Cytological study of DNA methylation and histone methylation patterns in human cell lines
| Authors | |
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| Year of publication | 2004 |
| Type | Article in Proceedings |
| Conference | Biophysics of the Genome |
| MU Faculty or unit | |
| Citation | |
| Field | Genetics and molecular biology |
| Keywords | cytometry |
| Description | Epigenetic processes are defined as heritable changes in genome function that occur without a change in DNA sequence. Gene expression, chromosome segregation, DNA replication, repair, and recombination all act, not on DNA alone, but on the chromatin template. DNA methylation, along with histone lysine methylation, establishes the framework for long-term epigenetic maintenance. The discovery that enzymes can (re)organise chromatin into accessible and inaccessible configurations revealed epigenetic mechanisms that considerably extend the information potential of the genetic code. In mammals, heterochromatin is characterised by DNA methylation at CpG dinucleotides and methylation at lysine 9 of histone 3 (H3- K9), whereas euchromatin is associated with methylation at lysine 4 of histone 3 (H3-K4). In our experiments, the detection of DNA methylated regions at chromosomal level was performed using indirect immunofluorescence technique combined with FISH. The selected metaphase chromosomes HSA 2 were determined using FISH. Sequential 5-methylcytosin rich regions were visualised using immunofluorescent labelling in retinoblastoma cell line Y79 and in leukemic cell line K562. Our model study is partly focused on the global histone H3-K4 and H3-K9 trimethylation studied by qualitative immunohistochemistry in retinoblastoma cells Y79 and leukemic cells K562. Our results highlight the importance of the relationships between histone modifications and DNA methylation, however the mutual connection between individual epigenetic hereditary mechanisms has not been made clear yet. |
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