Gene Regulation Flashcards

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1
Q

What are the 2 levels of cell regulation?

A
  1. Controling the activity of preexisting enzymes/proteins
    1. Postranslational regulation - rapid response
  2. Controlling the amount of an enzyme/protein
    1. regulate levels of transcription and translation
    2. Slower process (minutes)
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2
Q

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
A
  1. sequence-specific
  2. sugar-phosphate
  3. Major groove
  4. Inverted repeats
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3
Q

3 major possibilities of DNA Binding Proteins actually binding?

A
  1. Binding event can block transcription (negative)
  2. Binding event can activate transcription (positive)
  3. Nothing could happen if full complement of protines not present
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4
Q

What portion of the promoter region does a repressor (w/o its co-repressory) block?

A

Operator

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5
Q

What is “induction” in gene regulation??

A
  • Removal of repression by inducers
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6
Q

Positive control of transcriptions is….?

A
  • regulator protein activates the binding of RNA polymerase to DNA
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7
Q

Activator protiens usually bind specifically to certain DNA sequences called - [] ?

A
  • Activator Binding sites
    • not an operator
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8
Q

Activation Details

  1. Promoters of positively controlled operons [] bind RNA Polymerase
  2. Activators help RNA Pol recognize []
    1. May cause change in [] structure
    2. May interact directly with []
  3. Activator binding site may be [] to promoter or several [] base pairs away
A
  1. weakly
  2. Promoters
    1. DNA
    2. RNA Pol
  3. Close to or several hundred base pairs away
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9
Q

Do regulons exist for negatively controlled systems?

A

Yes

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10
Q

Transcription factors that regulate many promoters and have large regulons exhibit “ [] “

A

Global Control

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11
Q

What is the activator for the lac operon?

What is its co-activator?

What is its repressor?

What is its inducer?

A
  • Cyclic AMP receptor protein (CRP)
  • Cyclic AMP - co activator
  • LacI - repressor
  • Lactose is inducer
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12
Q

Which co-activator molecule is made in the absence of glucose?

A

cAMP

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13
Q

What are the 4 ways that transcriptional control is dictated by the intra/intercellular signaling?

A
  1. 2 component System
  2. Quorum sensing
  3. Stringent Response
  4. Heat Shock
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14
Q

What are the 2 components in a signal transduction regulatory system?

A

Sensor Kinase (H)

Response Regulator (D)

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15
Q

What is Quorum sensing in bacteria?

How does it work?

A
  • 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
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16
Q
  1. What is the stringent response of bacteria?
  2. What is it triggered by?
A
  1. global control mechanism triggered by amino acid starvation
    1. achieves balance between protein production and protein catabolism
  2. Triggered by (p)ppGpp
    1. Alarmones - produces by ReIA to signal amino acid starvation
    2. rRNA and tRNA syn decreases
17
Q

What are the 4 types of RNA based regulation?

A
  1. Antisense RNA
  2. Riboswitches
  3. Attenuation
  4. CRISPR
18
Q

Do antisense RNAs act positively or negatively on RNA?

A

Both!

  • Positively by preventing secondary structures from forming or exposing robosome bind site
  • Negatively by base pairing with ribosome binding site to prevent ranslation or elongation
19
Q

What is a riboswitch?

A
  • RNA domain within an mRNA molecule that can bind small molecules to control translation of mRNA
  • located at 5’ end
  • binding leads to a folded RNA
20
Q

What is attenuation in RNA-based regulation?

A
  • premature termination of mRNA synthesis