Limits...
A novel chromatin tether domain controls topoisomerase IIα dynamics and mitotic chromosome formation.

Lane AB, Giménez-Abián JF, Clarke DJ - J. Cell Biol. (2013)

Bottom Line: Here we describe a critical mechanism of chromatin recruitment and exchange that relies on a novel chromatin tether (ChT) domain and mediates interaction with histone H3 and DNA.We show that the ChT domain controls the residence time of Topo IIα on chromatin in mitosis and is necessary for the formation of mitotic chromosomes.Our data suggest that the dynamics of Topo IIα on chromosomes are important for successful mitosis and implicate histone tail posttranslational modifications in regulating Topo IIα.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN 55455.

ABSTRACT
DNA topoisomerase IIα (Topo IIα) is the target of an important class of anticancer drugs, but tumor cells can become resistant by reducing the association of the enzyme with chromosomes. Here we describe a critical mechanism of chromatin recruitment and exchange that relies on a novel chromatin tether (ChT) domain and mediates interaction with histone H3 and DNA. We show that the ChT domain controls the residence time of Topo IIα on chromatin in mitosis and is necessary for the formation of mitotic chromosomes. Our data suggest that the dynamics of Topo IIα on chromosomes are important for successful mitosis and implicate histone tail posttranslational modifications in regulating Topo IIα.

Show MeSH

Related in: MedlinePlus

Immunolocalization of histone H3 isoforms in mitotic M. muntjak chromosomes.M. muntjak cells stained with antibodies against H3K27me1 (A) or H3K27me3 (B), or costained with H3K27me3 and H3S28p (C and D). H3K27me1 and H3K27me3 are distributed throughout chromosome arms, whereas H3S28p is more peripheral. Flattened z stacks are shown. DAPI, DNA stain. Bars, 10 µm. Images on the right show enlarged segments of the boxed regions (bars, 1.25 µm).
© Copyright Policy - openaccess
Related In: Results  -  Collection

License 1 - License 2
getmorefigures.php?uid=PMC3824022&req=5

fig5: Immunolocalization of histone H3 isoforms in mitotic M. muntjak chromosomes.M. muntjak cells stained with antibodies against H3K27me1 (A) or H3K27me3 (B), or costained with H3K27me3 and H3S28p (C and D). H3K27me1 and H3K27me3 are distributed throughout chromosome arms, whereas H3S28p is more peripheral. Flattened z stacks are shown. DAPI, DNA stain. Bars, 10 µm. Images on the right show enlarged segments of the boxed regions (bars, 1.25 µm).

Mentions: If Topo IIα binds preferentially to certain histone H3 isoforms in vivo, then one possibility is that the localization patterns of such isoforms and of Topo IIα are related. Of particular interest is that phosphorylation of Ser 28 is associated with mitotic chromosomes (Goto et al., 2002), and it was therefore counterintuitive that this modification inhibits the interaction of H3 and Topo IIα CTR in vitro (Fig. 4). To investigate this we immunostained the large mitotic chromosomes of M. muntjak using antibodies that have specificity for K27me1, K27me3, or S28p. Both K27 methylation-specific antibodies stained the entire width of mitotic chromosomes, with K27me1 localizing with a more punctate pattern than K27me3 (Fig. 5, A and B). In contrast, S28p antibodies stained the periphery of chromosomes intensely, with weak staining within the perimeter of each chromosome. To ensure that this pattern was not caused by poor penetration of antibody into chromosomes, we costained with antibodies against K27me3 and S28p. This revealed a clear contrast in localization patterns, where S28p was peripheral and K27me3 was present throughout the width of chromosome arms (Fig. 5, C and D).


A novel chromatin tether domain controls topoisomerase IIα dynamics and mitotic chromosome formation.

Lane AB, Giménez-Abián JF, Clarke DJ - J. Cell Biol. (2013)

Immunolocalization of histone H3 isoforms in mitotic M. muntjak chromosomes.M. muntjak cells stained with antibodies against H3K27me1 (A) or H3K27me3 (B), or costained with H3K27me3 and H3S28p (C and D). H3K27me1 and H3K27me3 are distributed throughout chromosome arms, whereas H3S28p is more peripheral. Flattened z stacks are shown. DAPI, DNA stain. Bars, 10 µm. Images on the right show enlarged segments of the boxed regions (bars, 1.25 µm).
© Copyright Policy - openaccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3824022&req=5

fig5: Immunolocalization of histone H3 isoforms in mitotic M. muntjak chromosomes.M. muntjak cells stained with antibodies against H3K27me1 (A) or H3K27me3 (B), or costained with H3K27me3 and H3S28p (C and D). H3K27me1 and H3K27me3 are distributed throughout chromosome arms, whereas H3S28p is more peripheral. Flattened z stacks are shown. DAPI, DNA stain. Bars, 10 µm. Images on the right show enlarged segments of the boxed regions (bars, 1.25 µm).
Mentions: If Topo IIα binds preferentially to certain histone H3 isoforms in vivo, then one possibility is that the localization patterns of such isoforms and of Topo IIα are related. Of particular interest is that phosphorylation of Ser 28 is associated with mitotic chromosomes (Goto et al., 2002), and it was therefore counterintuitive that this modification inhibits the interaction of H3 and Topo IIα CTR in vitro (Fig. 4). To investigate this we immunostained the large mitotic chromosomes of M. muntjak using antibodies that have specificity for K27me1, K27me3, or S28p. Both K27 methylation-specific antibodies stained the entire width of mitotic chromosomes, with K27me1 localizing with a more punctate pattern than K27me3 (Fig. 5, A and B). In contrast, S28p antibodies stained the periphery of chromosomes intensely, with weak staining within the perimeter of each chromosome. To ensure that this pattern was not caused by poor penetration of antibody into chromosomes, we costained with antibodies against K27me3 and S28p. This revealed a clear contrast in localization patterns, where S28p was peripheral and K27me3 was present throughout the width of chromosome arms (Fig. 5, C and D).

Bottom Line: Here we describe a critical mechanism of chromatin recruitment and exchange that relies on a novel chromatin tether (ChT) domain and mediates interaction with histone H3 and DNA.We show that the ChT domain controls the residence time of Topo IIα on chromatin in mitosis and is necessary for the formation of mitotic chromosomes.Our data suggest that the dynamics of Topo IIα on chromosomes are important for successful mitosis and implicate histone tail posttranslational modifications in regulating Topo IIα.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN 55455.

ABSTRACT
DNA topoisomerase IIα (Topo IIα) is the target of an important class of anticancer drugs, but tumor cells can become resistant by reducing the association of the enzyme with chromosomes. Here we describe a critical mechanism of chromatin recruitment and exchange that relies on a novel chromatin tether (ChT) domain and mediates interaction with histone H3 and DNA. We show that the ChT domain controls the residence time of Topo IIα on chromatin in mitosis and is necessary for the formation of mitotic chromosomes. Our data suggest that the dynamics of Topo IIα on chromosomes are important for successful mitosis and implicate histone tail posttranslational modifications in regulating Topo IIα.

Show MeSH
Related in: MedlinePlus