Background : Several recent reports have connected protein methylation with differentiation. Furthermore, the BTG/TOB proteins have also been implicated in such control. BTG1 and 2 have been shown to interact with PRMT1 (predominant cellular arginine N-methyltransferase of type I).

DNA viruses such as herpes simplex virus type 1 (HSV-1) appear to start their replicative processes at specific nuclear domains known as ND10. In analyses to determine the minimum viral components needed for transcript accumulation at ND10, we find that a specific viral DNA sequence, OriS, and the viral immediateearly proteins ICP4 and ICP27 are sufficient for a reporter gene placed in cis to the OriS sequence to transcribe at ND10. A chromatin immunoprecipitation assay demonstrated expected critical intermediates in retaining the minimal genome at ND10 for the HSV-1 replication origin through direct or indirect binding to the host protein Daxx. Coimmunoprecipitation assays with antibodies to Daxx and ICP4, ICP27, and ICP8 showed that the respective proteins interact, possibly forming a complex. A potential complex between the origin, early viral DNA-binding protein ICP8 and Daxx did not result in transcription at ND10. Thus, the deposition of transcriptionally active HSV-1 genomes at ND10 is most likely a consequence of retention at ND10 through the interaction of viral genome-bound ICP4 and ICP27 with Daxx. Such a complex might be more likely immobilized at the outside of ND10 by the PML-interacting Daxx than at other nuclear sites.Most DNA viruses enter the nucleus by facilitated transport through the nuclear pore complex (49). Once inside the nucleus, some viral genomes make their way to nuclear domains called ND10, PML bodies, or PODs (18, 33). It is not clear whether viral genomes diffuse through the nuclear spaces or are deposited by an active mechanism at ND10. Apparently, only the few viral genomes arriving at this nuclear domain begin transcription and later, presumably at the same site, replication (20), suggesting a specifically advantageous environment for the virus at ND10. On the other hand, the dominant proteins of ND10 are interferon upregulated and have repressive properties (26, 51). Moreover, most DNA viruses encode an immediate-early (IE) protein that induces the degradation of ND10-associated proteins (12,18,22,32) and, in the absence of these viral proteins, replication is severely retarded (35, 46). These findings have led to the hypothesis that ND10 represent sites of a nuclear defense mechanism (34).ND10 are nuclear accumulations of various proteins, and PML is essential for their recruitment (19, 23, 52). These nuclear domains appear to function as nuclear depots, since several proteins, when increased in abundance by induced transcription or reduced turnover, accumulate at these sites (38). The capacity of the depots for protein recruitment is increased by the interferon upregulation of PML, Sp100, and Daxx (7, 8, 14-16, 19, 24, 45), and the protein recruitment is regulated by the sumofication of PML (19). The release of proteins from ND10 is regulated by the SENP-1 desumofication of PML and by p38 MAPK/ERK1/2 phosphorylation pathways, depending on the presence of an external signal such as hyperthermia or heavy metal exposure (37). The recruitment and segregation of undesirable compo...