Abstract: 【Aim】 Wnt1 is a key component of Wnt/β-catenin signaling pathway. The objective of this research was to clone the Wnt1 cDNA from  Helicoverpa armigera , to prepare the polyclonal antibody against Wnt1 and to investigate the Wnt1 protein levels in the brain of diapausing and non-diapausing pupae by Western blot. 【Methods】 Wnt1 gene was cloned by RACE from  H. armigera . Eukaryotic expression vector of Har-Wnt1 was constructed to study its subcellular localization. Prokaryotic expression vector was constructed and the recombinant protein was expressed in  Escherichia coli  BL21 (DE3). After being purified, the recombinant protein was used to immune New Zealand rabbit. The antibody titer was determined by ELISA. Western blot was used to investigate the Wnt1 protein levels in the brain of  H. armigera  pupae. 【Results】 Har-Wnt1 cDNA was cloned successfully from  H. armigera  (GenBank accession number: KJ206240). Har-Wnt1 was found to be exclusively in cytoplasm. After immunizing New Zealand rabbit by recombinant protein, we obtained the antibody against Har-Wnt1 and the titer was estimated as high as 1:625 000 dilution detected by ELISA. The expression levels of Har-Wnt1 were significantly higher in the brain of non-diapausing pupae than in the brain of diapausing pupae. 【Conclusion】 High titer antibody against Har-Wnt1 was obtained. Our results suggest that the Wnt/β-catenin pathway may be activated in non-diapausing pupae and down-regulated in diapausing pupae. This study lays a foundation for further investigating the function of Wnt/β-catenin in the diapause of H. armigera.

Key words: Helicoverpa armigera , Wnt1, diapause, protein purification, polyclonal antibody