Abstract: Ubiquitin plays a very important role in regulating non-lysosomal ATP-dependent protein degradation. The coding sequence of Haritalodes derogata (Fabricius) ubiquitin gene was cloned and determined (GenBank accession no. EU580145). The opening reading frame (ORF) is 228 bp in length, encoding 76 amino acids with the molecular weight of 8.53 kD and theoretical isoelectric point of 5.83. Multiple sequence alignment indicated that H. derogata ubiquitin shared more than 93% identity with those of other ten insect species at the amino acid level, indicating high homology among them. Phylogenetic tree indicated that H. derogate has close relationship with Spodoptera litura (Fabricius). The theoretical three-dimensional structure of this gene was displayed by homology modeling. Using pET-32a (+) as a fused expression vector, a recombinant plasmid pET-32a-ub containing the coding sequence of H. derogata ubiquitin gene was constructed. Western blotting indicated that the H. derogata ubiquitin gene was expressed successfully in the BL21 (DE3) strain of Escherichia coli induced with IPTG. The results may serve as basis for further studying the function of ubiquitin gene in this insect.

Key words: Haritalodes derogata, ubiquitin, gene cloning, gene sequence analysis, prokaryotic expression