The proviral DNA contains all of the signals necessary to support transcription of the viral genome mediated by the host cell RNA polymerase II. The viral long terminal repeat (LTR) binds a variety of cellular transcription factors, including the host cell encoded NFkappaB heterodimer 
For review see: 
- Nabel G, Baltimore D. 1987. An inducible transcription factor activates expression of human immunodeficiency virus in T cells. Nature 326: 711-713.
- Karn J, Stoltzfus CM. 2012. Transcriptional and Posttranscriptional Regulation of HIV-1 Gene Expression, in HIV From Biology to Prevention and Treatment, pp. 77 Cold Spring Harbor Laboratory Press, Cold Spring Harbor.