EFFECTS OF 20-HYDROXYECDYSONE ON PROTEIN-SYNTHESIS IN THE EPITHELIAL-CELL LINE FROM CHIRONOMUS-TENTANS

In the epithelial cell line of Chironomus tentans growth ceases after addition of 20-hydroxyecdysone. Under the influence of moulting hormon e the protein pattern changes as shown by 2-dimensional electrophoresi s and silver staining. Incorporation of S-35-labelled methionine revea ls qualitative and quantitative changes in the homogenate from the cel ls and in the proteins secreted into the medium. RNA from cells treate d with 20-OH-ecdysone for various times either permanently or with pul ses of moulting hormones was expressed in a reticulocyte in vitro tran slation system. Qualitative changes in the in vitro translated product s were first observed after 75 min and continue until day 4 after horm one treatment. A complex pattern of permanent and transient induction and repression of different transcripts is obtained.