Zhang, Z., Klatt, A., Henderson, A.J., and Gilmour, D.S.
Notes: These authors showed that the termination factor Pcf11 negatively regulates expression of the HIV provirus by causing premature termination RNA pol II-mediated transcription elongation. ChIP assays revealed an association between Pcf11 and the HIV promoter region, and siRNA depletion of Pcf11 caused an increase in viral replication. Transcription in Pcf11-depleted nuclear extracts was shown to be insensitive to 6-dichloro-beta-D-ribofuranosylbenzimidazole (DRB), which is known to cause premature termination. Addition of purified Pcf11 back to the depleted nuclear extracts restored DRB sensitivity. The authors concluded that since HIV expression increases when Pcf11 is depleted, premature termination mediated by Pcf11 appears to play a role in maintaining transcriptional latency of the provirus. (3709)