Phenotypic analysis of Myo10 knockout (Myo10tm2/tm2) mice lacking full-length (motorized) but not brain-specific headless myosin X
Phenotypic analysis of Myo10 knockout (Myo10tm2/tm2) mice lacking full-length (motorized) but not brain-specific headless myosin X
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DOI：
10.1038/s41598-018-37160-y
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发表时间：
2019-01-24
影响因子：
4.6
通讯作者：
Hanley, Peter J.
中科院分区：
文献类型：
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作者：
Bachg, Anne C.;Horsthemke, Markus;Hanley, Peter J.
我们使用Myo 10报告基因敲除小鼠（Myo 10（tm 2））研究Myo 10（myosin X）的生理功能。全长（机动）Myo 10蛋白被删除，但脑特异性无头（HdI）亚型（HdI-Myo 10）仍然在纯合突变体中表达。在体外，我们证实，HdI-Myo 10不诱导丝状伪足，但它强烈定位于质膜的MyTH 4-FERM域的独立。丝状伪足诱导Myo 10参与轴突引导，缺乏Myo 10货物蛋白DCC（在结直肠癌中缺失）的小鼠具有严重的连合缺陷，而离体大脑的MRI（磁共振成像）显示Myo 10（tm 2/tm 2）小鼠中的连合完整。然而，让人想起Waardenburg综合征，一种神经嵴疾病，Myo 10（tm 2/tm 2）小鼠表现出色素沉着缺陷（白色腹部斑点）和简单的并指畸形，具有高的外显率（>95%），24%的突变胚胎发育出露脑，一种神经管闭合缺陷。此外，Myo 10（tm 2/tm 2）小鼠一致显示双侧玻璃体血管的持久性，通过MRI和视网膜整体标本显示。原则上，受损的组织清除可能导致玻璃体血管和并指畸形的持续存在。然而，Myo 10缺陷型巨噬细胞在吞噬凋亡或IgG调理的细胞方面没有表现出缺陷。RNA序列分析表明，Myo 10是最强烈表达的非常规肌球蛋白在视网膜血管内皮细胞和表达水平增加4倍之间的P6和P15，当垂直发芽血管生成引起更深的层。然而，成像分离成人突变视网膜没有显示血管化缺陷。总之，Myo 10对产前（神经管闭合和手指形成）和产后发育（玻璃体退化，但不是视网膜血管化）都很重要。
We investigated the physiological functions of Myo10 (myosin X) using Myo10 reporter knockout (Myo10(tm2)) mice. Full-length (motorized) Myo10 protein was deleted, but the brain-specific headless (HdI) isoform (HdI-Myo10) was still expressed in homozygous mutants. In vitro, we confirmed that HdI-Myo10 does not induce filopodia, but it strongly localized to the plasma membrane independent of the MyTH4-FERM domain. Filopodia-inducing Myo10 is implicated in axon guidance and mice lacking the Myo10 cargo protein DCC (deleted in colorectal cancer) have severe commissural defects, whereas MRI (magnetic resonance imaging) of isolated brains revealed intact commissures in Myo10(tm2/tm2) mice. However, reminiscent of Waardenburg syndrome, a neural crest disorder, Myo10(tm2/tm2) mice exhibited pigmentation defects (white belly spots) and simple syndactyly with high penetrance (>95%), and 24% of mutant embryos developed exencephalus, a neural tube closure defect. Furthermore, Myo10(tm2/tm2) mice consistently displayed bilateral persistence of the hyaloid vasculature, revealed by MRI and retinal whole-mount preparations. In principle, impaired tissue clearance could contribute to persistence of hyaloid vasculature and syndactyly. However, Myo10-deficient macrophages exhibited no defects in the phagocytosis of apoptotic or IgG-opsonized cells. RNA sequence analysis showed that Myo10 was the most strongly expressed unconventional myosin in retinal vascular endothelial cells and expression levels increased 4-fold between P6 and P15, when vertical sprouting angiogenesis gives rise to deeper layers. Nevertheless, imaging of isolated adult mutant retinas did not reveal vascularization defects. In summary, Myo10 is important for both prenatal (neural tube closure and digit formation) and postnatal development (hyaloid regression, but not retinal vascularization).