open access

Vol 43, No 3 (2005)
ORIGINAL PAPERS
Published online: 2011-08-22
Submitted: 2011-12-19
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Rumex acetosa Y chromosomes: constitutive or facultative heterochromatin?

Magdalena Mosiołek, Paweł Pasierbek, Janusz Malarz, Maria Moś, Andrzej J. Joachimiak
Folia Histochem Cytobiol 2005;43(3):161-167.

open access

Vol 43, No 3 (2005)
ORIGINAL PAPERS
Published online: 2011-08-22
Submitted: 2011-12-19

Abstract

Condensed Y chromosomes in Rumex acetosa L. root-tip nuclei were studied using 5-azaC treatment and immunohistochemical detection of methylated histones. Although Y chromosomes were decondensed within root meristem in vivo, they became condensed and heteropycnotic in roots cultured in vitro. 5-azacytidine (5-azaC) treatment of cultured roots caused transitional dispersion of their Y chromosome bodies, but 7 days after removal of the drug from the culture medium, Y heterochromatin recondensed and again became visible. The response of Rumex sex chromatin to 5-azaC was compared with that of condensed segments of pericentromeric heterochromatin in Rhoeo spathacea (Sw.) Stearn roots. It was shown that Rhoeo chromocentres, composed of AT-rich constitutive heterochromatin, did not undergo decondensation after 5-azaC treatment. The Y-bodies observed within male nuclei of R. acetosa were globally enriched with H3 histone, demethylated at lysine 4 and methylated at lysine 9. This is the first report of histone tail-modification in condensed sex chromatin in plants. Our results suggest that the interphase condensation of Y chromosomes in Rumex is facultative rather than constitutive. Furthermore, the observed response of Y-bodies to 5-azaC may result indirectly from demethylation and the subsequent altered expression of unknown genes controlling tissue-specific Y-inactivation as opposed to the global demethylation of Y-chromosome DNA.

Abstract

Condensed Y chromosomes in Rumex acetosa L. root-tip nuclei were studied using 5-azaC treatment and immunohistochemical detection of methylated histones. Although Y chromosomes were decondensed within root meristem in vivo, they became condensed and heteropycnotic in roots cultured in vitro. 5-azacytidine (5-azaC) treatment of cultured roots caused transitional dispersion of their Y chromosome bodies, but 7 days after removal of the drug from the culture medium, Y heterochromatin recondensed and again became visible. The response of Rumex sex chromatin to 5-azaC was compared with that of condensed segments of pericentromeric heterochromatin in Rhoeo spathacea (Sw.) Stearn roots. It was shown that Rhoeo chromocentres, composed of AT-rich constitutive heterochromatin, did not undergo decondensation after 5-azaC treatment. The Y-bodies observed within male nuclei of R. acetosa were globally enriched with H3 histone, demethylated at lysine 4 and methylated at lysine 9. This is the first report of histone tail-modification in condensed sex chromatin in plants. Our results suggest that the interphase condensation of Y chromosomes in Rumex is facultative rather than constitutive. Furthermore, the observed response of Y-bodies to 5-azaC may result indirectly from demethylation and the subsequent altered expression of unknown genes controlling tissue-specific Y-inactivation as opposed to the global demethylation of Y-chromosome DNA.
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Keywords

Y chromosomes; Heterochromatin; Methylation; Histone H3; Rumex

About this article
Title

Rumex acetosa Y chromosomes: constitutive or facultative heterochromatin?

Journal

Folia Histochemica et Cytobiologica

Issue

Vol 43, No 3 (2005)

Pages

161-167

Published online

2011-08-22

Bibliographic record

Folia Histochem Cytobiol 2005;43(3):161-167.

Keywords

Y chromosomes
Heterochromatin
Methylation
Histone H3
Rumex

Authors

Magdalena Mosiołek
Paweł Pasierbek
Janusz Malarz
Maria Moś
Andrzej J. Joachimiak

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