Sekido R, Takagi T, Okanami M, Moribe H, Yamamura M, Higashi Y, Kondoh H
Institute for Molecular and Cellular Biology, Osaka University, Suita, Osaka, Japan.
Gene. 1996 Sep 16;173(2):227-32. doi: 10.1016/0378-1119(96)00185-0.
DeltaEF1 (delta-crystallin/E2-box factor 1) is a widely distributed repressor of transcription which binds at the E2-box sequence, CACCTG. It carries seven zinc fingers (Zf) in two clusters and a homeodomain in the middle as potential DNA-binding domains. We cloned the genomic gene encoding chicken deltaEF1 and analyzed its organization. The gene consisted of nine exons, the N-proximal Zf were encoded by exons 5 through 7, and the C-proximal Zf by exons 8 and 9. Exon 7 also coded for the large middle portion of the protein including the homeodomain. Promoter analysis and RNase-protection assay indicated that the gene is driven by a G+C-rich promoter without a TATA box, and the transcription start points (tsp) cluster around 20 bp from the start codon located in exon 1. cDNA and genomic sequences of the mouse delta EF1 were cloned and compared with the chicken sequence. The deduced amino acid (aa) sequence was highly conserved between the chicken and mouse deltaEF1, no only in DNA-binding motifs but also in other blocks (78% overall aa identity). More recently reported DNA-binding proteins, AREB6 (human) ZEB (human) and BZP (hamster), were attributed to homologues of deltaEF1, among which only AREB6 represented full-length sequence. It was also indicated that rodent deltaEF1 lacked exon 3.
DeltaEF1（δ-晶体蛋白/E2-盒因子1）是一种广泛分布的转录抑制因子，它结合在E2-盒序列CACCTG上。它在两个簇中带有七个锌指（Zf），中间有一个同源结构域作为潜在的DNA结合结构域。我们克隆了编码鸡DeltaEF1的基因组基因并分析了其结构。该基因由九个外显子组成，N端近端锌指由外显子5至7编码，C端近端锌指由外显子8和9编码。外显子7还编码了包括同源结构域在内的蛋白质的大部分中间部分。启动子分析和核糖核酸酶保护试验表明，该基因由一个富含G+C且无TATA盒的启动子驱动，转录起始点（tsp）聚集在位于外显子1的起始密码子上游约20 bp处。克隆了小鼠Delta EF1的cDNA和基因组序列，并与鸡的序列进行了比较。推导的氨基酸（aa）序列在鸡和小鼠DeltaEF1之间高度保守，不仅在DNA结合基序中，而且在其他区域（总体氨基酸同一性为78%）。最近报道的DNA结合蛋白AREB6（人类）、ZEB（人类）和BZP（仓鼠）被认为是DeltaEF1的同源物，其中只有AREB6代表全长序列。还表明啮齿动物DeltaEF1缺少外显子3。
