Abstract: Myosin light chain 2 (MLC2) plays an important role in biological motility. Myosin light chain 2 gene was cloned from Bactrocera dorsalis and named as BdorMLC2. The open reading frame of BdorMLC2 is 669 bp in length encoding 222 amino acid residues. On-line SMART analysis revealed that BdorMLC2 has two EFh functional domains that can bind Ca²⁺, and belongs to one of the members of the troponin C superfamily. Homology analysis of amino acid sequence showed that BdorMLC2 has very high similarity with MLC from other insects and shares 93.2% identity with the MLC sequence from Drosophila melanogaster. Tissue expression analysis revealed that BdorMLC2 transcript was observed clearly in thorax of male B. dorsalis, and highly expressed in head (antennae removed), foreleg, middle legs, hind legs and wings. The temporal expression pattern further indicated that BdorMLC2 was expressed in different developmental stage. The highest expression level was found in newly-emerged adult compared to other developmental stages. The results suggest that BdorMLC2 might be closely related to muscle contraction of B. dorsalis. This study provides a basis for further researching the function of BdorMLC2.

Key words: Bactrocera dorsalis, myosin light chain 2, gene cloning, expression pattern analysis, real-time PCR