CLONING AND SEQUENCE OF A GENE FOR THE HOMOLOG OF THE STEAROYL-COA DESATURASE FROM SALIVARY-GLANDS OF THE TICK AMBLYOMMA-AMERICANUM

A 1488 base pair cDNA clone has been isolated from a cDNA library made from salivary glands from 3-day feeding adult female ticks. The seque nce of this cDNA suggests it is the gene for the tick homologue of the stearoyl CoA desaturase. This gene is expressed in eggs and all feedi ng stages of the adult examined, but appears to be transcribed to an 8 kb mRNA as well as a 1.5 kb mRNA. Because ticks have the ability to s ynthesize monounsaturated fatty acids and demonstrate a large increase in salivary monounsaturated fatty acids during tick feeding, we hypot hesize that stearoyl CoA desaturase may be a key enzyme in the morphog enesis of tick salivary glands during feeding.