Developmental abnormalities of glycosylphosphatidylinositol-anchor-deficient embryos revealed by Cre/loxP system.
One mode used to link membrane proteins to a cell membrane is by means of a special glycolipid anchor termed glycosylphosphatidylinositol (GPI). Pig-a, an X-linked gene, is involved in the first step of GPI-anchor biosynthesis. Disruption of this gene causes cessation of GPI biosynthesis on the endoplasmic reticulum, thereby leading to the absence of GPI-anchored proteins on the cell surface. We have previously reported that mice with high chimerism was never obtained from Pig-a disrupted ES cells, suggesting that GPI-anchored protein(s) may have important roles for mouse development such that the absence of GPI-anchored proteins causes a lethal effect to mice. In this study, this lethal effect has been investigated by using a conditional approach to "knockout" the Pig-a gene. For this, mice harboring a Pig-a gene flanked by two loxP sites (Pig-aflox) were mated with hCMV-Cre transgenic mice, which express Cre recombinase before implantation. The allele disruptions were identified by PCR analysis of embryo yolk sac DNA. Embryos harboring a complete disruption of Pig-a gene ceased to develop beyond the ninth day of gestation. Female embryos in which one Pig-a allele was disrupted by Cre such that only half of the cells in the embryo proper did not express GPI-anchored proteins due to random X inactivation developed until 19 days post coitum (dpc), but showed abnormal phenotypes such as insufficient closure of neural tube and cleft palate. These data further highlight the importance of GPI-anchored proteins during mouse embryonic development.
Nozaki
M
M
Department of Molecular Embryology, Research Institute for Microbial Diseases, Osaka University, Japan.
Ohishi
K
K
Yamada
N
N
Kinoshita
T
T
Nagy
A
A
Takeda
J
J
D000818:Animals; D001921:Brain / Q000002:abnormalities* / Q000196:embryology*; D004622:Embryo, Mammalian / Q000378:metabolism*; D005314:Embryonic and Fetal Development / Q000502:physiology; D005260:Female; D018390:Gene Targeting / Q000379:methods*; D017261:Glycosylphosphatidylinositols / Q000172:deficiency*; D008297:Male; D008565:Membrane Proteins / Q000235:genetics; D051379:Mice; D008822:Mice, Transgenic / Q000235:genetics
D017261:Glycosylphosphatidylinositols; D008565:Membrane Proteins; C080086:phosphatidylinositol glycan-class A protein