Zinc finger protein 140
negative regulation of transcription by RNA polymerase II
Repression of transcriptional activity by heterologous KRAB domains present in zinc finger proteins.
We report the characterization of three novel members of the KRAB-domain containing C2-H2 zinc finger family (ZNF133, 136 and 140). KRAB (Krüppel-associated box) is an evolutionarily conserved protein domain found N-terminally with respect to the zinc finger repeats that encodes the DNA binding domain. ZNF133 and ZNF140 have both the KRAB A- and KRAB B-boxes present at their N-terminus, whereas ZNF136 contains only the KRAB A-box. We have previously demonstrated that the KRAB domains derived from ZNF133 and ZNF140 are potent transcriptional repression domains [Margolin et al. (1994) Proc. Natl. Acad. Sci. USA 91, 4509-4513]. The KRAB domain from ZNF136, containing only subdomain A, is a considerable weaker suppression domain; however, when fused to the heterologous KRAB B subdomain of ZNF10 (KOX1) the two subdomains from a KRAB domain which induces repression as potently as previously reported KRAB domains.