Exam 2 Flashcards
What happens during elongation?
-RNA POL II+ TFIID move down DNA and start txn @ +1
- RNA POL II continues to unwind DNA generating RNA 5’ →3’
What happens in termination?
-mRNA IS PRODUCED
-AAUAAA (polyadenylation signal sequence) signals to stop and signals generation of 3 poly A tail.
- rat 1 nuclease (enzyme) digest excess RNA until it reaches RNA Pol II AND SYSTEM COLLAPSES
Cis acting elements
DNA sequence near gene regulate txn
Ex. GC box or CAT box near 100 Bp from gene
Enhancer sequence
DNA sequence far from the gene to which an activator protein can bind
Silencer sequence
DNA sequence far from gene to which a repressor protein can bind
Multiple response elements
When various proteins may binding to upstream response elements to stimulate transcription
Do eukaryotes use operon? If not, what do they use?
Eukaryotes use similar enhancers, sequences and multiple copies of activator proteins to coordinate gene expression
What can an activation domain do
Bind to BTM and other TF and can modify chromatin structure
Six ways to repress txn
- Competitive DNA binding
- Making activation surface
- Direct interaction with general txn factors
- Recruitment of chromatin remodeling complex
- Recruitment of histone deacetylase
- Recruitment of histone methyl transferase
What are the two types of chromosomes?
Nucleusomes and chromatosome
What is the structure of nucleosomes
8 histone proteins (H2A,H2B,H3,H4 x2)
What is the structure of chromatosomes?
8 histone proteins (H2A,H2B,H3,H4 x2)+ H1
What is the structure of chromatin
His stone proteins wrapped by DNA. The histone proteins are called histone fold domain. While the tails hanging out are called amino terminal tailed domains.
What are the two types of chromatin?
Euchromatin- expressed/used chromatin
Heterochromatin - highly condensed chromatin
When is euchromatin used?
During transcription and replication
