deGrad(sls-Nano2) is an engineered F-box protein that is designed to target the D. melanogaster sls protein for degradation via the ubiquitin pathway; partial degradation of sls protein has been seen when deGrad(sls-Nano2) was tested in transgenic flies. deGrad(sls-Nano2) contains the N-terminal 198 amino acids of D. melanogaster slmb (this includes the F-box domain), fused to 'Sls-Nano2', a nanobody that binds sls (nanobody raised by immunization using a peptide corresponding to the sls Ig13/14 domains) (FBrf0255573).