Daxx and histone deacetylase II associate with chromatin through an interaction with core histones and the chromatin-associated protein Dek.
Human Daxx is a protein that functions, in part, as a transcriptional co-repressor through its interaction with a growing number of nuclear, DNA-associated proteins. To determine the mechanism by which hDaxx represses transcription, we used conventional chromatography to isolate endogenous hDaxx. We determined that hDaxx has an apparent molecular weight of 360 kDa, which is consistent with the fact that multiple domains of hDaxx are required for transcriptional repression and suggests that hDaxx associates with multiple proteins. Using co-fractionation and co-immunoprecipitation we demonstrate that hDaxx associates with proteins that are critical for transcriptional repression, such as histone deacetylase II, constituents of chromatin such as core histones H2A, H2B, H3 and H4, and Dek, a chromatin-associated protein reported to change the topology of DNA in chromatin in vitro. We also demonstrate a requirement for the SPT domain and the first paired amphipathic helix of hDaxx for its association with histone deacetylase II and acetylated histone H4, respectively. Finally, we provide evidence suggesting that the association of hDaxx with chromatin-related proteins is dependent on the post-translational phosphorylation status of hDaxx. A working model for the repressive action of hDaxx through its association with chromatin related proteins is presented.
Department of Genetics, St. Jude Children's Research Hospital, 332 North Lauderdale, Memphis, TN 38105, USA.
Andrew D
AD
Hollenbach
Craig J
CJ
McPherson
Edwin J
EJ
Mientjes
Rekha
R
Iyengar
Gerard
G
Grosveld
D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D002843:Chromatin / Q000378:metabolism*; D002868:Chromosomal Proteins, Non-Histone; D056970:Co-Repressor Proteins; D004268:DNA-Binding Proteins / Q000378:metabolism; D005786:Gene Expression Regulation; D056464:Histone Deacetylase 2; D006655:Histone Deacetylases / Q000378:metabolism*; D006657:Histones / Q000378:metabolism*; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D051379:Mice; D008957:Models, Genetic; D018832:Molecular Chaperones; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D009690:Nucleic Acid Conformation; D009698:Nucleoproteins / Q000378:metabolism*; D015513:Oncogene Proteins / Q000378:metabolism*; D000075223:Poly-ADP-Ribose Binding Proteins; D011485:Protein Binding; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000378:metabolism*; D014158:Transcription, Genetic
D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; D056970:Co-Repressor Proteins; C106985:DAXX protein, human; D004268:DNA-Binding Proteins; C491473:Daxx protein, mouse; C084738:DEK protein, human; D006657:Histones; D047908:Intracellular Signaling Peptides and Proteins; D018832:Molecular Chaperones; D009687:Nuclear Proteins; D009698:Nucleoproteins; D015513:Oncogene Proteins; D000075223:Poly-ADP-Ribose Binding Proteins; D020033:Protein Isoforms; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; C533424:Hdac2 protein, mouse; D056464:Histone Deacetylase 2; D006655:Histone Deacetylases