High-throughput discovery of novel developmental phenotypes

Abstract

Approximately one third of all mammalian genes are essential for life. Phenotypes resulting from mouse knockouts of these genes have provided tremendous insight into gene function and congenital disorders. As part of the International Mouse Phenotyping Consortium effort to generate and phenotypically characterize 5000 knockout mouse lines, we have identified 410 lethal genes during the production of the first 1751 unique gene knockouts. Using a standardised phenotyping platform that incorporates high-resolution 3D imaging, we identified novel phenotypes at multiple time points for previously uncharacterized genes and additional phenotypes for genes with previously reported mutant phenotypes. Unexpectedly, our analysis reveals that incomplete penetrance and variable expressivity are common even on a defined genetic background. In addition, we show that human disease genes are enriched for essential genes identified in our screen, thus providing a novel dataset that facilitates prioritization and validation of mutations identified in clinical sequencing efforts.

Glutathione peroxidase 4 inhibits Wnt/β-catenin signaling and regulates dorsal organizer formation in zebrafish embryos

“…On the other hand, variable compensation may also contribute to penetrance and expressivity between intra-and inter-genetic lines. Recently, similar incomplete penetrance and variable expressivity were found in a high-throughput analysis of developmental phenotypes in mice that supported this view (Dickinson et al, 2016). Additionally, genetic knockout and MO-based knockdown have different effects: genetic knockout of gpx4b caused complete loss of Gpx4b protein, while the injected MO might be gradually diluted throughout embryonic development, with insufficient MO remaining to block the translation of zygotic gpx4b mRNA.…”

Calcium at the Center of Cell Signaling: Interplay between Endoplasmic Reticulum, Mitochondria, and Lysosomes

“…These animals are viable and fertile, if maintained in a outbred CD1 strain, although isolated mitochondria from these animals lack Ca 2+ uptake [55]. More consistent with expectations, MCU deletion results in embryonic lethality in the C57BL/6 strain [56] and [114]. This suggests the existence of a compensatory mechanism that allows mitochondrial Ca 2+ uptake in CD1 mice.…”

Highly variable penetrance of abnormal phenotypes in embryonic lethal knockout mice

“…Gene knockout lines produced as part of a systematic programme coordinated by the International Mouse Phenotyping Consortium (http://www.mousephenotype.org) were designated lethal if no homozygous mutants were present amongst a minimum of 28 pups at P14 and sub-viable if their proportion fell below 13% of total offspring 2 . Embryos were harvested from one or more litters at E14.5, fixed in Bouin’s fixative for 24 hours and stored at 4°C in phosphate buffered saline.…”