Gene cloning of human PD--L2 gene and its expression in {\sl Escherichia coli}

Objective To clone the human PD-L2 gene and to construct a prokaryotic expression vector for the extracellular domain of PD-L2. Methods The cDNA of human PD-L2 gene was cloned from the total RNA of activated human peripheral blood mononuclear cells by RT-PCR. The prokaryotic expression vector for the extracellular domain of PD-L2 was constructed and its expression in Escherichia coli (E. coli) was determined. Results The full-length coding sequence of PD-L2 gene was cloned and confirmed by DNA sequencing, which was identical to the published gene. The prokaryotic expression vector for the extracellular domain of PD-L2 was then constructed. The recombinant protein was expressed in E. coli after the IPTG induction and identified by Western blotting. The recombinant protein had a molecular weight of 22 000, which was consistent with theoretical calculation. Conclusion The gene of PD-L2 is successfully cloned and the extracellular domain protein of the PD-L2 is expressed in E. coli, which provides a basis for the further study of the function of PD-L2.