Obstetrics & Gynaecology Publications
Expression of Na,K-ATPase alpha and beta subunit genes during preimplantation development of the mouse.
Document Type
Article
Publication Date
1-1-1990
Journal
Developmental genetics
Volume
11
Issue
1
First Page
41
Last Page
48
URL with Digital Object Identifier
http://onlinelibrary.wiley.com/doi/10.1002/dvg.1020110106/abstract
Abstract
Na,K-ATPase is a plasma membrane enzyme that plays a critical role in eutherian blastocoel formation (cavitation) by pumping Na+ into the extracellular space enclosed by the trophectoderm. Previous experiments with the mouse had shown that the alpha (catalytic) subunit of the enzyme becomes detectable by immunocytochemistry in the late morula, just prior to the onset of cavitation. In the present study we have used cDNAs corresponding to three mRNA isoforms of the alpha subunit and a beta subunit to determine which genes are expressed during preimplantation development and to explore the timing of their expression. Of the three alpha subunit cDNAs tested by Northern blot hybridization with blastocyst RNA, only alpha 1 produced a hybridization signal, recognizing a single mRNA about 4 kb in length. This mRNA is relatively abundant in zygotes but barely detectable by the 2-cell stage and then accumulates steadily thereafter to reach its preimplantation maximum in blastocysts. The beta 1 cDNA detected mRNA of about 2.6-2.8 kb. This mRNA is present in zygotes but could not be detected in 2-, 4-, or 8-cell stages; it is present at a low level in late morulae and is abundant in blastocysts. The temporal profile of accumulation of beta 1 mRNA thus matches more closely than does alpha 1 the timing of appearance of the catalytic subunit. This suggests that the beta subunit may regulate production of the holoenzyme and hence the timing of cavitation.