The PRH/Hex repressor protein causes nuclear retention of Groucho/TLE co-repressors.
The PRH (proline-rich homeodomain) [also known as Hex (haematopoietically expressed homeobox)] protein is a transcription factor that functions as an important regulator of vertebrate development and many other processes in the adult including haematopoiesis. The Groucho/TLE (transducin-like enhancer) family of co-repressor proteins also regulate development and modulate the activity of many DNA-binding transcription factors during a range of diverse cellular processes including haematopoiesis. We have shown previously that PRH is a repressor of transcription in haematopoietic cells and that an Eh-1 (Engrailed homology) motif present within the N-terminal transcription repression domain of PRH mediates binding to Groucho/TLE proteins and enables co-repression. In the present study we demonstrate that PRH regulates the nuclear retention of TLE proteins during cellular fractionation. We show that transcriptional repression and the nuclear retention of TLE proteins requires PRH to bind to both TLE and DNA. In addition, we characterize a trans-dominant-negative PRH protein that inhibits wild-type PRH activity by sequestering TLE proteins to specific subnuclear domains. These results demonstrate that transcriptional repression by PRH is dependent on TLE availability and suggest that subnuclear localization of TLE plays an important role in transcriptional repression by PRH.
Desjobert
Cecile
C
Department of Biochemistry, Medical School, University of Bristol, University Walk, Bristol BS81TD, UK.
Noy
Peter
P
Swingler
Tracey
T
Williams
Hannah
H
Gaston
Kevin
K
Jayaraman
Padma-Sheela
PS
D015153:Blotting, Western; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000378:metabolism*; D056970:Co-Repressor Proteins; D004247:DNA / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay; D005455:Fluorescent Antibody Technique; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D047468:Immunoprecipitation; D009154:Mutation; D011485:Protein Binding; D012097:Repressor Proteins / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
D056970:Co-Repressor Proteins; C078492:HHEX protein, human; D018398:Homeodomain Proteins; D012097:Repressor Proteins; C499043:TLE1 protein, human; D014157:Transcription Factors; D004247:DNA