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Molecular characterization and expression of the (Na+ + K+)‐ATPase alpha‐subunit in Drosophila melanogaster.
Author(s) -
Lebovitz R. M.,
Takeyasu K.,
Fambrough D. M.
Publication year - 1989
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1989.tb03364.x
Subject(s) - ouabain , biology , drosophila melanogaster , microbiology and biotechnology , sodium , genetics , chemistry , gene , organic chemistry
The (Na+ + K+)‐ATPase (sodium pump) is an ouabain‐sensitive, electrogenic ion pump responsible for maintaining the balance of sodium and potassium ions in almost all animal cells. Robust, ouabain‐sensitive rubidium uptake, indicative of the sodium pump, was found in tissue‐cultured Drosophila cells, and both larvae and adults die when fed a diet containing ouabain. A monoclonal antibody to the avian sodium pump alpha‐subunit was found to cross‐react with the Drosophila sodium pump alpha‐subunit. Immunofluorescence microscopy was used to obtain a semi‐quantitative view of the expression of the sodium pump in Drosophila tissues: high levels of the sodium pump were detected in malpighian tubules, indirect flight muscles and tubular muscles, and throughout the nervous system. The cDNA encoding this sodium pump alpha‐subunit in Drosophila melanogaster was cloned, sequenced and expressed in mouse L cells. At the amino acid level, its deduced sequence of 1038 residues (the first such sequence for an invertebrate) is approximately 80% similar to alpha‐subunit sequences reported for vertebrates. Only one gene was found in Drosophila, located on the third chromosome at position 93B. A restriction site polymorphism has been found, and several mutations exist that may involve the alpha‐subunit gene.