What are primed enhancers?
Primed enhancers display similar chromatin features as repressed elements. They are characterized by accessible chromatin conformation and exhibit H3K4me in the absence or reduction of H3K27ac.
What does an enhancer do?
Enhancers are regulatory deoxyribonucleic acid (DNA) sequences that provide binding sites for proteins that help activate transcription (formation of ribonucleic acid [RNA] by DNA). When the proteins that have a special affinity for DNA (DNA-binding protein) bind to an enhancer, the shape of the DNA changes.
What is the difference between H3K4me1 and H3K4me3?
If it is the DNA methylation, the region is inactive. If it is H3K4me1, the region is an enhancer, and if it is H3K4me3, the region is a promoter”. To test our model, we used available genome-wide datasets of H3K4 methyltransferases knockouts.
What are poised promoters?
Poised (bivalent) chromatin is defined by the simultaneous presence of histone modifications associated with both gene activation and repression. This epigenetic feature was first observed at promoters of lineage-specific regulatory genes in embryonic stem cells in culture.
Where do silencers bind?
There are many positions in which a silencer element can be located in DNA. The most common position is found upstream of the target gene where it can help repress the transcription of the gene. This distance can vary greatly between approximately -20 bp to -2000 bp upstream of a gene.
What is the difference between an enhancer and an activator?
An enhancer is a DNA sequence that promotes transcription. Activators bound to the distal control elements interact with mediator proteins and transcription factors. Two different genes may have the same promoter but different distal control elements, enabling differential gene expression.
What does H3K4 stand for?
H3K4me3 is an epigenetic modification to the DNA packaging protein Histone H3. It is a mark that indicates the tri-methylation at the 4th lysine residue of the histone H3 protein and often involved in the regulation of gene expression.