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Ouabain sensitivity and expression of Na/K‐ATPase α‐ and β‐subunit isoform genes during bovine early development
Author(s) -
Betts Dean H.,
MacPhee Daniel J.,
Kidder Gerald M.,
Watson Andrew J.
Publication year - 1997
Publication title -
molecular reproduction and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.745
H-Index - 105
eISSN - 1098-2795
pISSN - 1040-452X
DOI - 10.1002/(sici)1098-2795(199702)46:2<114::aid-mrd2>3.0.co;2-t
Subject(s) - ouabain , biology , gene isoform , blastocyst , microbiology and biotechnology , protein subunit , embryo , embryogenesis , gene , biochemistry , chemistry , sodium , organic chemistry
The fluid movements that arise during blastocyst formation (cavitation) are, at least in part, driven by the Na/K‐ATPase. In this study, the reverse transcriptase‐polymerase chain reaction (RT‐PCR) was used to survey bovine pre‐attachment embryos for transcripts encoding known isoforms of the Na/K‐ATPase α‐ and β‐ subunits, including isoforms not previously detected during the first week of mammalian development. Transcripts encoding the Na‐K‐ATPase α1, α2, α3 and β2 isoforms were detected throughout bovine preattachment development. This is the first indication that α2, α3 and β2 mRNAs are expressed during this early developmental interval. As in the mouse, β1‐subunit transcripts were not detected until the morula stage and were also present in blastocysts. Thus, in two mammalian species an increase in abundance of β1 isoform transcripts in the morula stage is coincident with the onset of cavitation. Transcripts encoding the recently characterized α4 isoform were not detected. The sensitivity of bovine blastocysts to ouabain (a potent inhibitor of Na/K‐ATPase) was determined by assessing the ability of bovine blastocysts to recover in ouabain supplemental culture medium following cytochalasin‐induced blastocyst collapse. Re‐expansion of bovine blastocysts was inhibited in all ouabain concentrations down to 10 9 M. Mouse blastocysts, in contrast, were sensitive to ouabain at or above 10 3 M. These results have established that transcripts encoding multiple isoforms of both the α and β subunits of the Na/K‐ATPase are expressed throughout early bovine development and that bovine blastocysts display a greater sensitivity to ouabain than murine blastocysts. Future analysis will determine the possible individual and collective roles of these isoforms during blastocyst formation. Mol Reprod Dev 46:114–126, 1997. © 1997 Wiley‐Liss, Inc.