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Peter Lorenz, Dirk Koczan, Hans-Jürgen Thiesen
Transcriptional Repression Mediated by the KRAB Domain of the Human C2H2 Zinc Finger Protein Kox1/ZNF10 Does Not Require Histone Deacetylation
The KRAB domain of human Kox1, a member of the KRAB C2H2 zinc finger family, confers strong transcriptional repressor activities even to remote promoter positions. Here, HDAC inhibitors were used to demonstrate that histone deacetylation is not required for mediating transcriptional repression of KRAB zinc finger proteins. Two reporter systems with either stably integrated or transiently transfected templates, both under control of strong viral promoters, were analyzed. Under all circumstances, HDAC inhibition did not alter the repression potential of the KRAB domain. In case of the stably integrated luciferase reporter gene system, neither expression levels of the KRAB fusion protein nor complex formation with its putative corepressor TIF1? were significantly changed. Furthermore, the TIF1?/KRAB complex was devoid of mSin3A and HDAC1. In the transient transfection system, the transcriptional repression induced by TIF1? and HP1? was not diminished by HDAC inhibitors, whereas the repressory activity of TIF1? was significantly affected. Thus, KRAB, TIF1? and HP1? are likely to be functionally linked. In conclusion, HDAC activity is not essential for the strong transcriptional repressor activity mediated by the KRAB domain of Kox1 in particular and, presumably, by KRAB domains in general. This feature might be helpful in identifying and characterizing target genes under the control of KRAB zinc finger proteins.
Biological Chemistry, Walter de Gruyter
Print ISSN: 1431-6730
Volume: 382, 04/2001
Pages: 637 - 644