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Cloning and sequence of a gene for a homologue of the C subunit of the V-ATPase from the salivary gland of the tickAmblyomma americanum(L.)


Dr Richard C. Essenberg Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK 74078, USA.


A 1084 base pair partial cDNA showing similarity to the C subunit of the vacuolar ATPase (V-ATPase) was isolated on a clone from a cDNA library made from salivary glands from 3-day-old feeding adultAmblyomma americanum(L.) female ticks. The 5′ end was completed using primer extension and the two pieces joined to form a complete cDNA of 1373 bp. This mRNA is expressed in embryos and the salivary glands of unfed adults and adult females at all stages of feeding. Specific inhibitors of the V-ATPase decrease the rate of dopamine-stimulated secretion of isolated salivary glands, but not as much as ouabain, an inhibitor of the Na+, K+ ATPase, indicating that a V-ATPase may participate in the mechanism of salivary fluid secretion inA. americanum, but the volume of saliva secreted is more dependent on an active Na+, K+ ATPase.

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