HHV-8 replication is required for NF-κB induction in HUVECs. HUVECs were mock infected (mock), infected with HHV-8 or UV-inactivated HHV-8 (HHV-8 UV), or treated with TPA (20 ng/mL). At different times after infection, whole-cell extracts were prepared and assayed for NF-κB activation by EMSA. (A) Sections of fluorograms from native gels are shown. Position of NF-κB-DNA (NF-κB) and nonspecific protein-DNA (ns) complexes are indicated. (B) Results of RT-PCR amplification of the HHV-8 ORF50 gene using RNA extracted from mock-infected (mock), HHV-8–infected, or UV-inactivated HHV-8–infected cells. Positive control of ORF50 amplification (C+) and control for DNA contamination, performed by direct amplification of RNA without retrotranscription (RT−) are shown.