Small Hsp27 Research Articles

Ecdysterone induces the transcription of four heat-shock genes in Drosophila S3 cells and imaginal discs

Ecdysterone stimulates a 2- to 15-fold increase in the synthesis of four small heat-shock proteins (hsp) in Drosophila line S3 cells. This is accompanied by a rapid and coincident increase in the abundance of small hsp transcripts. A parallel in vivo situation is now described in imaginal discs isolated from pupariating larvae. In neither system are the high-molecular-weight heat-shock proteins, or their RNAs, induced by hormone. Nor does induction occur in variant cell lines which have acquired resistance to ecdysterone. Other genes within or contiguous to the small hsp cluster are not induced by either ecdysterone or high temperature. Induction by ecdysterone appears to be a primary hormone response.