Abstract:  β-tubulin is involved in a variety of functions, such as the development of insect, signal pathway and pesticide resistance. Total RNA was isolated from the 3rd instar larvae of Agrotis ypsilon (Rottemberg), and the full-length cDNA was cloned by RT-PCR and RACE, named as AgTubB (GenBank accession number: JN029962). The mRNA levels were examined in different developmental stages and various organs. β-tubule cDNA sequence, 1 724 bp in length, contains an open reading frame of 1 347 bp, encoding 448 amino acids. The predicted molecular weight of the amino acid is approximately 50.30 kD with an isoelectric point of 4.81. The cloned β-tubulin gene shares the highest identity with that of Helicoverpa armigera (amino acid sequence identity 99.55%), and its amino acid sequences have about 90%-99% identity with other insect tubulins compared. The mRNA levels of β-tubulin gene were constant at different developmental stages and in various organs. The molecular cloning of β-tubulin gene is important for further study on the function of this gene and screening of β-tubulin inhibitors.

Key words: Agrotis ypsilon, cDNA cloning, β-tubulin, sequence analysis, protein structure, gene expression