Fig. 7. A model of hDaxx-mediated transcriptional repression. The post-translational modification status of the SPT domain of hDaxx regulates the interaction of hDaxx with transcription factors such as Pax3 (Hollenbach et al., 1999) and ETS-1 (Li et al., 2000b). By interacting with transcription factors, hDaxx is present at sites of active transcription and is capable of associating with acetylated core histones present in nucleosomes and the chromatin-associated protein Dek. As a consequence of the association of histone deacetylases with hDaxx, the histone tails in nucleosomes in the proximity of the site of active transcription are deacetylated, leading to an inactive chromatin structure (depicted as nucleosomes close together) and transcriptional repression. Aside from the acetylation state of the histone tails our model cannot specify the exact order in which the components are assembled at the active site of transcription nor can it specify at which step repression and dissociation of factors occurs. For simplicity we have illustrated Dek only on the nucleosomes closest to the transcription factor.