Translational control in the mealworm, Tenebrio molitor

ONE of the best known examples of translational control in a eukaryotic system comes from studies on the mealworm, Tenebrio molitor, in which control of the synthesis of adult cuticular proteins at the translational level has been proposed1–7. From experiments using actinomycin D, it was concluded that the mRNAs for some of the adult cuticular proteins were synthesised by the first day of pupation1. To translate these mRNAs in vitro on first day polysomes, however, the tRNA and enzyme from 6 to 7 d pupae were required2–4. Ilan et al. gave further evidence for a leucine tRNA which seemed to be controlling the translation of the mRNAs and the synthesis of which seemd to be in the control of juvenile homone3–7. But our own studies of Tenebrio, reported here, lead us to question this translational control model.