Kim Soo Young, Ma Jianzhong, Perret Philippe, Li Zhongsen, Thomas Terry L
Department of Biology, Texas A&M University, College Station, TX 77843-3258, USA.
Plant Physiol. 2002 Oct;130(2):688-97. doi: 10.1104/pp.003566.
A small family of novel basic leucine zipper proteins that includes abscisic acid (ABA)-INSENSITIVE 5 (ABI5) binds to the promoter region of the lea class gene Dc3. The factors, referred to as AtDPBFs (Arabidopsis Dc3 promoter-binding factors), were isolated from an immature seed cDNA library. AtDPBFs bind to the embryo specification and ABA-responsive elements in the Dc3 promoter and are unique in that they can interact with cis-elements that do not contain the ACGT core sequence required for the binding of most other plant basic leucine zipper proteins. Analysis of full-length cDNAs showed that at least five different Dc3 promoter-binding factors are present in Arabidopsis seeds; one of these, AtDPBF-1, is identical to ABI5. As expected, AtDPBF-1/ABI5 mRNA is inducible by exogenous ABA in seedlings. Despite the near identity in their basic domains, AtDPBFs are distinct in their DNA-binding, dimerization, and transcriptional activity.
一个包含脱落酸（ABA）不敏感5（ABI5）的新型碱性亮氨酸拉链蛋白小家族与lea类基因Dc3的启动子区域结合。这些被称为AtDPBFs（拟南芥Dc3启动子结合因子）的因子是从未成熟种子cDNA文库中分离出来的。AtDPBFs与Dc3启动子中的胚胎特异性和ABA反应元件结合，其独特之处在于它们可以与大多数其他植物碱性亮氨酸拉链蛋白结合所需的不包含ACGT核心序列的顺式元件相互作用。全长cDNA分析表明，拟南芥种子中至少存在五种不同的Dc3启动子结合因子；其中之一AtDPBF-1与ABI5相同。正如预期的那样，AtDPBF-1/ABI5 mRNA在幼苗中可被外源ABA诱导。尽管它们的碱性结构域几乎相同，但AtDPBFs在DNA结合、二聚化和转录活性方面是不同的。
