Question: H3K4me3 in promoter regions, which are free of nucleosomes
gravatar for panacotaforcota
18 months ago by
panacotaforcota0 wrote:


I'm trying to deal with histone mark and their localization on the genome. I read that marks H3K4me3 are localized in the promoter regions. But I know that promoters are free of nucleosomes. How is this possible? Do I understand correctly that the presence of histone marks from an experiment Chip-seq means the presence of a nucleosome in this region? I read several articles, but did not find the answer.

I will be glad to any answer, especially useful articles on this topic.

ADD COMMENTlink modified 18 months ago by ATpoint46k • written 18 months ago by panacotaforcota0
gravatar for ATpoint
18 months ago by
ATpoint46k wrote:

Promoters are not free of nucleosomes but there is a nucleosome-free stretch of DNA at which the DNA-binding machinery assembles. This is flanked by histones that undergo modifications at, e.g. their lysin tails (K4).

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ADD COMMENTlink written 18 months ago by ATpoint46k

Thank you very much! It becomes clearer. So, is it true that the data from the Chip-seq experiment correspond to the active state? Or is it an inactive state, but with histone marks that are there all the time?

ADD REPLYlink written 18 months ago by panacotaforcota0

There is some research that has found H3K4me3 is generally found in all high CpG promoters (the majority in human) regardless of transcriptional activity, but are only present at low CpG promoters when the gene is actively transcribed ( ). H3K27ac may be more predictive of active transcription at promoters/TSS than H3K4me3 (see ).

ADD REPLYlink modified 18 months ago • written 18 months ago by colin.kern950

Thank you for these articles! Exactly what is needed!

ADD REPLYlink written 18 months ago by panacotaforcota0

From what I understand H3K4me3 is often referred to as a "promoter mark", even though it boils down to an indication for active transcription.

ADD REPLYlink written 18 months ago by ATpoint46k
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