De Paolis A, Sabatini S, De Pascalis L, Costantino P, Capone I
Istituto Pasteur Fondazione Cenci Bolognetti, Dip. Genetica e Biologia Molecolare, Università di Roma La Sapienza, Italy.
Plant J. 1996 Aug;10(2):215-23. doi: 10.1046/j.1365-313x.1996.10020215.x.
A protein which binds to the regulatory domain B necessary for expression of the plant oncogene rolB in (root) meristems contains a single zinc finger of a novel type conserved in dicots and monocots. Band shift analysis revealed the presence in tobacco nuclei of a protein selectively binding to domain B, a tetramer of which was used to isolate a cDNA (NtBBF1, Nicotiana tabacum rolB domain B Factor 1) from a tobacco expression library. The corresponding genomic clone was also isolated. The protein encoded by NtBBF1 contains a single C2C2 zinc finger, and its target sequence in domain B was identified by means of mutagenized oligonucleotides. The DNA-binding capability of the zinc finger was assessed by means of a fusion of this latter with the glutathione-S-transferase protein, that was shown to bind the same target sequence as NtBBF1. A number of other tobacco cDNAs encoding different proteins with a domain (BBF domain) encompassing the zinc finger identical to NtBBF1 were also isolated. Furthermore, a cDNA encoding a protein with an almost identical single zinc finger was isolated from Arabidopsis. A very closely related zinc finger has very recently been identified in maize transcription factors and termed the Dof domain. It is proposed that the tobacco, Arabidopsis and maize BBF/Dof domain proteins are members of a new broad family of plant transcription factors acting through a single zinc finger widely utilized in the plant kingdom.
一种与植物致癌基因rolB在（根）分生组织中表达所必需的调控结构域B结合的蛋白质，含有一个在双子叶植物和单子叶植物中保守的新型单锌指结构。凝胶迁移分析显示烟草细胞核中存在一种与结构域B选择性结合的蛋白质，其四聚体被用于从烟草表达文库中分离出一个cDNA（NtBBF1，烟草rolB结构域B因子1）。相应的基因组克隆也被分离出来。NtBBF1编码的蛋白质含有一个单一的C2C2锌指结构，其在结构域B中的靶序列通过诱变寡核苷酸得以鉴定。锌指的DNA结合能力通过将其与谷胱甘肽-S-转移酶蛋白融合来评估，结果表明该融合蛋白能结合与NtBBF1相同的靶序列。还分离出了许多其他烟草cDNA，它们编码的不同蛋白质带有一个与NtBBF1相同的包含锌指结构的结构域（BBF结构域）。此外，从拟南芥中分离出了一个编码具有几乎相同单锌指结构蛋白质的cDNA。最近在玉米转录因子中鉴定出了一个非常相似的锌指结构，并将其命名为Dof结构域。有人提出，烟草、拟南芥和玉米的BBF/Dof结构域蛋白是一个新的广泛的植物转录因子家族的成员，它们通过植物界广泛使用的单一锌指发挥作用。
