Okabe T, Watanabe T, Kudo A
Basel Institute for Immunology, Switzerland.
Eur J Immunol. 1992 Jan;22(1):37-43. doi: 10.1002/eji.1830220107.
The VpreB1 protein is thought to be expressed on the surface of pre-B cells in association with lambda 5 and mu heavy chain, and to play an important role on B cell differentiation. The expression of VpreB1 and lambda 5 is pre-B cell specific, and regulated at the initiation of transcription. We have identified at least two sequence-specific DNA-binding proteins which bind to the region -191 to -74 of the promoter of the mouse VpreB1 gene. These DNA-binding proteins also bind to the promoter of the mouse lambda 5 gene. One of the two DNA-binding proteins, called EBB-1, is restricted to pre-B and B cells, but not detected in plasma cells, T cells and cells of other lineages. Transient transfection analysis of reporter constructs revealed that the binding sites of these proteins play a significant role in the activity of the promoter, especially the binding site of EBB-1. Taken together these results suggest that EBB-1 might be one of the crucial factors which regulates a series of intracellular events in B cell differentiation.
VpreB1蛋白被认为与λ5和μ重链一起表达于前B细胞表面，并在B细胞分化中发挥重要作用。VpreB1和λ5的表达具有前B细胞特异性，并在转录起始时受到调控。我们已经鉴定出至少两种序列特异性DNA结合蛋白，它们与小鼠VpreB1基因启动子的-191至-74区域结合。这些DNA结合蛋白也与小鼠λ5基因的启动子结合。这两种DNA结合蛋白之一，称为EBB-1，仅限于前B细胞和B细胞，在浆细胞、T细胞和其他谱系的细胞中未检测到。报告基因构建体的瞬时转染分析表明，这些蛋白的结合位点在启动子活性中起重要作用，尤其是EBB-1的结合位点。综合这些结果表明，EBB-1可能是调节B细胞分化中一系列细胞内事件的关键因素之一。
