To form chromatin, DNA is tightly condensed by being wrapped around nuclear proteins called histones. … Epigenetic modifications to histone proteins such as methylation/demethylation and acetylation/deacetylation can alter the structure of chromatin resulting in transcriptional activation or repression.
What causes changes in chromatin structure?
A major mechanism in the epigenetic regulation of chromatin is the post-translational modification of histone proteins. Mutation or deregulated expression of histone modifying or de-modifying enzymes can lead to altered deposition of modification marks.
How is chromatin structure regulated?
Chromatin accessibility is regulated by nucleosome remodeling, utilization of histone variants, DNA methylation, and posttranslational modifications (PTMs). Chromatin remodeling complexes can slide nucleosomes, rotate the DNA helix relative to the nucleosome to expose TF binding sites, or evict nucleosomes.
What are three ways in which gene regulation is accomplished by modifying the structure of chromatin?
Gene regulation is defined as the control of a gene’s transcript and its protein product. It can be achieved by altering either the transcription of the gene (RNA level), the translation of the protein from that transcript or by altering the structure of DNA such that transcription cannot occur.
Does chromatin have RNA?
Whether RNA itself plays a direct structural role in chromatin is, however, not known. Here, we report results indicating that RNA plays a general structural role in eukaryotic chromatin. Our results indicate that purified chromatin contains significant amounts of RNA (2%–5% of total nucleic acids).
What are the two components of chromatin?
Chromatin exists in two forms: heterochromatin (condensed) and euchromatin (extended). The primary protein components of chromatin are histones that help to organize DNA into “bead-like” structures called nucleosomes by providing a base on which the DNA can be wrapped around.
What does chromatin look like?
Under the microscope in its extended form, chromatin looks like beads on a string. The beads are called nucleosomes. Each nucleosome is composed of DNA wrapped around eight proteins called histones.
Does chromatin regulate gene expression?
In eukaryotes, the tight or loose packaging of the genes in chromatin (DNA plus specific proteins) can control whether the genes can be expressed to form their encoded product. DNA itself can be methylation and that also regulates gene expression, generally to turn off the gene. …
What is the general name given to the most highly condensed form of chromatin?
Essential Cell Biology: DNA and Chromosomes
|21) What is the most highly condensed form of chromatin?||Heterochromatin|
|22) Histone tail modifications establish and maintain the different chromatin structures found in heterochromatin and euchromatin. True or False?||True|
Which of the following is an example of post transcriptional gene regulation?
Post-transcriptional regulation includes processes of regulation between transcription and translation such as RNA splicing, capping, addition of poly-A tail, RNA editing.
What is the process of gene regulation?
Gene regulation is the process of turning genes on and off. During early development, cells begin to take on specific functions. … Gene regulation is accomplished by a variety of mechanisms including chemically modifying genes and using regulatory proteins to turn genes on or off.