New mode of DNA binding of multi-zinc finger transcription factors:: δEF1 family members bind with two hands to two target sites
New mode of DNA binding of multi-zinc finger transcription factors:: δEF1 family members bind with two hands to two target sites
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DOI：
10.1093/emboj/18.18.5073
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发表时间：
1999-09-15
期刊：
影响因子：
11.4
通讯作者：
Huylebroeck, D
中科院分区：
文献类型：
--
作者：
Remacle, JE;Kraft, H;Huylebroeck, D
SIP 1，一种Smad相互作用蛋白，和delta EF 1，一种参与骨骼和T细胞发育的转录抑制因子，属于同一个DNA结合蛋白家族。SIP 1和Δ EF 1含有两个分开的锌指簇，一个是N-末端，一个是C-末端，这些簇显示出高度的序列同源性，并且在SIP 1和Δ EF 1之间高度保守。每个锌指簇独立地结合5 ′-CACCT序列。然而，候选靶基因如非洲爪蟾Xbra 2和人α 4-整联蛋白和E-钙粘蛋白的启动子区中全长SIP 1和Δ EF 1的高亲和力结合位点是由一个CACCT和一个CACCTG序列组成的二分元件，其方向和间隔可以变化。使用转基因非洲爪蟾胚胎，我们证明了这两个序列的完整性对于Xbra 2启动子驱动的报告基因的正确空间表达是必需的。这两个锌指簇必须是完整的SIP 1的高亲和力结合到DNA和其最佳的阻遏活性。我们的结果表明，SIP 1作为单体结合，并将一个靶序列与第一个锌指簇接触，另一个与第二个锌指簇接触。我们的工作重新定义了最佳的结合位点，因此，候选靶基因的脊椎动物成员的三角洲EF 1家庭。
SIP1, a Smad-interacting protein, and delta EF1, a transcriptional repressor involved in skeletal and T-cell development, belong to the same family of DNA binding proteins. SIP1 and delta EF1 contain two separated clusters of zinc fingers, one N-terminal and one C-terminal, These clusters show high sequence homology and are highly conserved between SIP1 and delta EF1, Each zinc finger cluster binds independently to a 5'-CACCT sequence. However, high-affinity binding sites for full-length SIP1 and delta EF1 in the promoter regions of candidate target genes like Xenopus Xbra2, and human alpha 4-integrin and E-cadherin, are bipartite elements composed of one CACCT and one CACCTG sequence, the orientation and spacing of which can vary, Using transgenic Xenopus embryos, we demonstrate that the integrity of these two sequences is necessary for correct spatial expression of a Xbra2 promoter-driven reporter gene. Both zinc finger clusters must be intact for the high-affinity binding of SIP1 to DNA and for its optimal repressor activity. Our results show that SIP1 binds as monomer and contacts one target sequence with the first zinc finger cluster, and the other with the second cluster. Our work redefines the optimal binding site and, consequently, candidate target genes for vertebrate members of the delta EF1 family.