Parallel changes in puffing activity and patterns of protein synthesis in salivary glands of Drosophila.

The changes in protein synthesis of salivary glands of Drosophila resulting from a brief exposure at 37 degrees have been analyzed on sodium dodecyl sulfate--acrylamide gels. In D. melanogaster and D. hydei this treatment induces nine and six new puffs, respectively, in the polytene chromosomes. After 20 min treatment seven new proteins are synthesized by the glands of D. melanogaster and six by those of D. hydei as detected by [35S]methionine labeling. Other agents, e.g., recovery from anaerobiosis, induce the same puffs and the same proteins. The extent of protein induction and the degree of puff induction are related to the severity of the temperature treatment. The new proteins are detected after 10 min treatmene at 37 degrees and their synthesis is inhibited by actinomycin D. Actinomycin D added 5 min after the start of temperature treatment has little effect on subsequent protein synthesis. The induced proteins are not tissue specific. Electrophoretic differences of two proteins exist between D. melanogaster and D. simulans, encouraging attempts to map the proteins' gene loci and to test directly whether or not the puffs code for them.