10
votes
Accepted
Do nucleosomes ever completely unwrap during transcription?
Yes, nucleosomes are completely unwound. Histone chaperones such as FACT (for H2A/H2B) and ASF1, CAF-1, HIRA, Nucleophosmin etc (for H3/H4), associate with RNA Pol II and handle the displaced ...
- 515
4
votes
Accepted
DNA-DNA cross-linking with formaldehyde?
The fact that there is no inter-strand cross-linking between different double strands might be just because the cross-linker cannot bridge the distance between amines of different bases on different ...
- 131
3
votes
Accepted
Heterochromatin v Euchromatin. Which is more abundant?
Percentage of euchromatin varies between cell types and organisms. It has been shown that upto 88% of the human genome is transcribed; a phenomenon called pervasive transcription [1]. Highly ...
- 35.1k
2
votes
Why is it important to study chromatin to understand cancer?
Most cancers involve, in addition to genetic changes, a whole suite of epigenetic changes that orchestrate changes in transcriptional profiles. Additionally, multiple epigenetic modifiers (Eg - EZH2) ...
- 1,294
2
votes
Why are GC-rich regions less condensed than GC-poor regions?
@ThoH.Ho and @Thawn. When banding chromosomes they are first treated with trypsin before staining with Giemsa dye. My understanding, and I have worked in the field of cytogenetics for quite a while, ...
- 21
2
votes
Accepted
Meaning of the word "targeted" in a description of chromatin immunoprecipitation
Looking at the article, I think they could leave out the word "targeted".
I think they used it because what is being enriched is not a promoter DNA, but the section of promoter DNA bound to ...
- 2,688
2
votes
Accepted
Can Euchromatin convert into Heterochromatin?
I would suggest in the future doing a small amount of research before asking. For example, the wikipedia page for euchromatin says this:
Euchromatin participates in the active transcription of DNA to ...
- 7,385
2
votes
Accepted
What are "anchor regions" in the human genome?
Good question. Anchor regions are regions that connect to the nuclear matrix. More specifically, in eukaryotic organisms, chromatin is anchored to the nuclear matrix by short DNA sequences of about ...
- 3,675
2
votes
In chromatin, what are the differences among states, interactions, and structures?
Chromatin state refers to the marks (i.e. methylated DNA, histone modifications, euchromatin v. heterochromatin) found at specific loci and is often referred to as open (readily bound by DNA binding ...
- 700
1
vote
Accepted
What’s so remarkable about position effect variegation?
Re:
In particular, if the underlying DNA structure is changing, then
wouldn’t we expect the progeny to inherit these epigenetic changes?
Why is it so remarkable?
Given the context of the quote, the &...
- 1,699
1
vote
Properties of Satellite Chromosomes
If by "satellite chromosomes" you mean "satellite repeats", then:
Not always. There many types of satellites, such as telomeric, centromeric (like gamma, alpha, beta satellites), simple repeats (CT)n....
- 213
1
vote
Can untargeted metabolomics detect epigenomic changes such as methylation?
This is a fascinating question, and I spent a fair amount of time looking into it. From what I've been able to find regarding the relationship between metabolics and epigenetics, it seems that ...
- 491
1
vote
Accepted
How do you read the histone code?
The "histone code" is not like the genetic code where one codon in an ORF always is translated to a single amino acid. It's closer to something like GC content or CpG islands: a single instance doesn'...
- 3,043
1
vote
Why are GC-rich regions less condensed than GC-poor regions?
Chromosome condensation seems to be primarily driven by epigenetic factors like methylation and histone modifications, not GC content. However, high GC content is associated with gene rich regions and ...
- 3,043
1
vote
Why does cell waste energy in meiosis, between meiosis 1&2
There is a phase between meiosis 1 and meiosis 2 called Interkinesis.
During this phase centrosomes or centriole pairs undergo replication in animal cells, which is important for bringing true ...
- 123
1
vote
Dnase data for GRCh38
I am unsure that how much does it answer your question, but have a look at the homepage of DeltaSVM - In his work, Lee et al. have used similar datasets (only for GRCH37 I reckon) and I am sure they ...
- 1,609
1
vote
Transcription when Chromosomes are Condensed
The compaction of DNA into chromatin is a very complex process that involves not only DNA, but on the histone code. Some may say that the histone code plays more of a role in chromatin state To ...
- 335
1
vote
What happens after the purification step in Hi-C sequencing?
So, after the restriction digestion, the sample consists of DNA fragments with 5' overhangs. These are filled in by Klenow DNA polymerase, adding biotin-dCTP to both ends of each fragment. Then the ...
- 17.5k
1
vote
What is the mechanism by which lamins regulate gene expression?
So my answer was deleted because it "didn't answer your question." Except that it did. The article linked here, Gene expression, chromosome position and lamin A/C mutations, is an entire ...
- 1,309
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