The mouse homeobox gene Not is required for caudal notochord development and affected 1725 by the truncate mutation
The mouse homeobox gene Not is required for caudal notochord development and affected 1725 by the truncate mutation
复制标题
DOI：
10.1101/gad.303504
复制
发表时间：
2004-07-15
影响因子：
10.5
通讯作者：
Gossler, A
中科院分区：
文献类型：
--
作者：
Ben Abdelkhalek, H;Beckers, A;Gossler, A
斑马鱼的浮头基因（flh）编码一种同源结构域蛋白质，它是沿着沿着整个体轴形成脊索所必需的。flh直向同源物，称为Not基因，已经从鸡和非洲爪蟾中分离出来，但尚未鉴定出哺乳动物直向同源物。截短型突变是一种常染色体隐性突变，特异性地破坏小鼠尾侧脊索的发育。在这里，我们证明了截断引起的突变，在小鼠的基因。截短等位基因（Not（tc））在Not的同源框中含有点突变，其将螺旋1中的保守苯丙氨酸残基改变为半胱氨酸（F20C），并且显著地使同源结构域不稳定。纯合tc胚胎干（ES）细胞的一个等位基因中F20C的逆转足以恢复完全ES细胞衍生胚胎的正常脊索形成。我们已经产生了一个有针对性的突变不是通过测序的大部分的非编码序列，包括同源框与eGFP基因。Not（eGFP/eGFP）、Not（eGFP/tc）和Not（tc/tc）胚胎的表型非常相似，但Not（eGFP/eGFP）胚胎的表型比Not（tc/tc）胚胎的表型略严重。这证实了truncate和Not的等位性，并表明tc不是完全无效等位基因。在Foxa2和T突变体胚胎中不表达被废除，这表明在脊索发育过程中不作用于这两个基因的下游。这是相反的斑马鱼胚胎，其中flh相互作用与nt1（斑马鱼T）在一个监管回路，是必不可少的整个脊索的发展，并表明不同的遗传控制电路在不同的脊椎动物物种脊索形成过程中的行为。
The floating head (flh) gene in zebrafish encodes a homeodomain protein, which is essential for notochord formation along the entire body axis. flh orthologs, termed Not genes, have been isolated from chick and Xenopus, but no mammalian ortholog has yet been identified. Truncate (tc) is an autosomal recessive mutation in mouse that specifically disrupts the development of the caudal notochord. Here, we demonstrate that truncate arose by a mutation in the mouse Not gene. The truncate allele (Not(tc)) contains a point mutation in the homeobox of Not that changes a conserved Phenylalanine residue in helix 1 to a Cysteine (F20C), and significantly destabilizes the homeodomain. Reversion of F20C in one allele of homozygous tc embryonic stem (ES) cells is sufficient to restore normal notochord formation in completely ES cell-derived embryos. We have generated a targeted mutation of Not by replacing-most of the Not coding sequence, including the homeobox with the eGFP gene. The phenotype of Not(eGFP/eGFP), Not(eGFP/tc), and Not(tc/tc) embryos is very similar but slightly more severe in Not(eGFP/eGFP) than in Not(tc/tc) embryos. This confirms allelism of truncate and Not, and indicates that tc is nota complete null allele. Not expression is abolished in Foxa2 and T mutant embryos, suggesting that Not acts downstream of both genes during notochord development. This is in contrast to zebrafish embryos, in which flh interacts with nt1 (zebrafish T) in a regulatory loop and is essential for development of the entire notochord, and suggests that different genetic control circuits act in different vertebrate species during notochord formation.