Claim: The Sill complex is comprised of elongins A/A2, B and C which activates elongation by RNA polymerase II; elongin B is the subunit of transcription factor B Sill complex; and elongin A functions as the transcriptionally active component of the Sill complex (whereas elongins B and C are regulatory subunits).
Evidence: This gene encodes the protein elongin C, which is a subunit of the transcription factor B (SIII) complex.