DIAPAUSE-SPECIFIC GENE-EXPRESSION IN PUPAE OF THE FLESH FLY SARCOPHAGA-CRASSIPALPIS

Several cDNAs isolated from brains of diapausing pupae of the flesh fl y, Sarcophaga crassipalpis, show expression patterns unique to diapaus e, To isolate such cDNAs a diapause pupal brain cDNA library was scree ned by using an elimination hybridization technique, and cDNAs that di d not hybridize with cDNA probes constructed from the RNA of nondiapau sing pupae were selected for further screening. The 95 clones that did not hybridize in the initial library screen were selected for further characterization. These clones were then screened against diapause an d nondiapause pupal poly(A)(+) Northern blots. The secondary screen id entified 4 diapause-up-regulated clones, 7 diapause-down-regulated clo nes, 8 clones expressed equally in both diapause and nondiapause, and 75 clones without detectable expression. The diapause-up-regulated and down-regulated clones were further characterized by partial DIVA sequ encing and identity searches by using GenBank. Identities between our cloned cDNAs and other genes included those linked to cell cycle progr ession, stress responses, and DNA repair processes. The results sugges t that insect diapause is not merely a shutdown of gene expression but is a unique, developmental pathway characterized by the expression of a novel set of genes.