cDNA cloning and recombinant expression of a proliferation inducing ligand (APRIL) from Père David's deer.

In the present study, the cDNA of Père David's deer APRIL (miAPRIL) was successfully amplified, and nucleotide sequence analysis showed that the open reading frame (ORF) of miAPRIL consists of 753 bases encoding 250-amino acids. Phylogenetic analysis exhibited high homology with the even-toed ungulates (artiodactyla). The extracellular soluble domain of the miAPRIL (misAPRIL) fragment was cloned into the expression vector pET43.1a and transformed into Escherichia coli BL21 (DE3) for recombinant expression. SDS-PAGE and western blotting analysis indicated that misAPRIL protein expression was successfully achieved. Indirect immunofluorescence staining demonstrated that misAPRIL has the ability to bind to the surface of Père David's deer lymphocytes. Flow cytometry analysis revealed that misAPRIL was able to enhance lymphocytes survival in a dose-dependent manner.