Diapause is an adaptive response to adverse environmental conditions, but the molecular mechanisms are unclear. Some signaling molecules have been identified in the regulation of diapause. GSK-3β is an important signaling protein involved in sev- eral signaling pathways. In this study, GSK-3β from the cotton bollworm, Helicoverpa armigera, was cloned using reverse transcription polymerase chain reaction and rapid am- plification of complementary DNA （cDNA） ends techniques. Sequence analysis showed that the full-length cDNA was 1447 bp containing a 292 bp 5＇-untranslated region （UTR）, a 162 bp 3＇-UTR and a 993 bp open reading frame （ORF）. The deduced Har-GSK-3β pro- tein has high identity to other known GSK-3β, as determined by Basic Local Alignment Search Tool analysis. Developmental expression of total GSK-3/3 and p-GSK-3β （Ser9） in diapause and non-diapanse pupal brains was investigated by Western blotting. Results indicated that the activity of GSK-3β is down-regulated in diapause pupal brains, which is further confirmed by Western blotting after diapause break. These finding suggest that the down-regulation of Har-GSK-3β activity may be important for pupal diapause.
