Strategy for cloning NF-κB activating molecules. A) A retroviral cDNA library from an ATL cell line is transduced to a reporter cell line expressing EGFP and bsr in response to NF-κB activation. Blasticidin-resistant and EGFP expressing cell clones are expanded and cDNA clones are obtained by PCR using the retrovirus vector specific primers. B) Visualization of NF-κB activation in reporter cells. Reporter cells were stimulated with TNF-α for 48 hours and tested for the expression of EGFP by FACS analysis.