Protein synthesis in salivary glands of Drosophila hydei after experimental gene induction.

Several treatments, namely incubation at 37 degrees C, in the presence of arsenite, 2,4-dinitrophenol or vitamin B-6, or release from anaerobiosis induce the same set of puffs in the polythene chromosomes of salivary glands of Drosophila hydei. Analysis of changes in protein-synthetic patterns (as determined by radioautography of sodium dodecyl sulphate-gel electrophoretograms of extracts from [35S]methionine-labelled salivary glands) showed that concomitant with puff induction by these various treatments the same six strongly labelled polypeptide bands appeared. The amount of radioactive label in these peptides accounted for 25% of the total incorporation of [35S]methionine, except during incubation at 37 degrees C when it accounted for about 50%. The rate of synthesis of these peptides was maximal 1 h after the start of the puff-inducing treatment. The rate of decay of the rate of synthesis showed first-order kinetics both after removal of the puff-inducing stimulus or in the presence of actinomycin, with a half-life of approx. 4h.