An aptamer peptide (pep4) that binds Cdk2 protein is expressed as a conformationally constrained loop by fusing it to a stable platform molecule (the Escherichia coli trxA protein). The protein is also tagged with a nuclear localization signal (Tag:NLS(Sry-δ)). It is expressed under the control of an Hsp70 promoter.
Flies expressing Zzzz\aptamerhs.cdc2c.pep4.T:Ecol\trxA,T:nls3 using cyclic heat shock from the third larval instar until eclosion often have eye defects.