Purified anti-TIF1beta (KAP-1, TRIM28)

TIFbeta (transcription intermediary factor 1-beta) is an 88 kD member of the tripartite motif family. This protein contains three zinc binding domains, a RING domain, a B-box type 1 and type 2 domain, and a coiled-coil region. TIFbeta is found in the nucleus and associates with specific chromatin regions. This protein forms a complex with KRAB-domain transcription factors and recruits setdbl to histone 3 to increase KRAB-mediated transcriptional repression. TIF1beta has been reported to interact with setdbl and cbx3 proteins. Studies using knockout mice reveal the important function of TIF1beta in regulating genomic imprinting, T cell activation, and T cell tolerance.