The Borfl protein is encoded by an immediate-early gene of the bovine foamy virus （BFV） and plays a key role in the viral life cycle. Borfl is a DNA binding protein which can transactivate both the long terminal repeat （LTR） and the internal promoter （IP） of BFV by specifically binding to the transactivation responsive element （TRE）. To analyze the subcellular localization of Borfl during the BFV life cycle, this gene was cloned into a prokaryotic expression vector and expressed in a soluble form. After the purification and immunization, we raised the mouse anti-Borfl serum with a high titer based on ELISA results. Western blot analysis showed that the antiserum could specifically recognize the Borfl protein that was expressed in 293T cells. With this specific serum, we revealed the nuclear and cytoplasmic localization of Borfl in HeLa cells that was transfected with Borfl. Moreover, the immuno-fluorescence assay also showed that the localization of Borfl during the infection and transfection of BFV was identical.
Juan TAN Kai WU Rui CHANG Qi-min CHEN Yun-qi GENG Wen-tao QIAO
