Zentrum für Molekulare Neurobiologie, Universitätsklinikum Hamburg-Eppendorf, D-20246 Hamburg, Germany.
BMC Mol Biol. 2009 Dec 14;10:107. doi: 10.1186/1471-2199-10-107.
The neural cell adhesion molecule L1 plays a crucial role in development and plasticity of the nervous system. Neural cells thus require precise control of L1 expression.
We identified a full binding site for nuclear factor I (NFI) transcription factors in the regulatory region of the mouse L1 gene. Electrophoretic mobility shift assay (EMSA) showed binding of nuclear factor I-A (NFI-A) to this site. Moreover, for a brain-specific isoform of NFI-A (NFI-A bs), we confirmed the interaction in vivo using chromatin immunoprecipitation (ChIP). Reporter gene assays showed that in neuroblastoma cells, overexpression of NFI-A bs repressed L1 expression threefold.
Our findings suggest that NFI-A, in particular its brain-specific isoform, represses L1 gene expression, and might act as a second silencer of L1 in addition to the neural restrictive silencer factor (NRSF).
神经细胞黏附分子 L1 在神经系统的发育和可塑性中起着至关重要的作用。因此,神经细胞需要精确控制 L1 的表达。
我们在小鼠 L1 基因的调控区域中鉴定出一个完整的核因子 I(NFI)转录因子结合位点。电泳迁移率变动分析(EMSA)显示核因子 I-A(NFI-A)与该位点结合。此外,对于 NFI-A 的一种脑特异性同工型(NFI-A bs),我们使用染色质免疫沉淀(ChIP)在体内证实了相互作用。报告基因分析表明,在神经母细胞瘤细胞中,NFI-A bs 的过表达将 L1 表达抑制了三倍。
我们的发现表明,NFI-A,特别是其脑特异性同工型,抑制 L1 基因表达,并可能除神经限制沉默因子(NRSF)之外,作为 L1 的第二个沉默子发挥作用。