This family of proteins represents the C-terminus of subunit 5 of the integrator complex involved in snRNA transcription and processing [1].

1: Integrator, a multiprotein mediator of small nuclear RNA processing, associates with the C-terminal repeat of RNA polymerase II. Baillat D, Hakimi MA, Naar AM, Shilatifard A, Cooch N, Shiekhattar R; Cell. 2005;123:265-276. PMID:16239144