Three-dimensional organization of promyelocytic leukemia nuclear bodies

Abstract

SummaryPromyelocytic leukemia nuclear bodies (PML-NBs) are mobile subnuclear organelles formed by PML and Sp100 protein. They have been reported to have a role in transcription, DNA replication and repair, telomere lengthening, cell cycle control and tumor suppression. We have conducted high-resolution 4Pi fluorescence laser-scanning microscopy studies complemented with correlative electron microscopy and investigations of the accessibility of the PML-NB subcompartment. During interphase PML-NBs adopt a spherical organization characterized by the assembly of PML and Sp100 proteins into patches within a 50-to 100-nm-thick shell. This spherical shell of PML and Sp100 imposes little constraint to the exchange of components between the PML-NB interior and the nucleoplasm. Post-translational SUMO modifications, telomere repeats and heterochromatin protein 1 were found to localize in characteristic patterns with respect to PML and Sp100. From our findings, we derived a model that explains how the three-dimensional organization of PMLNBs serves to concentrate different biological activities while allowing for an efficient exchange of components.

PML induces compaction, TRF2 depletion and DNA damage signaling at telomeres and promotes their alternative lengthening

“…In line with a previous study (Potts and Yu, 2007), knockdown of these proteins reduced APB formation in our RNAi screen. The relevance of sumoylation of shelterin and PML-NB components for PML-NB and APB formation has been described in a number of previous studies (Brouwer et al, 2009;Chung et al, 2011;Hattersley et al, 2011;Lang et al, 2010;Potts and Yu, 2007;Yu et al, 2010). Here, we additionally found that MMS21 knockdown increased TRF2 binding to telomeres in APBs, whereas knockdown of the SUMO protease SENP6 resulted in a decrease.…”

“…2G). PML enrichment upon HP1γ recruitment could be due to SUMO-mediated interactions as discussed previously (Lang et al, 2010) or could occur through SP100 (Seeler et al, 1998), a known interaction partner of PML. Notably, PML enrichment was accompanied by the induction of repair-associated DNA synthesis, as concluded from the increased levels of the phosphorylated histone variant H2A.X (γH2A.X) and of incorporated 5-bromo-2'-deoxyuridine (BrdU) (Fig.…”

PML nuclear bodies: Assembly and oxidative stress-sensitive sumoylation

“…7,[25][26][27] Immunoelectron or high resolution confocal analyses indicate that the PML protein forms the outer shell, whereas partner proteins are concentrated in the inner core. 26,[28][29][30] The outer PML shell is associated with the nuclear matrix, a loosely defined, insoluble nuclear scaffold that is resistant to nuclease and high salt extraction and thought to support nuclear organization and compartmentalization. 31,32 Over the course of many years, a growing number of functionally distinct proteins and enzymes were shown to be recruited into PML NBs, notably p53 and many of its regulatory enzymes.…”

The SP100 component of ND10 enhances accumulation of PML and suppresses replication and the assembly of HSV replication compartments

“…ND10 structures form and reform in response to stress. They consist of an outer shell composed of PML, a set of constant proteins (e.g., CBP, Daxx, SP100 nuclear antigen), and various other proteins depending on the particular stress or function of the ND10 bodies (1)(2)(3)(4)(5)(6)(7). ND10 bodies have drawn attention recently, in large part because of increasing evidence suggesting that they sense and respond to infection (5,8).…”