Targeted mutagenesis of Lis1 disrupts cortical development and LIS1 homodimerization
Targeted mutagenesis of Lis1 disrupts cortical development and LIS1 homodimerization
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DOI：
10.1073/pnas.101122598
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发表时间：
2001-05-22
影响因子：
11.1
通讯作者：
Reiner, O
中科院分区：
文献类型：
--
作者：
Cahana, A;Escamez, T;Reiner, O
无脑畸形是一种严重的人类大脑畸形。为了研究无脑畸形（LIS 1）基因突变的功能，我们删除了小鼠LIS 1基因的第一个编码外显子。缺失导致从第二个甲硫氨酸起始的较短蛋白质（sLIS 1），这是一种独特的情况，因为大多数LIS 1突变导致无效等位基因。这种突变模拟了一个轻度无脑回畸形患者的突变。纯合子是早期致死的，尽管杂合子是可存活和可育的。最引人注目的是，皮质神经元和放射状胶质细胞的形态在发育中的皮质中是异常的，并且神经元迁移更慢。据我们所知，这是第一次证明Lis 1突变后迁移神经元中的细胞异常。此外，皮质板分裂和丘脑皮质神经支配也异常。在生物化学上，突变蛋白不能二聚化，并且酶活性在胚胎中升高，从而证明了LIS 1作为PAF-AH的亚基的体内作用。这种突变使我们能够确定对LIS 1剂量敏感的功能层次，从而促进我们对LIS 1在发育皮层中的作用的理解。
Lissencephaly is a severe brain malformation in humans. To study the function of the gene mutated in lissencephaly (LIS1), we deleted the first coding exon from the mouse Lis1 gene. The deletion resulted in a shorter protein (sLIS1) that initiates from the second methionine, a unique situation because most LIS1 mutations result in a null allele. This mutation mimics a mutation described in one lissencephaly patient with a milder phenotype. Homozygotes are early lethal, although heterozygotes are viable and fertile. Most strikingly, the morphology of cortical neurons and radial glia is aberrant in the developing cortex, and the neurons migrate more slowly. This is the first demonstration, to our knowledge, of a cellular abnormality in the migrating neurons after Lis1 mutation. Moreover, cortical plate splitting and thalomocortical innervation are also abnormal. Biochemically, the mutant protein is not capable of dimerization, and enzymatic activity is elevated in the embryos, thus a demonstration of the in vivo role of LIS1 as a subunit of PAF-AH. This mutation allows us to determine a hierarchy of functions that are sensitive to LIS1 dosage, thus promoting our understanding of the role of LIS1 in the developing cortex.