This gene encodes a protein that belongs to a novel class of zinc finger proteins. The encoded protein functions as a transcriptional co-regulator, and as an E3 ubiquitin ligase that promotes the ubiquitination and proteasomal degradation of target proteins. The protein encoded by this gene is thought to regulate RNA polymerase II-catalyzed transcription. Substrates for this protein's E3 ubiquitin ligase activity include the capsid protein of the West Nile virus and the catalytic subunit of the telomerase ribonucleoprotein. This protein controls cell cycle arrest and apoptosis by regulating p21, a cell cycle regulator, and the tumor suppressor protein p53. Pseudogenes of this gene are present on chromosomes 1, 3, 9, 12 and 20, and on the X chromosome. Alternative splicing results in multiple transcript variants encoding different isoforms. [provided by RefSeq, Apr 2014].