Chromatin remodeling plays a central role in the regulation of gene expression by providing the transcription machinery with dynamic access to an otherwise tightly packaged genome.
What does chromatin remodeling do?
Chromatin remodeling is the rearrangement of chromatin from a condensed state to a transcriptionally accessible state, allowing transcription factors or other DNA binding proteins to access DNA and control gene expression.
How does chromatin remodeling affect transcription?
As chromatin is condensed into the primary nucleosome structure, DNA becomes less accessible for transcription factors. With the loosening of this chromatin structure, however, transcription machinery is better able to access the genomic DNA, and transcription is thus promoted.
Are chromatin remodeling complexes transcription factors?
To activate a gene, proteins called transcription factors bind to a section of DNA within the gene called the promoter. Enzymes known as ‘chromatin remodelers’ can alter the locations of nucleosomes on DNA to allow the transcription factors access to the promoters of particular genes.
Why is chromatin Remodelling important?
Chromatin remodeling is an important mechanism of regulating eukaryotic gene expression, which makes tightly condensed DNA accessible to various regulatory factors, such as transcription factors and components of DNA replication.
What is the function of chromatin-remodeling complexes quizlet?
How do chromatin-remodeling complexes work? Chromatin-remodeling complexes use energy from ATP hydrolysis to alter the arrangement of nucleosomes, making the DNA more accessible to other proteins.
What is the chromatin Remodelling complex?
Chromatin Remodeling at a Glance Currently, investigators know that chromatin remodelers are large, multiprotein complexes that use the energy of ATP hydrolysis to mobilize and restructure nucleosomes.
What does the chromatin remodeling complex expose on the DNA that affects transcription?
There is also evidence that chromatin-remodeling complexes work together with enzymes that alter histones, such as acetyltransferase enzymes (see next section), to change chromatin structure and expose DNA for transcription.
What role do chromatin remodelers play in eukaryotic gene expression quizlet?
What role do chromatin remodelers play in eukaryotic gene expression? Chromatin remodeler enzymes can enzymatically change the distribution or composition of nucleosomes (histone octamers). a eukaryotic cis-acting DNA regulatory sequence to which transacting factors bind and stimulate transcription.
How is chromatin remodeled quizlet?
Chromatin Remodeling Complex: slide the nucleosome to a different location or eject it from the DNA or replace it with a new nucleosome that contains a variant histone subunit.
What is the function of ATP dependent chromatin-remodeling complexes quizlet?
ATP-dependent chromatin remodeling may effect position of nucleosomes, evict histones, and may replace histones with histone variants. The addition of methyl groups to bases of DNA after DNA synthesis. Inhibits initiation of transcription when occurs near promoter.
What is the function of ATP dependent chromatin-remodeling complexes?
ATP dependent remodeling complexes mobilize nucleosomes along DNA, promote the exchange of histones, or completely displace nucleosomes from DNA. These remodeling complexes are often categorized based on the domain organization of their catalytic subunit.
Why are chromatin structure changes essential for transcription in eukaryotic cells?
In eukaryotic cells, chromatin structure plays a role in gene regulation. of histone proteins and DNA methylation are important in these changes.
Which DNA repair mechanism are DNA glycosylase inhibitors used to study?
Base excision repair is the mechanism by which damaged bases in DNA are removed and replaced. DNA glycosylases catalyze the first step of this process. They remove the damaged nitrogenous base while leaving the sugar-phosphate backbone intact, creating an apurinic/apyrimidinic site, commonly referred to as an AP site.
Which of the following is a primary function of the SWI SNF complex?
What is the primary function of the SWI/SNF complex? to open chromatin structure by displacing or ejecting nucleosomes.
What part of the chromatin fiber does the remodeling complex attach to quizlet?
book: (A) Using the energy of ATP hydrolysis, the remodeling complex is thought to push on the DNA of its bound nucleosome and loosen its attachment to the nucleosome core.
Which of the following is a nucleosome chromatin remodeling complex?
The only chromatin remodeling complex purified so far is the NuRD complex that couples ATP dependent nucleosome remodeling with histone deacetylation. The transcription repressive ability of the complex has been studied in various genes involved in differentiation and development of C.
How does methylation of histone tails affect the accessibility of DNA quizlet?
Methylation of histone tails in chromatin can promote condensation of the chromatin. Acetylation of histone tails in chromatin allows access to DNA for transcription. One of the mechanisms by which eukaryotes regulate gene expression is through modifications to chromatin structure.
What is the name of the protein that binds the two separated DNA strands to keep them from base pairing again before they can be replicated?
FEEDBACK: As a replication fork travels along the chromosome, the helicase pries apart the two strands of the double-helix. Single-strand binding protein holds these two strands apart and keeps them from reforming base pairs by binding to the single-stranded DNA.
What are the basic components of the lac operon quizlet?
- Operon. A set of adjacent genes that are transcribed in a polycistronic mRNA and thus are coordinately regulated.
- Operator. Regulatory DNA sequence that a repressor or activator binds to.
- RNA polymerase.
- Activator protein.
- Repressor protein.
Are chromatin remodeling complexes Atpases?
All of the ATP-dependent chromatin-remodeling complexes contain an ATPase subunit that belongs to the SNF2 superfamily of proteins. Based on the identity of this subunit, they have been classified into two main groups, the SWI2/SNF2 group and the imitation SWI (ISWI) group (25).
When transcription is regulated by repressor proteins this is called?
genes. When a gene has constant levels of expression over time in a cell, it is: constitutive gene. When transcription is regulated by repressor proteins, this is called: negative control.
How are histones modified?
At least nine different types of histone modifications have been discovered. Acetylation, methylation, phosphorylation, and ubiquitylation are the most well-understood, while GlcNAcylation, citrullination, krotonilation, and isomerization are more recent discoveries that have yet to be thoroughly investigated.
What is one mechanism by which chromatin remodeling complexes reposition nucleosomes?
What is one mechanism by which chromatin-remodeling complexes reposition nucleosomes? They directly promote histone acetylation that allows chromatin remodeling. They promote nucleosome disassembly and reassembly at another site within the chromatin.
How does chromatin structure affect gene regulation?
Higher order chromatin structure and organization contributes to gene expression regulation. Thus, it is possible that the diverse lifetimes of accessibility and activation of distal regulatory elements could contribute to the observed divergent patterns of gene regulation through combinatorial long-range interactions.