The human immunodeficiency virus transactivator Tat interacts with the RNA polymerase II holoenzyme.

AUTOR(ES)

Cujec, T P

RESUMO

The human immunodeficiency virus (HIV) encodes a transcriptional transactivator (Tat), which binds to an RNA hairpin called the transactivation response element (TAR) that is located downstream of the site of initiation of viral transcription. Tat stimulates the production of full-length viral transcripts by RNA polymerase II (pol II). In this study, we demonstrate that Tat coimmunoprecipitates with the pol II holoenzyme in cells and that it binds to the purified holoenzyme in vitro. Furthermore, Tat affinity chromatography purifies a holoenzyme from HeLa nuclear extracts which, upon addition of TBP and TFIIB, supports Tat transactivation in vitro, indicating that it contains all the cellular proteins required for the function of Tat. By demonstrating that Tat interacts with the holoenzyme in the absence of TAR, our data suggest a single-step assembly of Tat and the transcription complex on the long terminal repeat of HIV.

Documentos Relacionados

• Factors associated with the mammalian RNA polymerase II holoenzyme.
• CA150, a nuclear protein associated with the RNA polymerase II holoenzyme, is involved in Tat-activated human immunodeficiency virus type 1 transcription.
• Human immunodeficiency virus type 1 and 2 Tat proteins specifically interact with RNA polymerase II.
• Walleye Dermal Sarcoma Virus Cyclin Interacts with Components of the Mediator Complex and the RNA Polymerase II Holoenzyme
• Trans-activation by human immunodeficiency virus Tat protein requires the C-terminal domain of RNA polymerase II.