IMPC Embryo Data
Each IMPC gene knockout strain is assessed for viability by examination of litters produced from mating heterozygous animals. A strain is declared lethal if no homozygous nulls pups are detected at weaning age. A strain is declared subviable if homozygous null pups constitute less than 12.5% of the litter. For lethal strains, embryos are phenotyped in the embryonic and perinatal lethal pipeline. For embryonic lethal and subviable strains, heterozygotes are phenotyped in the IMPC adult phenotyping pipeline.
IMPC Embryo Phenotyping - Goals and Procedures
With up to one third of knockout strains being embryonic lethal, a systematic unbaised phenotyping pipeline was established to perform morphologic and imaging evaluation of mutant embryos to define the primary perturbations that cause their death. From this important insights are gained into gene function.
IMPC centers funded by the NIH Common fund mechanism are delivering the following for All Lines:
- Heterozygote E12.5 Embryonic LacZ staining ( 2 mutant animals, wt reference images)
For All Embryonic Lethal Lines, gross morphology is assessed at E12.5 to determine if defects occur earlier or later in development. A comprehensive imaging platform is then used to assess dysmorphology at the most appropriate stage:
|E9.5 Gross morphology||at least 2 homs,2 wt||images optional|
|E9.5 OPT screening||at least 2 homs||reconstructions available|
|E14.5-E15.5 Gross morphology||at least 2 homs, 2 wt||images optional|
|E14.5-E15.5 microCT screening||at least 2 homs||reconstructions available|
|E14.5 HREM||at least 3 homs, 1wt||reconstructions available|
|E18.5 Gross morphology||at least 2 homs||images optional|
|E18.5 microCT||at least 2 homs, 2 wt||reconstructions available|
In addition, the NIH is supporting in-depth phenotyping of embryonic lethal lines with three current awardees.
The majority of IMPC knockout strains replace a critical protein coding exon with a LacZ gene expression reporter element. Heterozygote E12.5 embryos from IMPC strains are treated to determine in situ expression of the targeted gene.
See all genes with embryo LacZ images.
Embryo Gross Morphology
WT / Acvr2a
Gross morphology of embryos from lethal and subviable strains highlights which biological systems are impacted when the function of a gene is turned off. The developmental stage selected is determined by an initial assessment.
The embryonic and perinatal lethal pipeline comprises several 3D imaging modalities to quantify aberrant morphology that could not be determined by gross inspection. Images acquired by micro-CT and OPT are available via our Interactive Embryo Viewer (IEV).
These vignettes highlight the utility of embryo phenotyping pipeline and demonstrate how gross morphology, embryonic lacz expression, and high resolution 3D imaging provide insights into developmental biology. Clicking on an image will provide more information.