Table 2.

Tax oncoprotein activities

Transcriptional activities

Serum-response factor

cAMP-response factor–activation of viral promoter

Nuclear factor κB–activation of cytokines, anti-apoptosis genes, cell proliferation genes, and angiogenesis

Posttranscriptional activities

Proliferation–inhibition of p16 cell cycle inhibitor, activation of cyclin-dependent kinase 4 and cyclin 2

Apoptosis–inactivation of p53

Genetic instability defect in G2/M checkpoint caused by binding mitotic arrest defect 1 protein, Cdc20 anaphase-promoting complex, and checkpoint kinases Chk1 and 2