Elongation factor component of the super elongation complex (SEC), a complex required to increase the catalytic rate of RNA polymerase II transcription by suppressing transient pausing by the polymerase at multiple sites along the DNA (PubMed:11689450). Elongation factor component of the little elongation complex (LEC), a complex required to regulate small nuclear RNA (snRNA) gene transcription by RNA polymerase II and III (PubMed:22195968, PubMed:23932780). Component of the super elongation complex (SEC), at least composed of Ell, Cdk9, cyclin-T (CycT), lilli and ear. Component of the little elongation complex, at least composed of Ell, Eaf, Ice1 and Ice2. Associates with RNA polymerase II. Localizes with RNA polymerase II at many transcriptionally active sites along polytene euchromatic chromosome arms and at developmental puff sites. Upon heat shock, relocalizes together with RNA polymerase II to selected heat shock puffs (PubMed:11689450). Associates to transcriptionally active chromatin at snRNA genes (PubMed:22195968). Expressed in salivary glands (at protein level). Belongs to the ELL/occludin family.