Elongin B is a subunit of the transcription factor B (SIII) complex, which activates elongation by mammalian RNA polymerase II by suppressing transient pausing of the polymerase at many sites within transcription units. Elongin is a heterotrimer composed of A, B, and C subunits. Elongin A functions as the transcriptionally active component of Elongin (SIII), while Elongin B and C are regulatory subunits [].Elongin B has been shown to form complex with Elongin C and VHL (von Hippel-Lindau, a tumour suppressor). This complex, known as the VBC complex, shows structural similarities with the SCF complex []. The VBC complex binds to hypoxia-inducible factor 1alpha (HIF-1alpha) via VHL and targets HIF-1alpha for ubiquitination [].
