Cloning and sequence analysis of the Harmonia axyridis(Coleoptera: Coccinellinae) catalase gene
Author of the article:TANG Bin1, 2** SHI Zuo-Kun1 GUO Hong-Shuang1 WANG Su2 WANG Shi-Gui1 ZHANG Fan2***
Author's Workplace:1. Hangzhou Key Laboratory of Animal Adaptation and Evolution, Hangzhou Normal University, Hangzhou 310036, China;2. Institute of Plant and Environment Protection, Beijing Academy of Agriculture and Forestry Sciences, Beijing 100097, China
Key Words:Harmonia axyridis, catalase, gene cloning, sequence analysis
Abstract: [Objectives] To clone the full length cDNA sequence of the catalase gene from Harmonia axyridis, which codes for a kind of important protective insect enzyme, and analyze its basic characteristics. [Methods] Catalase (CAT) from Harmonia axyridis was cloned using homological cloning and anchored PCR, and the sequence analyzed using bioinformatic methods. [Results] The full length of the HaraxCAT cDNA sequence is 1 781 bp (GenBank accession number KC991026), which contains a 3′ untranslated region of 110 bp and a 5′ untranslated region of 45 bp. HaraxCAT cDNA contains an open reading frame of 1 626 bp, encoding a protein of 541 amino acids residues with a calculated molecular mass of 61.55 ku and pI of 8.33. It has three potential N-glycosylation sites, but no signal peptide, putative cleavage sites or transmembrane domain. HaraxCAT, including a proximal active site signature of FDRERIPERVVHAKGAGA which encodes about 18 amino acids, also includes a proximal heme ligand signature of RIFSYGDTH. Blast analysis indicated that insect CAT proteins are very conservative; HaraxCAT has > 65% similarity to that of other insects. HaraxCAT had 75.25% similarity with the corresponding sequence of Tribolium castaneum, and phylogenetic analysis shows that it is most closely related to T. castaneum and Protaetia brevitarsis. [Conclusion] Sequence analysis of the catalase gene from H. axyridis confirms that insect CAT protein are very conservative.