nan hao, erin k o’shea. + how is an environmental stimuli transmitted into a cell? + how a cell...
TRANSCRIPT
SIGNAL-DEPENDENT DYNAMICS OF TRANSCRIPTION FACTOR
TRANSLOCATION CONTROLS GENE EXPRESSION
Nan Hao , Erin K O’Shea
+ How is an environmental stimuli transmitted into a cell?
+ How a cell respond to a specific signal?– Here the signal can be any change in the
environment.
Signal&
Response
RESPONSE
http://howardhughes.trinity.duke.edu/blogs/2011/06/24/zinc-fingers-plasmids-and-my-battle-with-e-coli
OBSERVATION—FLUORESCENT PROTEIN
http://www.michaeleisen.org/blog/wp-content/uploads/2008/10/fps.png
TRANSCRIPTION FACTOR
+ Binding of transcription factor to gene promoter
SIGNAL PATHWAY
+ Saccharomyces cerevisiae (yeast)
+ Msn2 is TF that binds to DNA stress response element.
+ Stress stimuli: dephosphorylated , enter the nucleus , activate genes.
+ Observe how Msn2 respond to different stress– Glucose limitation– Osmotic stress– Oxidative stress
GLUCOSE LIMITATION
Top row: average of single –cell time traces of Msn2-YFP translocation
Bottom row: representative single cell time traces of Msn2-YFP nuclear translocation
+ Sporadic, heterogeneous translocation burst after the initially relatively uniform nuclea burst.
OSMOTIC STRESS
+ Similarly uniform initial nuclear burst, fewer subsequence sporadic burst
OXIDATIVE STRESS
+ Prolonged nuclear enrichment of Msn2
+ Observe how Msn2 respond to different stress+ What is the gene expression corresponding to
Msn2?– Hill equation– Curve fitting
+ Observe how Msn2 respond to different stress+ What is the gene expression corresponding to
Msn2?+ How dynamical modulation would affect gene
expression– Experiment – Computational model
+ Is it only the Msn2 nuclear localization level and time that matter, or is it influenced by the dynamic profile of Msn2 activation?
+ Area under curve of nuclear trace—max expression
Single pu;se (black blue red)
Oscillatory input (orange)
+ Max expression to Amplitude(change duration), Duration(change amplitude), Frequency
+ Observe how Msn2 respond to different stress+ What is the gene expression corresponding to
Msn2?+ How dynamical modulation would affect gene
expression+ Hypothetical model simulation
– Change parameters in computation model
+ Different TF binding parameter Kd, n, same promoter kinetic
+ AM is sensitive
+ Same binding parameter, different promoter kinetics k1,k2
+ DM and FM are sensitive.
+ All different+ Combines the results
+ Observe how Msn2 respond to different stress+ What is the gene expression corresponding to
Msn2?+ How dynamical modulation would affect gene
expression+ Hypothetical model simulation+ Analysis of a simplified model
SIMPLIFIED MODEL
+ Time scale of promoter transition
