September 2013 | What is Epigenetics?

Deacetylation of Neighbor Nucleosomes by Rpd3S dna chromosome epigenetics

Chromatin Remodelers Fine-Tune H3K36me-Directed Deacetylation of Neighbor Nucleosomes by Rpd3S

September 30, 2013 Milka Rodriguez

To form chromatin, DNA is tightly wrapped around nuclear proteins called histones. The repeating DNA-histone complex, which consists of 146 base pairs of double-stranded DNA wrapped around eight core histone proteins (H2A, H2B, H3 and H4), is called a nucleosome. Histone proteins are involved in structural organization of chromatin in eukaryotic cells. They can undergo various posttranslational modifications (PTMs) such as methylation/demethylation and acetylation/deacetylation, which can alter their interaction with DNA and nuclear proteins resulting in remodeling of chromatin structure [more…]

Epigenetic Memory at Embryonic Enhancers Identified in DNA Maps from Adult Mouse Tissues

September 13, 2013 Milka Rodriguez

In human DNA, 5-methylcytosine is found in approximately 1.5% of genomic DNA. In somatic cells, 5-mC occurs almost exclusively in the context of paired symmetrical methylation of a CpG site. An exception to this is seen in embryonic stem (ES) cells, where a substantial amount of 5-mC is also observed in non-CpG contexts. In the bulk of genomic DNA, most CpG sites are heavily methylated while CpG islands (sites of CpG clusters) in germ-line tissues and located near promoters of [more…]

DNA methylation individual cell nuclei and chromosomes epigenetics

Sequence-specific microscopic visualization of DNA methylation status at satellite repeats in individual cell nuclei and chromosomes

September 13, 2013 WhatIsEpigenetics

Scientists from Japan developed methylation-specific fluorescence in situ hybridization (MeFISH) for microscopic visualization of DNA methylation status at specific repeat sequences in individual cells. MeFISH is based on the differential reactivity of 5-methylcytosine and cytosine in target DNA for interstrand complex formation with osmium and bipyridine-containing nucleic acids (ICON). Cell nuclei and chromosomes hybridized with fluorescence-labeled ICON probes for mouse major and minor satellite repeats were treated with osmium for crosslinking. After denaturation, fluorescent signals were retained specifically at satellite [more…]

epigenetic in vivo inhibition or silencing of microRNA

Targeting Noncoding RNAs in Disease: Challenges and Opportunities

September 13, 2013 WhatIsEpigenetics

Noncoding RNAs make up the majority of transcribed RNA and have a wide range of functions in cellular and developmental processes. Consequently, they are also implicated in the development and pathophysiology of many diseases and represent potential targets for therapeutic intervention. Scientists found that effective in vivo inhibition (or silencing) of microRNA, one class of noncoding RNA, has enabled to make groundbreaking discoveries about the contribution of these short regulating RNAs to some of the major human diseases, such as [more…]

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