Ou-Lee T M, Turgeon R, Wu R
Section of Plant Biology, Cornell University, Ithaca, NY 14853.
Proc Natl Acad Sci U S A. 1988 Sep;85(17):6366-9. doi: 10.1073/pnas.85.17.6366.
The interaction between the DNA sequences of an alpha-amylase (EC 3.2.1.1) gene and a tissue-specific factor induced in rice (Oryza sativa L.) aleurone tissue by gibberellin was studied. DNA mobility-shift during electrophoresis indicated that a 500-base-pair sequence (HS500) of a rice alpha-amylase genomic clone (OSamy-a) specifically interacted with a factor from gibberellin-induced rice aleurone tissue. The amount of complex formed between the HS500 DNA fragment and the gibberellin-induced factor increased in proportion to increasing amounts of aleurone extract and decreased with the addition of unlabeled HS500 DNA fragment. A specific segment of the HS500 fragment was protected from exonuclease III digestion by protein(s) in the aleurone extract, revealing the approximate position of the protein-DNA interaction. In the protected region, there is a direct repeat that overlaps with a potential stem-loop structure. Protein in extracts from leaves, roots, or deembryonated seeds incubated without gibberellin A3 did not bind to the HS500 DNA fragment. However, the binding factor was induced in deembryonated seeds when exogenous gibberellin A3 was added during seed imbibition. This suggests that activation of alpha-amylase synthesis by gibberellin may be mediated by the formation of a factor that interacts with a specific sequence of the alpha-amylase gene.
研究了水稻（Oryza sativa L.）糊粉层组织中由赤霉素诱导的α-淀粉酶（EC 3.2.1.1）基因的DNA序列与组织特异性因子之间的相互作用。电泳过程中的DNA迁移率变动表明，水稻α-淀粉酶基因组克隆（OSamy-a）的一个500碱基对序列（HS500）与来自赤霉素诱导的水稻糊粉层组织的一种因子发生特异性相互作用。HS500 DNA片段与赤霉素诱导因子形成的复合物的量随糊粉层提取物量的增加而成比例增加，并随着未标记的HS500 DNA片段的加入而减少。HS500片段的一个特定区段受到糊粉层提取物中蛋白质对外切核酸酶III消化的保护，揭示了蛋白质-DNA相互作用的大致位置。在受保护区域，存在一个与潜在茎环结构重叠的直接重复序列。未经赤霉素A3处理的叶片、根或去胚种子提取物中的蛋白质不与HS500 DNA片段结合。然而，在种子吸胀期间添加外源赤霉素A3时，去胚种子中可诱导产生结合因子。这表明赤霉素对α-淀粉酶合成的激活可能是由一种与α-淀粉酶基因特定序列相互作用的因子的形成介导的。
