The glycosylphosphatidylinositol (GPI) anchor attaches nearly 150 proteins to the cell membrane. Patients with pathogenic variants in GPI biosynthesis genes develop diverse phenotypes including seizures, dysmorphic facial features and cleft palate through an unknown mechanism. We identified a novel mouse mutant (cleft lip/palate, edema and exencephaly; Clpex) with a hypo-morphic mutation in Post-Glycophosphatidylinositol Attachment to Proteins-2 (Pgap2), a component of the GPI biosynthesis pathway. The Clpex mutation decreases surface GPI expression. Surprisingly, Pgap2 showed tissue specific expression with enrichment in the brain and face. We found the Clpex phenotype is due to apoptosis of neural crest cells (NCCs) and the cranial neuroepithelium. We showed folinic acid supplementation in utero can partially rescue the cleft lip phenotype. Finally, we generated a novel mouse model of NCC-specific total GPI deficiency. These mutants developed median cleft lip and palate demonstrating a previously undocumented cell autonomous role for GPI biosynthesis in NCC development.
Sequencing data have been submitted to GEO (Clpex exome seq: GSE131920 and RNA-Seq: GSE131919)
Transcriptome profiling of Embryonic day 9.5 WT and Clpex mutant miceNCBI Gene Expression Omnibus, GSE131919.
Exome sequencing identified mutations in clpex mouse mutantsNCBI Gene Expression Omnibus, GSE131920.
- Rolf W Stottmann
- Marshall Lukacs
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Animal experimentation: This study was performed in strict accordance with the recommendations in the Guide for the Care and Use of Laboratory Animals of the National Institutes of Health. All of the animals were handled according to approved institutional animal care and use committee (IACUC) protocol #2016-0098 of the Cincinnati Children's Hospital Medical Center. All euthanasia was performed after isoflourane sedation, and every effort was made to minimize suffering.
- Joseph G Gleeson, Howard Hughes Medical Institute, The Rockefeller University, United States
© 2019, Lukacs et al.
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