[8] Use of expression of antisense mRNA for proprotein convertases 1 and 2 in prohormone processing

Publisher Summary Studies using antisense inhibition have been criticized because of the possible nonspecific cellular effects complicating interpretation of the results. In light of these concerns, several controls have been performed to ensure that the effects of antisense expression on the processing of pro-cholecystokinin (CCK) are specific. The two most important controls performed were to measure the effects of antisense expression on target messenger ribonucleic acid (mRNA) and target protein. Another control that was performed was to measure the effect of polycystin 2 (PC2) message and protein level in antisense PC1-transfected cells and vice versa. Although PC1 and PC2 are homologous genes within the same family of endoproteases, the effect of antisense is specific for each. These observations suggest that the effect of antisense on the RNA level is complex but specific and may occur at multiple levels to produce inhibition of the protein product. Knowledge of the actual enzymes responsible for prohormone cleavages in specific tissues lags behind progress in other areas of the peptide hormone field owing to the technical difficulty of identification, isolation, characterization, and inhibition of these enzymes. As important as the PC enzymes appear to be, it is possible that proteases other than the PCs are involved in prohormone processing.