Abstract: As one of the important internal controls, Β-actin plays an crucial role in maintaining cell structure, cell movement, and cell division of physiological activity. It is one of the widely used internal controls in the detection of gene transcription and protein level. In this study, Β-actin gene was cloned from cotton bollworm. Bioinformatics analysis showed that the open reading frame of Β-actin was 1 131 bp, encoding 376 amino acids, the theoretical molecular weight was 41.77 kD, and isoelectric point was 5.16. The similarity of amino acid between the Β-actin of cotton bollworm and one of other species was 98%-99%, while 99% similarity with Bombyx mori. Analysis of Β-actin antigenic determinant sites from cotton bollworm and Mus musculus indicated that their homology was 70.63%. Concurrently, Β-actin protein from prokaryotic expression of the gene was purified, and Western blot analysis showed that the expression was correct. The purified protein was used to immunize ICR mouse 4 times, the titer of mouse antiserum Β-actin reached 388 800 by ELISA assay. Moreover, the antiserum was able to specifically bind with the total protein of the cotton bollworm.

Key words: Helicoverpa armigera, Β, -actin, cloning, prokaryotic expression, polyclonal antibody