DNA methylation patterns of Melandrium album chromosomes.
Melandrium album (syn. Silene latifolia) belongs to dioecious plant species possessing heteromorphic sex chromosomes, X and Y. Our previous experiments using in situ nick translation and replication kinetics analysis indicated structural and functional differences between the two X chromosomes in homogametic female cells. Here we show DNA methylation patterns of M. album root tip chromosomes using the indirect immunofluorescence approach with a monoclonal antibody raised against 5-methylcytosine (5-mC). In male cells, a more intensive 5-mC labelling on the shorter arm of the only X chromosome was observed in comparison with the longer X arm. A global hypermethylation of the male Y chromosome was not found, which indicates its prevalent euchromatic character. In female cells, the specific 5-mC pattern of the X chromosome was found on a single X chromosome, whereas the other X displayed an overall higher level of 5-mC labelling. Application of a hypomethylating drug, 5-azacytidine (5-azaC), during seed germination led to a deletion of any specific differences in the 5-mC distribution between the two X chromosomes. Confocal laser scanning microscopy analysis of DNA methylation in interphase nuclei showed hypermethylated domains that were efficiently decondensed and hypomethylated by 5-azaC treatment. The presented data show reproducible differences in the DNA methylation patterns between the two X chromosomes in M. album female somatic cells, which indicate their distinct transcriptional activities as a possible consequence of the negative dosage compensation of X-linked genes.
Siroky
J
J
Institute of Biophysics, Czech Academy of Sciences, Brno, Czech Republic. siroky@ibp.cz
Castiglione
M R
MR
Vyskot
B
B
D001374:Azacitidine / Q000494:pharmacology; D002843:Chromatin / Q000378:metabolism; D019175:DNA Methylation; D019084:Fluorescent Antibody Technique, Indirect; D018613:Microscopy, Confocal / Q000379:methods; D010944:Plants / Q000235:genetics*; D014960:X Chromosome; D014998:Y Chromosome
D002843:Chromatin; D001374:Azacitidine