TARGETING CYCLIN-DEPENDENT KINASES IN DROSOPHILA WITH PEPTIDE APTAMERS

Two-hybrid technology provides a simple way to isolate small peptide a ptamers that specifically recognize and strongly bind to a protein of interest. These aptamers have the potential to dominantly interfere wi th specific activities of their target proteins and, therefore, could be used as in vivo inhibitors. Here we explore the ability to use pept ide aptamers as in vivo inhibitors by expressing aptamers directed aga inst cell cycle regulators in Drosophila. We expressed two peptide apt amers, each of which specifically recognizes one of the two essential cyclin-dependent kinases (Cdks), DmCdk1 and DmCdk2, in Drosophila. Exp ression of each Cdk aptamer during organogenesis caused adult eye defe cts typical of those caused by cell cycle inhibition. Co-overexpressio n of DmCdk1 or DmCdk2 resulted in suppression of the eye phenotype, in dicating that each aptamer interacts with a Cdk target in vivo and sug gesting that these peptides disrupt normal eye development by inhibiti ng Cdk function. Moreover, the specificity of each aptamer for one of the two Cdks as determined in two-hybrid assays was retained in Drosop hila. Combined, our results demonstrate that peptide aptamers generate d by yeast two-hybrid methods can serve as inhibitory reagents to targ et specific proteins in vivo.