Characterization of a new rice glutelin gene GluD-1 expressed in the starchy endosperm.
A new glutelin gene, designated GluD-1, has been discovered by comparing the seed storage proteins from 48 japonica and indica rice cultivars on SDS-PAGE gels. Evidence that GluD-1 is a member of the glutelin family was provided by Western blots using anti-glutelin antiserum and by mapping the gene to the chromosomal glutelin gene cluster. The limited GluD-1 size polymorphism among the rice varieties is due to amino acid substitutions rather than to post-transcriptional modification. GluD-1 is maximally expressed in the starchy endosperm starting at 5 d after flowering (DAF) and increasing through 30 DAF, a major difference from the other glutelins which are primarily expressed in the subaleurone from 10-16 DAF. Only about 0.2 kb of the GluD-1 promoter was sufficient to confer inner starchy endosperm-specific expression. The 0.2 kb truncated GluD-1 promoter contains a bifactorial endosperm box consisting of a truncated GCN4 motif (TGA(G/C)TCA) and AAAG Prolamin box (P box), and ACGT and AACA motifs as cis-regulatory elements. Gel retardation assays and trans-activation experiments indicated that the truncated GCN4 and P box are specifically recognized by RISBZ1 b-ZIP and RPBF Dof activators in vitro, respectively, and are synergistically transactivated, indicating that combinatorial interactions of these motifs are involved in essential endosperm-specific regulation. Furthermore, deviation from the cognate GCN4 motif alters tissue-specific expression in the inner starchy endosperm to include other endosperm tissues.
Kawakatsu
Taiji
T
Transgenic Crop Research and Development Center, National Institute of Agrobiological Sciences, 2-1-2 Kan-nondai, Tsukuba, 305-8602, Japan.
Yamamoto
Masayuki P
MP
Hirose
Sakiko
S
Yano
Masahiro
M
Takaiwa
Fumio
F
D018506:Gene Expression Regulation, Plant; D005983:Glutens / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data; D012275:Oryza / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic; D055314:Seed Storage Proteins / Q000235:genetics / Q000378:metabolism; D012639:Seeds / Q000235:genetics / Q000378:metabolism; D013213:Starch / Q000378:metabolism*
D055314:Seed Storage Proteins; D005983:Glutens; D013213:Starch