MOLECULAR-CLONING AND CHARACTERIZATION OF SMALL AND LARGE SUBUNITS OFADP-GLUCOSE PYROPHOSPHORYLASE FROM ORIENTAL MELON

We isolated three cDNAs encoding one small subunit and two large subun its of ADP-glucose pyrophosphorylase (AGP) from oriental melon, msf1 e ncoding the small subunit was 2,027 bp in length, and mlf1 and mlf2 en coding the large subunits were 2,009 and 2,227 bp, respectively. Each of the three clones had a long, uninterrupted open reading frame, deri ving 57-58 kDa polypeptide, The strongest expression of msf1 occurred in leaves, and a relatively weak expression in roots and stems. mlf1 w as highly expressed in stems and roots, whereas the expression was muc h weaker in leaves. The expression pattern of mlf2 was similar to that of msf1, but the expression level of mlf2 transcripts was much lower than that of msf1 transcripts. In fruits, msf1, miff, and mlf2 were ex pressed in all stages investigated with a similar expression profile. During fruit development, all three genes showed the highest expressio n at the early stage, and the transcripts decreased as the fruits matu red.