Relationship between epigenetic marks and the behavior of 45S rDNA sites in chromosomes and interphase nuclei of Lolium-Festuca complex.
The grasses of the Lolium-Festuca complex show a prominent role in world agricultural scenario. Several studies have demonstrated that the plasticity of 45S rDNA sites has been recently associated with the possible fragility of the loci. Often, these fragile sites were observed as extended sites and gaps in metaphases. This organization can be evaluated in relation to their transcriptional activity/accessibility through epigenetic changes. Thus, this study aimed to investigate the relationship of the 5-methylcytosine and histone H3 lysine-9 dimethylation in different conformations of 45S rDNA sites in interphase nuclei and in metaphase chromosomes of L. perenne, L. multiflorum and F. arundinacea. The FISH technique using 45S rDNA probes was performed sequentially after the immunolocalization. The sites showed predominantly the following characteristics in the interphase nuclei: intra- and perinucleolar position, decondensed or partially condensed and hypomethylated and hyper/hypomethylated status. Extranucleolar sites were mainly hypermethylated for both epigenetic marks. The 45S rDNA sites with gaps identified in metaphases were always hypomethylated, which justifies it decondensed and transcriptional state. The frequency of sites with hypermethylated gaps was very low. The structural differences observed in these sites are directly related to the assessed epigenetic marks, justifying the different conformations throughout the cell cycle.
['Ferreira|Marco Tulio Mendes|MTM|http://orcid.org/0000-0002-2526-354X', 'Rocha|Laiane Corsini|LC|http://orcid.org/0000-0003-2071-1769', 'Vitoriano|Matheus Braga Zanon|MBZ|http://orcid.org/0000-0002-1724-0823', 'Mittelmann|Andréa|A|http://orcid.org/0000-0003-1845-4273', 'Techio|Vânia Helena|VH|http://orcid.org/0000-0002-3752-0654']
D044503:5-Methylcytosine D002453:Cell Cycle D002467:Cell Nucleus D043283:Chromosome Fragile Sites D032461:Chromosomes, Plant D019175:DNA Methylation D004275:DNA, Ribosomal D044127:Epigenesis, Genetic D057890:Epigenomics D031751:Festuca D017404:In Situ Hybridization, Fluorescence D007399:Interphase D008129:Lolium D008677:Metaphase D012335:RNA, Ribosomal
Epigenetic marks Fragile sites Lolium–Festuca complex Post translational modification