Deletion of the Na/K-ATPase alpha1-subunit gene (Atp1a1) does not prevent cavitation of the preimplantation mouse embryo.
Increases in Na/K-ATPase activity occur concurrently with the onset of cavitation and are associated with increases in Na(+)-pump subunit mRNA and protein expression. We have hypothesized that the alpha1-isozyme of the Na/K-ATPase is required to mediate blastocyst formation. We have tested this hypothesis by characterizing preimplantation development in mice with a targeted disruption of the Na/K-ATPase alpha1-subunit (Atp1a1) using embryos acquired from matings between Atp1a1 heterozygous mice. Mouse embryos homozygous for a null mutation in the Na/K-ATPase alpha1-subunit gene are able to undergo compaction and cavitation. These findings demonstrate that trophectoderm transport mechanisms are maintained in the absence of the predominant isozyme of the Na(+)-pump that has previously been localized to the basolateral membranes of mammalian trophectoderm cells. The presence of multiple isoforms of Na/K-ATPase alpha- and beta-subunits at the time of cavitation suggests that there may be a degree of genetic redundancy amongst isoforms of the catalytic alpha-subunit that allows blastocyst formation to progress in the absence of the alpha1-subunit.
Barcroft
L C
LC
Department Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati, Cincinnati, OH 45267-0524, USA.
Moseley
A E
AE
Lingrel
J B
JB
Watson
A J
AJ
D000818:Animals; D001755:Blastocyst / Q000166:cytology* / Q000276:immunology / Q000378:metabolism*; D048430:Cell Shape; D048429:Cell Size; D002478:Cells, Cultured; D005260:Female; D017353:Gene Deletion; D005838:Genotype; D006720:Homozygote; D007150:Immunohistochemistry; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D021122:Protein Subunits / Q000172:deficiency* / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000172:deficiency* / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D013997:Time Factors
D021122:Protein Subunits; D000254:Sodium-Potassium-Exchanging ATPase