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Disruption of the murine CTP: phosphoethanolamine cytidylyltransferase gene causes embryonic lethality
Author(s) -
Fullerton Morgan D,
Zhu Lin,
Vance Dennis E,
Bakovic Marica
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.5.a950
Subject(s) - phosphatidylethanolamine , phosphocholine , biology , enzyme , ethanolamine , microbiology and biotechnology , phosphatidylcholine , biochemistry , phospholipid , knockout mouse , biosynthesis , gene , chemistry , membrane
The CDP: ethanolamine (Kennedy) pathway is responsible for the de novo biosynthesis of phosphatidylethanolamine (PE) and ethanolamine plasmalogens, where diacyl‐ and alkylacylglycerol are coupled with CDP‐ethanolamine for their production respectively. We have disrupted the mouse gene encoding the rate‐limiting enzyme in this pathway, CTP: phosphoethanolamine cytidylyltransferase (Pcyt2) by replacing a 2.8kb region, including the promoter region and exons 1–3 with a Neomycin cassette. Upon inter‐crossing of Pcyt2+/‐ animals we obtained low litter sizes and unexpected Mendelian frequencies. From a total of 111 pups, 40% Pcyt2+/+ and 60% Pcyt2 +/− and no knockout pups were genotyped. Examination of embryos from E13.5 and E10.5 resulted in similar patterns of distribution, with no knockout embryos identified. This demonstrates that Pcyt2−/− mice are embryonic lethal prior to at least E10.5. Comparative mRNA analyses, immunoblotting and enzyme activity assays between Pcyt2+/− and controls have revealed a tissue specific gene dosage effect with significant differences between Pcyt2+/− and controls (30–50%). In vitro enzyme activities for PE methyltransferase, a liver specific enzyme that converts PE to phosphatidylcholine reveals slightly up‐regulated activities in Pcyt2+/− animals. Phospholipid composition and content of Pcyt2+/− liver, heart and brain show no significant differences from controls. This demonstrates the importance of the Kennedy pathway for the production of ethanolamine phospholipids.