How do chromatin-remodeling complexes work? They use the energy from ATP hydrolysis to alter the arrangement of nucleosomes, rendering certain regions of the DNA more acceible to other proteins. The tails of the core histone proteins can be chemically modified by the covalent addition of what type of chemical group?
What does the chromatin remodeling complex 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 is needed for chromatin remodeling?
Covalent modification of histones by histone acetyltransferase, deacetylase, and methyltransferase, as well as by ATP-dependent protein complexes can also lead to chromatin remodeling. In addition, remodeler complexes can mediate repositioning of nucleosomes.
How do chromatin remodelers change the structure of the chromatin?
Chromatin remodelers have two types of effects on chromatin dynamics: 1) they package genomic DNA, and incorporate histones into the nucleosome, or 2) release DNA from the histones. After DNA replication, chromatin remodelers pack genomic DNA into 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.
How is chromatin remodeled?
Signaling Function of Remodeled Chromatin Histone modification can open chromatin, thus permitting selective binding of transcription factors that, in turn, recruit RNA polymerase II (Turner, 2005). Varying levels and types of histone modifications have been shown to correlate with levels of chromatin activation.
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.
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.
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 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 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.
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.
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 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.
How does histone acetylation affect chromatin structure quizlet?
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.
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 the role of the histone proteins of the chromatin?
Chromatin is a highly organized complex of DNA and proteins and is a principal component of the cell nucleus. Histone proteins help organize DNA into structural units called nucleosomes, which are then assembled into a compact structure (chromatin) and eventually into very large, high-order structures (chromosomes).
What proteins are found in chromatin?
The primary protein components of chromatin are histones. An octamer of two sets of four histone cores (Histone H2A, Histone H2B, Histone H3, and Histone H4) bind to DNA and function as “anchors” around which the strands are wound.
What is the function of the proteins known as histones 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.
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 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.
Which of the following are key differences between eukaryotic and prokaryotic transcriptional regulation quizlet?
Which of the following are key differences between eukaryotic and prokaryotic transcriptional regulation? Combinatorial control of gene expression is more common in eukaryotes. The complexity of eukaryotic development requires that transcription be more coordinated and integrated than in prokaryotes.
What are the characteristics of chromatin quizlet?
Chromatin consists of RNA, DNA, and protein. This organelle is only found in eukaryotic cells. The chromatin has various possibilities of structure. The chromatin’s function can form chromosomes during cell division.