This gene encodes transcription regulatory protein and a cell-cycle. The encoded protein interacts with the cell cycle inhibitor cyclin-dependent kinase 4 inhibitor B and may function as a negative regulator of G(1)/S phase progression. This protein interacts with phosphorylated C-terminal heptapeptide repeat domain (CTD) of the largest RNA polymerase II subunit POLR2A and participates in dephosphorylation of the CTD by RPAP2. May act as a negative regulator of cyclin-D1 (CCND1) and cyclin-E (CCNE1) in the cell cycle. This protein also forms homo- and heterodimer with the protein, regulation of nuclear pre-mRNA domain-containing protein 1B, to form a scaffold that interacts with the C-terminal domain of RNA polymerase II subunit B1 and regulates several aspects of transcription. Alternate splicing results in multiple transcript variants. A pseudogene of this gene is found on chromosome 16.