Notesale: Turn your study into money

Document Preview

Extracts from the notes are below, to see the PDF you'll receive please use the links above

---

Blueprint Series

Complete Solution
Chapter 9

9
TRANSCRIPTIONAL CONTROL
OF GENE EXPRESSION

REVIEW THE CONCEPTS
1
...
After shifting to lactose media,
lactose is transported into the cell where it binds the lac repressor
...
In addition, the cell synthesizes cAMP because
of the low concentration of glucose
...
The lac promoter is a weak promoter in the absence of CAP binding; CAP bound at the CAP site
stimulates RNA polymerase binding and transcription initiation at the lac promoter,
resulting in a high rate of transcription from the lac promoter and maximal induction
of the lac operon
...
In two-component regulatory systems, one protein acts as a sensor and the other
protein is a response regulator
...
coli the proteins NtrB (the sensor) and NtrC
(the response regulator) regulate transcription of glutamine synthetase in response
to the free glutamine concentration
...
Under low glutamine conditions, NtrB undergoes a conformational change that activates the protein
kinase activity and results in the transfer of a phosphate group to NtrC
...


33

34

CHAPTER 9: Transcriptional Control of Gene Expression

3
...

b
...

d
...
Similarities:
Both employ protein-binding regulatory DNA sequences/control elements
and specific proteins that bind to these regulatory sequences to control gene transcription
...

Regulatory proteins are able to influence gene transcription by binding to
regulatory sequences proximal or distal to the transcription start site in eukaryotes
...

5
...
RNA
polymerase II is responsible for mRNA transcription
...
Since RNA polymerase
II is uniquely inhibited by a low concentration of a-amanitin, one can determine
if any gene requires this polymerase by measuring gene transcription in the
presence and absence of this compound
...

6
...
The CTD is then further phosphorylated by cyclin T-CDK9
...

7
...
The TATA
box was the first to be identified because it is found in the promoters of most
genes expressed at high level
...
Since the TATA box occurs at a fixed location relative to the
transcription start site (~30 bases upstream), it was relatively easy to recognize
in the DNA sequence
...
To identify DNA-control elements within promoter regions, investigators utilize
5’ deletion mutants and linker scanning mutants
...
The wild-type DNA sequence and mutated
DNA are separately introduced into cultured cells, or transgenic animals are generated with the wild-type and mutant DNA
...
When an activator-binding
site is deleted, expression is reduced

---