Functional activity of the BST2 gene in transfected CMK sublines. (A) The coding cDNA of BST2 gene was amplified by PCR and subcloned into a mammalian expression vector, pcDNA3. The BST2 construct was stably transfected into the DS AMkL cell line, CMK. Overexpression of BST2 in 2 of the stable clones was confirmed by real-time RT-PCR. (B) Protection of BST2 stable clones from ara-C-induced apoptosis by bone marrow stromal cells, HS-5, determined with annexin-FITC on an Epics-XL MCL flow cytometer, as described in “Materials and methods.” Error bars indicate standard error of 3 independent experiments. ^*Statistically significant difference (P < .005).