Phenotypic analysis of Myo10 knockout (Myo10tm2/tm2) mice lacking full-length (motorized) but not brain-specific headless myosin X

Bachg, A. C. et al. (2019) Phenotypic analysis of Myo10 knockout (Myo10tm2/tm2) mice lacking full-length (motorized) but not brain-specific headless myosin X. Scientific Reports, 9, 597. (doi: 10.1038/s41598-018-37160-y) (PMID:30679680) (PMCID:PMC6345916)

Abstract

We investigated the physiological functions of Myo10 (myosin X) using Myo10 reporter knockout (Myo10tm2) mice. Full-length (motorized) Myo10 protein was deleted, but the brain-specific headless (Hdl) isoform (Hdl-Myo10) was still expressed in homozygous mutants. In vitro, we confirmed that Hdl-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 Myo10tm2/tm2 mice. However, reminiscent of Waardenburg syndrome, a neural crest disorder, Myo10tm2/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, Myo10tm2/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).

• Item Type: Articles
• Additional Information: Tis study was supported by the Deutsche Forschungsgemeinschaf (DFG) grant HA 3271/4-1 (PJH), as well as EXC 1003 (Cluster of Excellence 1003), Cells in Motion (CiM), and the IZKF Münster (core unit PIX).
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Machesky, Professor Laura
• Authors: Bachg, A. C., Horsthemke, M., Skryabin, B. V., Klasen, T., Nagelmann, N., Faber, C., Woodham, E., Machesky, L. M., Bachg, S., Stange, R., Jeong, H.-W., Adams, R. H., Bähler, M., and Hanley, P. J.
• College/School: College of Medical Veterinary and Life Sciences > School of Cancer Sciences
• Journal Name: Scientific Reports
• Publisher: Nature Research
• ISSN: 2045-2322
• ISSN (Online): 2045-2322
• Copyright Holders: Copyright © 2019 The Authors
• First Published: First published in Scientific Reports 9(1):597
• Publisher Policy: Reproduced under a Creative Commons License