Cycles of protein synthesis during pupal diapause in the flesh fly, Sarcophaga crassipalpis

Abstract Protein synthesis is cyclic during pupal diapause in Sarcophaga crassipalpis . These cycles are in phase with infradian MO 2 cycles, which have a periodicity of about 4 days at 25°C. Mean incorporation of [ 35 S]methionine by diapausing pupae was 5.4% during the 2 days of highest MO 2 but dropped to 1.7% during the 2 days of low MO 2 . Diapausing pupae treated with a juvenile hormone analog prior to pupariation had a constant high MO 2 similar to peak values observed in untreated pupae, and such pupae consistently incorporated [ 35 S]methionine at a high rate (7.7%). [ 35 S]Methionine incorporation by nondiapausing pupae and pharate adults was eightfold higher than the peak rates observed during diapause. Autoradiography of in vivo labeled proteins indicated quantitative and qualitative changes in the synthesis of proteins by diapausing pupae during different phases of the MO 2 cycle. Brains from diapausing pupae labeled in vitro showed higher incorporation at the peak of the MO 2 cycle than at the nadir of the cycle, but no such differences were detected for integument, fat body, or fat body supernatant. Theses differences in tissue response indicate that control of protein synthesis during diapause is not cell autonomous, but is a function of the metabolism of the intact organism.