Expression analysis of GSK-3β in diapause pupal brains in the cotton bollworm, Helicoverpa armigera.

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 several signaling pathways. In this study, GSK-3β from the cotton bollworm, Helicoverpa armigera, was cloned using reverse transcription polymerase chain reaction and rapid amplification 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 protein has high identity to other known GSK-3β, as determined by Basic Local Alignment Search Tool analysis. Developmental expression of total GSK-3β and p-GSK-3β (Ser9) in diapause and non-diapause 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.