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The transcription coactivator CBP is a dynamic component of the promyelocytic leukemia nuclear body.

Boisvert FM, Kruhlak MJ, Box AK, Hendzel MJ, Bazett-Jones DP - J. Cell Biol. (2001)

Bottom Line: In cells where CBP does not normally accumulate in PML bodies, it can be induced to accumulate in PML bodies through overexpression of either CBP or Pml, but not Sp100.They possess the characteristics expected of proteins that would play a structural role in the integrity of these subnuclear domains.Our results are consistent with CBP being a dynamic component of PML bodies and that the steady-state level in these structures can be modulated by Pml.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell Biology and Anatomy, University of Calgary, Calgary, Alberta T2N 4N1, Canada.

ABSTRACT
The transcription coactivator and histone acetyltransferase CAMP response element-binding protein (CBP) has been demonstrated to accumulate in promyelocytic leukemia (PML) bodies. We show that this accumulation is cell type specific. In cells where CBP does not normally accumulate in PML bodies, it can be induced to accumulate in PML bodies through overexpression of either CBP or Pml, but not Sp100. Using fluorescence recovery after photobleaching, we demonstrate that CBP moves rapidly into and out of PML bodies. In contrast, Pml and Sp100 are relatively immobile in the nucleoplasm and within PML nuclear bodies. They possess the characteristics expected of proteins that would play a structural role in the integrity of these subnuclear domains. Our results are consistent with CBP being a dynamic component of PML bodies and that the steady-state level in these structures can be modulated by Pml.

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Localization of Pml and CBP by deconvolution immunofluorescence microscopy after exposure of these 293 cells to α-interferon (1,000 U/ml) for 72 h. Bar: (left panel) 5.5 μm; (right, panels 1–3) 1.38 μm.
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Figure 2: Localization of Pml and CBP by deconvolution immunofluorescence microscopy after exposure of these 293 cells to α-interferon (1,000 U/ml) for 72 h. Bar: (left panel) 5.5 μm; (right, panels 1–3) 1.38 μm.

Mentions: Overexpression of Pml protein leads to an accumulation of CBP in PML bodies in cells that do not otherwise show this localization. We wished to determine whether induction of Pml by α-interferon might also lead to an accumulation of CBP in PML bodies. As expected, after induction of 293 cells with α-interferon, the number of PML bodies increased by three- to fourfold and the total immunofluorescence signal increased approximately threefold (not shown), consistent with previous studies (Lavau et al. 1995). After 72 h of exposure to interferon, the CBP distribution changed significantly. Before induction of 293 cells, CBP is distributed in hundreds of small foci throughout the nucleoplasm. There is almost no overlap of these foci with PML bodies. However, after treatment larger foci appear, and many of these colocalize with PML bodies (Fig. 2, objects 1 and 2 in left panel). Other accumulations of CBP, however, are near but do not align precisely with PML bodies (Fig. 2, objects 2 and 3 in right panel). We do not know the basis for the accumulation of CBP into the larger foci that are not PML bodies upon interferon induction, but the accumulation of CBP in PML bodies mimics the accumulation seen when Pml levels are increased through transient overexpression.


The transcription coactivator CBP is a dynamic component of the promyelocytic leukemia nuclear body.

Boisvert FM, Kruhlak MJ, Box AK, Hendzel MJ, Bazett-Jones DP - J. Cell Biol. (2001)

Localization of Pml and CBP by deconvolution immunofluorescence microscopy after exposure of these 293 cells to α-interferon (1,000 U/ml) for 72 h. Bar: (left panel) 5.5 μm; (right, panels 1–3) 1.38 μm.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2198823&req=5

Figure 2: Localization of Pml and CBP by deconvolution immunofluorescence microscopy after exposure of these 293 cells to α-interferon (1,000 U/ml) for 72 h. Bar: (left panel) 5.5 μm; (right, panels 1–3) 1.38 μm.
Mentions: Overexpression of Pml protein leads to an accumulation of CBP in PML bodies in cells that do not otherwise show this localization. We wished to determine whether induction of Pml by α-interferon might also lead to an accumulation of CBP in PML bodies. As expected, after induction of 293 cells with α-interferon, the number of PML bodies increased by three- to fourfold and the total immunofluorescence signal increased approximately threefold (not shown), consistent with previous studies (Lavau et al. 1995). After 72 h of exposure to interferon, the CBP distribution changed significantly. Before induction of 293 cells, CBP is distributed in hundreds of small foci throughout the nucleoplasm. There is almost no overlap of these foci with PML bodies. However, after treatment larger foci appear, and many of these colocalize with PML bodies (Fig. 2, objects 1 and 2 in left panel). Other accumulations of CBP, however, are near but do not align precisely with PML bodies (Fig. 2, objects 2 and 3 in right panel). We do not know the basis for the accumulation of CBP into the larger foci that are not PML bodies upon interferon induction, but the accumulation of CBP in PML bodies mimics the accumulation seen when Pml levels are increased through transient overexpression.

Bottom Line: In cells where CBP does not normally accumulate in PML bodies, it can be induced to accumulate in PML bodies through overexpression of either CBP or Pml, but not Sp100.They possess the characteristics expected of proteins that would play a structural role in the integrity of these subnuclear domains.Our results are consistent with CBP being a dynamic component of PML bodies and that the steady-state level in these structures can be modulated by Pml.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell Biology and Anatomy, University of Calgary, Calgary, Alberta T2N 4N1, Canada.

ABSTRACT
The transcription coactivator and histone acetyltransferase CAMP response element-binding protein (CBP) has been demonstrated to accumulate in promyelocytic leukemia (PML) bodies. We show that this accumulation is cell type specific. In cells where CBP does not normally accumulate in PML bodies, it can be induced to accumulate in PML bodies through overexpression of either CBP or Pml, but not Sp100. Using fluorescence recovery after photobleaching, we demonstrate that CBP moves rapidly into and out of PML bodies. In contrast, Pml and Sp100 are relatively immobile in the nucleoplasm and within PML nuclear bodies. They possess the characteristics expected of proteins that would play a structural role in the integrity of these subnuclear domains. Our results are consistent with CBP being a dynamic component of PML bodies and that the steady-state level in these structures can be modulated by Pml.

Show MeSH
Related in: MedlinePlus