Wadman I A, Osada H, Grütz G G, Agulnick A D, Westphal H, Forster A, Rabbitts T H
MRC Laboratory of Molecular Biology, Cambridge, UK.
EMBO J. 1997 Jun 2;16(11):3145-57. doi: 10.1093/emboj/16.11.3145.
The LIM-only protein Lmo2, activated by chromosomal translocations in T-cell leukaemias, is normally expressed in haematopoiesis. It interacts with TAL1 and GATA-1 proteins, but the function of the interaction is unexplained. We now show that in erythroid cells Lmo2 forms a novel DNA-binding complex, with GATA-1, TAL1 and E2A, and the recently identified LIM-binding protein Ldb1/NLI. This oligomeric complex binds to a unique, bipartite DNA motif comprising an E-box, CAGGTG, followed approximately 9 bp downstream by a GATA site. In vivo assembly of the DNA-binding complex requires interaction of all five proteins and establishes a transcriptional transactivating complex. These data demonstrate one function for the LIM-binding protein Ldb1 and establish a function for the LIM-only protein Lmo2 as an obligatory component of an oligomeric, DNA-binding complex which may play a role in haematopoiesis.
仅含LIM结构域的蛋白Lmo2在T细胞白血病中因染色体易位而被激活，它通常在造血过程中表达。它与TAL1和GATA-1蛋白相互作用，但其相互作用的功能尚不清楚。我们现在表明，在红系细胞中，Lmo2与GATA-1、TAL1、E2A以及最近鉴定出的LIM结合蛋白Ldb1/NLI形成一种新型的DNA结合复合物。这种寡聚复合物结合到一个独特的二分DNA基序上，该基序包含一个E盒（CAGGTG），在其下游约9个碱基对处接着一个GATA位点。DNA结合复合物的体内组装需要所有这五种蛋白的相互作用，并形成一个转录反式激活复合物。这些数据证明了LIM结合蛋白Ldb1的一种功能，并确立了仅含LIM结构域的蛋白Lmo2作为一种寡聚DNA结合复合物的必需组分的功能，该复合物可能在造血过程中发挥作用。
