0
How do DNA methylation and histone acetylation affect chromatin structure and the regulation of transcription?
Wiki User
∙ 12y ago
When chromatin is tightly compacted and dense, it's called Heterochromatin. When chromatin is loosely packed, its called Euchromatin. Euchromatin is easily accessible to transcription enzymes, while herterochromatin makes transcription impossible because the enzymes cannot access the DNA. Therefore, a gene within heterochromatin cannot be expressed.
Also, look up how histone modifications such as histone acetylation affect gene expression.
Wiki User
∙ 12y ago
Wiki User
∙ 12y agoHistone acetylation loosens chromatin structure
Add your answer:
Earn +20 pts
A threadlike genetic material called chromatin is located within the?
In the inter-phase nucleus of the cell is located a threadlike genetic material called chromatin.
What is the DNA twisted structure called?
AnswerThe "twisted ladder" shape of DNA is called a double helix.
What does prophase do in the cell cycle?
During prophase, the chromatin fibers in the nucleus coil tightly and condense into observable chromosomes. The mitotic spindle then begins to form and the centrosomes move away from each other.
What condensed genetic materials or chromatin that is double stranded?
Condensed genetic material or double stranded chromatin is a chromosome. Chromosomes are long strands of DNA tightly wrapped around histone 'beads' which help to pack it down to fit within the cell. The cells of your body are absolutely tiny, but inside every one of them is close to 2 metres of DNA, so it's absolutely necessary to pack it down as small as possible. The tight structure of chromosomes allows for this, and also aids in making mitosis simpler for the cell.
What are the strands of genetic material floating in a nucleus of a animal cell?
Strands of genetic material floating in the nucleus is chromatin. Cytoplasm is the part of the cell that is between the cell membrane and the nucleus.
What does the term 'histone acetylation' means?
Histones are proteins that organize DNA in the chromatin of eukaryotes (cells that have membrane enclosed nuclei). Acetylation means the introduction of acetyl group to a molecule. In essence, Histone Acetylation removes the positive charge on the histones which, in turn, causes a decrease in the interaction with negatively charged phosphates in DNA.
Why does chromatin remodeling have to be the first step in gene activation?
Eukaryotic DNA can be highly packaged in condensed chromatin and inaccessible to transcription factors and RNA polymerase.
How do chromatin remodeling complexes recognize the genes they should act on?
Chromatin-remodeling complexes recognize specific transcription factors bound to regulatory sequences of DNA.
How do chromatin-remodeling complexes recognize the genes they should act on?
Chromatin-remodeling complexes recognize specific transcription factors bound to regulatory sequences of DNA.
Regulation of gene expression in eukaryotes?
First A. = 'usually involves operons'. 2nd A. = 'No ... that is done by prokaryotes and is a much simpler way of organizing genetic switches and regulating expression. Eukaryotes use a much more complex network involving the likes of enhancers, silencers, insulators, trans and cis acting sequences. Trans acting sequences are sequences which code for particular proteins (like repressor proteins) which bind to operator regions etc. Cis acting are sequences such as operator and promoter regions (usually bound by particular proteins such as repressors or RNAP/DNAP, transcription factors...) and control gene expression within a close proximity and usually found downstream from the operator/promoter. Enhancers are sequences found way upstream from the promoter sequences. These are bound by activator proteins (rather than transcription factors like promoter sequences) and once bound form a loop like structure bringing the bound activator protein to transcription factors and polymerases bound at the promoter region up-regulating gene expression. Silencers work in a similar fashion but bind proteins down-regulating gene expression. Methylation and acetylation of histone tails can bring about the regulation of gene expression. For example acetylation of the lysine residues in histone proteins will nullify the positive charges causing them to have a lower affinity for the negatively charged DNA molecules allowing RNAP and DNAP to associate easier causing up-regulation of gene expression. Methylation leads to hetero-chromatination (facultative hetero-chromatin - also formed through gene silencing from RNAi through siRNA molecules) leading to down regulation of gene expression. Again gene expression can be controlled through the length of the pol-A tail added post-transcriptionally. The length usually determines the half life of the molecule (with a shorter tail causing the destruction of the mRNA a lot more quickly). Also within the 3'untranslated region (between stop codon and 3' end) targets the localization of an mRNA strand within the cytoplasm playing a small role in gene regulation.'
What has the author Gregory James Ide written?
Gregory James Ide has written: 'In vitro transcription in the yeast: Saccharomyces cerevisiae' -- subject(s): Chromatin, Yeast
What uncoiled dna like thread?
Chromatin is the uncoiled form of DNA that resembles a thread-like structure. It consists of DNA wrapped around proteins called histones, which help organize and compact the DNA into a condensed form. When DNA is uncoiled and in the form of chromatin, it allows for easier access and transcription of the genetic information stored in the DNA.
What does the chromatain do?
A chromatin is the material that makes up both mitotic and inter phase chromosomes; a complex of proteins and DNA strands that are loosely coiled such that translation and transcription can occur.
What has the author Joseph Guy Michel Guillemette written?
Joseph Guy Michel Guillemette has written: 'A study of the association between altered chromatin structure and transcription in the Alzheimer afflicted neocortex'
Why chromosomes are not seen inside the nucleus?
In cells that are actively making protien the chromatin can't be seen as easily because it isn't densely packed, but instead stretched out so that the process of transcription is easier.
What happens to the chromatin?
The structure of chromatin during interphase is optimized to allow easy access of transcription and DNA repair factors to the DNA while compacting the DNA into the nucleus. The structure varies depending on the access required to the DNA. Genes that require regular access by RNA polymerase require the looser structure provided by euchromatin
What structure is composed of DNA and protein?
chromatin / chromosones!
