Germline Saturation Mutagenesis Induces Skeletal Phenotypes in Mice

Proper embryonic and postnatal skeletal development require coordination of myriad complex molecular mechanisms. Disruption of these processes, through genetic mutation, contributes to variation in skeletal development. We developed a high-throughput N-ethyl-N-nitrosourea (ENU)-induced saturation mutagenesis skeletal screening approach in mice to identify genes required for proper skeletal development. Here, we report initial results from live-animal X-ray and dual-energy X-ray absorptiometry (DXA) imaging of 27,607 G3 mice from 806 pedigrees, testing the effects of 32,198 coding/splicing mutations in 13,020 genes. A total of 39.7% of all autosomal genes were severely damaged or destroyed by mutations tested twice or more in the homozygous state. Results from our study demonstrate the feasibility of in vivo mutagenesis to identify mouse models of skeletal disease. Furthermore, our study demonstrates how ENU mutagenesis provides opportunities to create and characterize putative hypomorphic mutations in developmentally essential genes. Finally, we present a viable mouse model and case report of recessive skeletal disease caused by mutations in FAM20B. Results from this study, including engineered mouse models, are made publicly available via the online Mutagenetix database. (c) 2021 American Society for Bone and Mineral Research (ASBMR).

Automated summary

Proper skeletal development requires coordination of complex molecular mechanisms, and disruption of these processes through genetic mutation can lead to skeletal abnormalities. The study successfully developed a high-throughput skeletal screening approach to identify genes essential for skeletal development, showing the feasibility of in vivo mutagenesis to create mouse models of skeletal disease and characterize mutations in developmentally essential genes like FAM20B. Results and engineered mouse models from the study are publicly available through the Mutagenetix database.