作者:M. Caspi、R. Atlas、A. Kantor、T. Sapir、O. Reiner
DOI:10.1093/oxfordjournals.hmg.a018911
日期:2000.9.1
Mutations in either LIS1 or DCX are the most common cause for type I lissencephaly. Here we report that LIS1 and DCX interact physically both in vitro and in vivo.Epitope-tagged DCX transiently expressed in COS cellscan be co-immunoprecipitated with endogenous LIS1. Furthermore, endogenous DCX could be co-immunoprecipitated with endogenous LIS1 in embryonic brain extracts, demonstrating an in vivo association. The two protein products also co-localize in transfected cells and in primary neuronal cells. In addition, we demonstrate homodimerization of DCX in vitro. Using fragments of both LIS1 and DCX, the domains of interaction were mapped. LIS1 and DCX interact with tubulin and microtubules. Our results suggest that addition of DCX and LIS1 to tubulin enhances polymerization in an additive fashion. In in vitro competition assays, when LIS1 is added first, DCX competes with LIS1 in its binding to microtubules, but when DCX is added prior to the addition of LIS1 it enhances the binding of LIS1 to microtubules. We conclude that LIS1 and DCX cross-talk is important to microtubule function in the developing cerebral cortex.
LIS1或DCX的突变是导致I型无脑畸形的最常见原因。表位标记的DCX在COS细胞中瞬时表达,可与内源性LIS1共免疫沉淀。此外,在胚胎脑提取物中,内源性 DCX 可与内源性 LIS1 共免疫沉淀,这证明了两者在体内的关联。这两种蛋白产物在转染细胞和原代神经元细胞中也能共定位。此外,我们还在体外证明了 DCX 的同源二聚化。利用 LIS1 和 DCX 的片段,我们绘制了相互作用的结构域图。LIS1 和 DCX 与微管蛋白和微管相互作用。我们的研究结果表明,将 DCX 和 LIS1 添加到微管蛋白中会以相加的方式增强聚合作用。在体外竞争试验中,当首先加入 LIS1 时,DCX 会与 LIS1 竞争与微管的结合,但当在加入 LIS1 之前加入 DCX 时,DCX 会增强 LIS1 与微管的结合。我们的结论是,LIS1和DCX的交叉作用对发育中大脑皮层的微管功能非常重要。