Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology, Ikeda 563-8577, Japan.
Sapporo Division, Cosmo Bio Co. Ltd., Otaru 047-0261, Japan.
Poult Sci. 2021 Feb;100(2):452-460. doi: 10.1016/j.psj.2020.10.026. Epub 2020 Nov 2.
Ovomucoid is a major egg white protein which is considered as the most dominant allergen in chicken eggs. Owing to the difficulty of separating ovomucoid from egg whites, researchers have adopted genetic deletion for development of hypoallergenic eggs. Previously, we used CRISPR/Cas9 to establish chickens with ovomucoid gene (OVM) mutations, but it remained unknown whether such hens could produce eggs at maturity. Here, we have reported on eggs laid by OVM-targeted hens. Except for watery egg whites, the eggs had no evident abnormalities. Real-time PCR revealed alternative splicing of OVM mRNA in hens, but their expression was limited. Immunoblotting detected neither mature ovomucoid nor ovomucoid-truncated splicing variants in egg whites. Sixteen chicks hatched from 28 fertilized eggs laid by OVM-targeted hens, and fourteen of the sixteen chicks demonstrated healthy growth. Taken together, our results demonstrated that OVM knockout could almost completely eliminate ovomucoid from eggs, without abolishing fertility. Thus, the eggs developed in this study have potential as a hypoallergenic food source for most patients with egg allergies.
卵类黏蛋白是一种主要的蛋清蛋白，被认为是鸡蛋中最主要的过敏原。由于卵类黏蛋白难以从蛋清中分离出来，研究人员采用基因缺失的方法来开发低致敏性鸡蛋。此前，我们使用 CRISPR/Cas9 技术建立了卵类黏蛋白基因（OVM）突变的鸡，但这些母鸡是否能在成熟时产蛋仍不清楚。在这里，我们报告了 OVM 靶向母鸡所产的蛋。除了蛋清稀薄外，这些蛋没有明显的异常。实时 PCR 显示母鸡 OVM mRNA 发生了选择性剪接，但表达受到限制。免疫印迹检测不到卵清蛋白中的成熟卵类黏蛋白或卵类黏蛋白截断的剪接变体。从 28 枚 OVM 靶向母鸡所产的受精卵中孵化出 16 只小鸡，其中 14 只小鸡生长健康。综上所述，我们的结果表明，OVM 敲除几乎可以完全消除鸡蛋中的卵类黏蛋白，而不会降低其生育能力。因此，本研究中开发的鸡蛋有可能成为大多数鸡蛋过敏患者的低致敏性食物来源。
