Gene Regulation Flashcards
What are the 2 levels of cell regulation?
- Controling the activity of preexisting enzymes/proteins
- Postranslational regulation - rapid response
- Controlling the amount of an enzyme/protein
- regulate levels of transcription and translation
- Slower process (minutes)
DNA Binding Proteins
- Bind DNA in a []-specific manner
- Specificity of amino acid side chains towards [] - [] backbone of DNA
- [] groove of DNA is main site of protein binding
- [] repeats frequently are binding sites for homodimeric regulatory proteins
- sequence-specific
- sugar-phosphate
- Major groove
- Inverted repeats
3 major possibilities of DNA Binding Proteins actually binding?
- Binding event can block transcription (negative)
- Binding event can activate transcription (positive)
- Nothing could happen if full complement of protines not present
What portion of the promoter region does a repressor (w/o its co-repressory) block?
Operator
What is “induction” in gene regulation??
- Removal of repression by inducers
Positive control of transcriptions is….?
- regulator protein activates the binding of RNA polymerase to DNA
Activator protiens usually bind specifically to certain DNA sequences called - [] ?
- Activator Binding sites
- not an operator
Activation Details
- Promoters of positively controlled operons [] bind RNA Polymerase
- Activators help RNA Pol recognize []
- May cause change in [] structure
- May interact directly with []
- Activator binding site may be [] to promoter or several [] base pairs away
- weakly
- Promoters
- DNA
- RNA Pol
- Close to or several hundred base pairs away
Do regulons exist for negatively controlled systems?
Yes
Transcription factors that regulate many promoters and have large regulons exhibit “ [] “
Global Control
What is the activator for the lac operon?
What is its co-activator?
What is its repressor?
What is its inducer?
- Cyclic AMP receptor protein (CRP)
- Cyclic AMP - co activator
- LacI - repressor
- Lactose is inducer
Which co-activator molecule is made in the absence of glucose?
cAMP
What are the 4 ways that transcriptional control is dictated by the intra/intercellular signaling?
- 2 component System
- Quorum sensing
- Stringent Response
- Heat Shock
What are the 2 components in a signal transduction regulatory system?
Sensor Kinase (H)
Response Regulator (D)
What is Quorum sensing in bacteria?
How does it work?
- Means to assess population in a local environment
- Production of small QS molecule accumulates in extracellular milieu
- signal receptors receive the signal and translate it into a new gene expression
- Can effect - biofilm formation, light production, motility etc