How does histone acetylation affect chromatin structure? acetylation of lysine residues by AcCoA neutralizes the positive charge of the histone N-terminus “tails”, which decreases the affinity of histones for DNA.
What are 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.
What effect can ATP dependent chromatin remodeling have on transcription?
ATP-dependent chromatin alteration is accomplished by several multi-subunit chromatin-remodeling complexes that utilize energy derived from ATP hydrolysis to alter nucleosome structure or conformation and, thereby, regulate the access of transcription factors to their cognate DNA binding sites.
Do chromatin remodeling complexes require ATP?
Two-step model of SWI/SNF and RSC action in chromatin remodeling. The binding of the remodeling complex to chromatin is ATP independent (A). Upon ATP addition, the conformation of nucleosomes changes as a consequence of the alteration of histone-DNA interactions (B).
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 do chromatin remodeling complexes do?
Chromatin remodeling is the dynamic modification of chromatin architecture to allow access of condensed genomic DNA to the regulatory transcription machinery proteins, and thereby control gene expression.
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.
Why is ATP necessary 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.
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 role of chromatin in transcriptional regulation?
In order to activate transcription, some of the specific transcription factors must have the capacity to bind to their binding sites when organized into nucleosomes. As a next step, the chromatin structure of the promoter needs to be decondensed in order to facilitate the binding of the basal transcription machinery.
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.
What is the function of histone deacetylase?
Histone deacetylases (HDACs) are enzymes that catalyze the removal of acetyl functional groups from the lysine residues of both histone and nonhistone proteins.
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 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.
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. Some forms of chromatin modification can be passed on to future generations of cells.
How do chromatin remodeling complexes recognize the genes?
The many different remodeling enzymes recognize different histone modifications, DNA structures/sequences and RNA signals that target them to specific genomic loci. To recognize these chromatin signals remodeling complexes have dedicated protein domains, termed reader domains.
What are the two classes of proteins found in chromatin?
The main factors that determine whether chromatin is in a DNA-packaging or -unpacking state are chromatin-regulating proteins, also known as chromatin regulators. The two classes of chromatin regulators are 1) histone-modifying enzymes and 2) chromatin-remodeling enzymes.
Which proteins are responsible for directly binding to chromatin in remodeling and packing?
To form chromatin, DNA is tightly condensed by being wrapped around nuclear proteins called histones. This repeating DNA-histone complex, which consists of 146 base pairs of double-stranded DNA wrapped around eight histone proteins, is called a nucleosome.
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 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 are histones modified?
Histone modification includes acetylation, methylation, phosphorylation, ubiquitination, and sumoylation. Histone acetylation, addition of acetyl groups to lysine residue at the histone tail, is important for histones packaging of DNA into nucleosomes, the basic unit of chromatin (seeFig. 73.5).
Why are interactions between RNA polymerase II and GTFs important for transcription in eukaryotes?
Interactions between RNA polymerase and GTFs increase the rate of transcription because GTFs act as enhancers. RNA polymerase II and GTFs must interact for the polymerase to bind properly at the core promoter site of the DNA.
What does histone code refer to?
 The “histone code” is a hypothesis which states that DNA transcription is largely regulated by post-translational modifications to these histone proteins.  Through these mechanisms, a person’s phenotype can change without changing their underlying genetic makeup, controlling gene expression.
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.
Which of the following is a function of histones in the process of gene expression quizlet?
Histones are proteins that condense and structure the DNA of eukaryotic cell nuclei into units called nucleosomes. Their main functions are to compact DNA and regulate chromatin, therefore impacting gene regulation.