Persson C, Mårtensson A, Mårtensson I L
Department of Cell and Molecular Biology, University of Lund, Sweden.
Eur J Immunol. 1998 Mar;28(3):787-98. doi: 10.1002/(SICI)1521-4141(199803)28:03<787::AID-IMMU787>3.0.CO;2-H.
The VpreB and lambda 5 genes encode proteins that associate non-covalently to form the so-called surrogate light (SL) chain. The SL chain complexes with the immunoglobulin heavy chain to form the pre-B cell receptor, which plays a critical role in B cell development. Expression of the murine SL genes is regulated at the level of transcription initiation. Here, we show that a VpreB1 enhancer is located within the 356 bp immediately upstream of the coding sequence. Interestingly, this region exhibits 96% identity to the upstream region of VpreB2. Deletion mapping located the enhancer to between positions -214 and -47 (+1 is the 5'-most transcription initiation site). The enhancer is tissue and differentiation stage specific, and is composed of several DNA elements that are important for its activity. We also show that a transcription factor, early B cell factor, binds to two such elements, and that at least one of these sites is involved in determining enhancer activity.
VpreB基因和lambda 5基因编码的蛋白质通过非共价结合形成所谓的替代轻链（SL链）。SL链与免疫球蛋白重链复合形成前B细胞受体，该受体在B细胞发育中起关键作用。小鼠SL基因的表达在转录起始水平受到调控。在此，我们表明VpreB1增强子位于编码序列上游紧邻的356 bp范围内。有趣的是，该区域与VpreB2的上游区域具有96%的同一性。缺失定位将增强子定位于-214至-47位之间（+1为最靠近5'端的转录起始位点）。该增强子具有组织和分化阶段特异性，由几个对其活性重要的DNA元件组成。我们还表明，一种转录因子，即早期B细胞因子，与其中两个元件结合，并且这些位点中至少有一个参与决定增强子活性。
