Is chromatin remodeling and nucleosome remodeling same?

It is important to distinguish nucleosome remodeling from other forms of epigenetic mechanisms. Nucleosome (chromatin) remodeling specifically refers to the ATP-dependent enzymatic complexes (e.g., nBAF, SWI/SNF, INO80, ISWI, NURD) that are involved in nucleosome mobility underlying transcriptional regulation.

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How does chromatin remodeling affect nucleosomes?

This modification results in a loosening of the coil. Other remodeling enzyme complexes actually slide the nucleosomes along the DNA to clear them from the promoter regions (Cosgrove et al., 2004). In this case, the remodeling enzymes use the energy from ATP to regulate nucleosome movement.

What does chromatin remodeling affect?

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.

How do chromatin remodelers change the structure of the chromatin?

In contrast to histone modifications, which do not require energy, chromatin remodeling is an energy-driven process in which chromatin remodelers use the energy of ATP hydrolysis to change the nucleosome structure [49, 50].

What are chromatin remodeling factors?

Chromatin remodeling factors are key components involved in this process and include histone chaperones, histone modifying enzymes and ATP-dependent chromatin remodeling complexes. Several of these factors interact directly with components of the replication machinery.

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 action of nucleosome remodeling complexes?

Nucleosome remodeling complexes are involved in both the activation and repression of gene expression. Mutation of their subunits in yeast often leads to as many genes showing an increase in expression as those whose expression decreases (Hargreaves and Crabtree 2011).

What is meant by the term chromatin remodeling quizlet?

What is meant by the term chromatin remodeling? Chromatin remodeling includes altering chromatin structure by altering the composition of histones within nucleosomes. Chromatin remodeling includes altering chromatin structure by altering the positioning of nucleosomes with respect to specific DNA sequences.

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.

How does chromatin Remodelling increase transcriptional initiation?

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.

What are three ways in which gene regulation is accomplished by modifying the structure of chromatin?

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.

How are nucleosomes modified?

Altering the location of nucleosomes and the tightness of histone binding opens some regions of chromatin to transcription and closes others. The DNA molecule itself can also be modified by methylation. DNA methylation occurs within very specific regions called CpG islands.

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 the structure of chromatin related to gene expression?

DNA is stored in a highly structured complex called chromatin. Epigenetic processes control gene expression by altering chromatin structure (Figure 1). Actively transcribed genes are associated with accessible chromatin regions, while transcriptionally silent genes are found in inaccessible chromatin regions.

How chromatin structure can be modified in eukaryotes and how these modifications regulate gene expression?

Chromatin structure can be demethylated with the help of DNA demethylase that helps in the removal of the methyl group. DNA demethylation can activate gene expression. 3. Chromatin structure is tightly associated with proteins known as histone proteins which can be acetylated.

What is the structure of nucleosome?

Each nucleosome is composed of a little less than two turns of DNA wrapped around a set of eight proteins called histones, which are known as a histone octamer. Each histone octamer is composed of two copies each of the histone proteins H2A, H2B, H3, and H4.

Why is the structure of a nucleosome so important?

Nucleosomes are thought to carry epigenetically inherited information in the form of covalent modifications of their core histones. Nucleosome positions in the genome are not random, and it is important to know where each nucleosome is located because this determines the accessibility of the DNA to regulatory proteins.

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. elegans, D.

How does chemical modification of histones lead to changes in chromatin structure?

Answer and Explanation: Histone modifications lead to the change in chromatin structure, because it’s alters the affinity between the histone optima and the dna. Histone modification has no effect on the position of histones which are set during DNA replication.

Why does chromatin compaction affect gene expression quizlet?

When chromatin is condensed, DNA is not accessible for transcription. Acetylation of histone tails reduces the attraction between neighboring nucleosomes, causing chromatin to assume a looser structure and allowing access to the DNA for transcription.

What is ATP dependent chromatin nucleosome remodeling?

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.

What is the role of ATP dependent chromatin remodeling?

ATP-dependent chromatin remodelers have established roles in regulating gene expression. Chromatin remodeling complexes (CRCs) are made up of multiple specialized proteins that play essential roles in packaging and regulating access to the genome throughout the cell cycle.

Why is ATP needed for chromatin remodeling?

ATP-dependent chromatin remodeling complexes use the energy of ATP hydrolysis to alter chromatin architecture by repositioning, assembling, mobilizing, and restructuring nucleosomes.

How does chromatin remodeling affect gene expression?

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.

Which molecular processes will enhance the formation of higher order structure in heterochromatin?

Formation of higher-order structures in heterochromatin depends upon posttranslational modifications of , binding of proteins to , and DNA .

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