (EC 3.2.1.41) wa s sequenced (EMBL/GenBank/DDBJ accession number AB012915). Along the 1 5, 248 bp DNA, the pullulanase gene is split into 26 exons. The four p ullulanase consensus regions are positioned in the middle portion of t he sequence and are separated by long introns and 1-3 exons. Compariso n of the rice cv. Norin-8 pullulanase genomic structure with that of b arley pullulanase (limit dextrinase) (F. Lok et al., EMBL/GenBank/DDBJ accession number AF022725) indicates that most of the pullulanase exo ns are highly conserved. Alignment of the nucleotide bases of rice exo n 8 with those of barley exon 8-intron 8-exon 9 fragment suggests that the 85 bp internal sequence of rice exon 8 was originally an intron, a possibility further indicated by the absence in barley and spinach ( A. Rent et al., EMBL/GenBank/DDBJ accession number X83969) pullulanase s of amino acid residues encoded by the 85 bp fragment. (C) 1998 Elsev ier Science B.V. All rights reserved.