A human laterality disorder caused by a homozygous deleterious mutation in MMP21.
A human laterality disorder caused by a homozygous deleterious mutation in MMP21.
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DOI：
10.1136/jmedgenet-2015-103336
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发表时间：
2015-12
影响因子：
4
通讯作者：
Katsanis N
中科院分区：
文献类型：
--
作者：
Perles Z;Moon S;Ta-Shma A;Yaacov B;Francescatto L;Edvardson S;Rein AJ;Elpeleg O;Katsanis N
脊椎动物胚胎的偏侧性是由左右不对称的基因表达决定的，这种基因表达是由胚胎外液流过胚胎结驱动的。这些过程中的缺陷会导致内脏异位，即内脏器官的异常形成和排列，其范围可以从对称性的完全倒置到器官的选择性排列错误。然而，我们对人类偏侧性缺陷的遗传因果关系的理解仍然相对有限。我们对一个有异位症的近亲家系进行了全外显子组测序。为了探究发现的变体的致病潜力，我们使用了一种体内系统，其中通过瞬时抑制和CRISPR/Cas9诱导的缺失来测试候选基因诱导L-R不对称性的潜力。我们还使用体外测定来测试我们的外显子组衍生的候选物与Notch信号传导之间的可能联系。我们确定了一个纯合的2 bp缺失MMP 21，编码基质金属蛋白酶-21，作为唯一的编码突变，与表型隔离。斑马鱼胚胎中mmp 21的瞬时抑制或CRISPR/Cas9介导的缺失诱导了心脏成环缺陷，伴随着侧板中胚层中的偏侧标记物的破坏，并在体外和体内破坏了notch信号传导。我们的数据表明MMP 21的缺失是人类异位症的原因，伴随着Notch信号传导的缺陷。为了支持这一发现，先前在N-乙基-N-亚硝基脲（ENU）诱导的异位症小鼠中鉴定出MMP 21的纯合错义突变。两者合计，这些观察结果表明，基质金属蛋白酶的作用，在建立不对称的器官发育，可能通过调节形态发生信号。
Laterality in the vertebrate embryo is determined by left–right asymmetric gene expression driven by the flow of extraembryonic fluid across the embryonic node. Defects in these processes cause heterotaxy, the abnormal formation and arrangement of visceral organs that can range from complete inversion of symmetry to the selective misarrangement of organs. However, our understanding of the genetic causality for laterality defects in human beings remains relatively limited. We performed whole exome sequencing in a consanguineous family with heterotaxia. To interrogate the pathogenic potential of the discovered variant, we used an in vivo system in which the potential of the candidate gene to induce L-R asymmetry was tested by transient suppression and CRISPR/Cas9-induced deletions. We also used in vitro assays to test a possible link between our exome-derived candidate and Notch signaling. We identified a homozygous 2 bp deletion in MMP21, encoding matrix metalloproteinase-21, as the sole coding mutation that segregated with the phenotype. Transient suppression or CRISPR/Cas9-mediated deletion of mmp21 in zebrafish embryos induced cardiac looping defects, with concomitant disruption of laterality markers in the lateral plate mesoderm and disrupted notch signalling in vitro and in vivo. Our data implicate loss of MMP21 as a cause of heterotaxy in humans with concomitant defects in Notch signaling. In support of this finding, a homozygous missense mutation in MMP21 was identified previously in mice with N-Ethyl-N-Nitrosourea (ENU)-induced heterotaxy. Taken together, these observations suggest a role of matrix metalloproteinases in the establishment of asymmetric organ development, likely through the regulation of morphogenetic signals.