CLONING AND TRANSCRIPTIONAL REGULATION OF THE GENE ENCODING THE VACUOLAR H-ATPASE B-SUBUNIT OF DICTYOSTELIUM-DISCOIDEUM()

The main function of vacuolar H+ ATPases in eukaryotic cells is to gen erate proton and electrochemical gradients across the membrane of inne r compartments. We have isolated the gene encoding the B subunit of Di ctyostelium discoideum vacuolar H+ ATPase (vatB) and analyzed its tran scriptional regulation, The deduced protein comprises 493 amino acids with a calculated molecular mass of 54 874 Da. The predicted protein s equence is highly homologous to previously determined V/H+ ATPase B su bunit sequences. The protein is encoded by a single gene in the Dictyo stelium genome, The gene is maximally expressed during growth and it d ecreases during the first hours of development. Gene expression is rap idly enhanced by phagocytosis, but not by fluid-phase endocytosis. Aci dic and alkaline conditions affect vatB gene expression differently. ( C) 1997 Federation of European Biochemical Societies.