regulation of gene expression Flashcards

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1
Q

common themes of gene regulation

A
  1. Genes and regulatory elements (non transcribed DNA) 2. Levels of gene regulation (replication, transcription, translation, etc) 3. DNA-Binding proteins (transcription)
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2
Q

regulatory protein domains

A

the functional part of the protein, binds to DNA

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3
Q

regulatory protein motifs

A

simple structures found in the binding domain that fits into the major groove of DNA

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4
Q

What level does most regulation occur at in bacteria?

A

transcription

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5
Q

operon (bacteria)

A

transcriptional unit consists of promoter + operator + structural genes

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6
Q

where can E. coli be found?

A

in our large intestines

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7
Q

what is in the lac operon?

A

promoter lacP, operator lacO, structural genes lacZ, lacY, and lacA

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8
Q

how is lac operon controlled?

A

negative control. in absence of lactose it is repressed and does not transcribe.

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9
Q

is the repressor protein gene lacI part of the operon?

A

no. it has its own promoter and is located away from the operon

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10
Q

how does the lac operon repressor work?

A

in the absence of lactose the repressor binds to the operator and represses transcription. in the presence of lactose, allolactose will bind to repressor and it will release from operator

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11
Q

partial diploid

A

full bacterial chromosome + an extra piece of DNA on F plasmid

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12
Q

lacZ+

A

functional, produces B-galactosidase

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13
Q

lacZ-

A

nonfunctional, produces defective B-galactosidase

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14
Q

lacY+

A

functional, produces permease

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15
Q

lacY-

A

nonfunctional, produces defective permease

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16
Q

lacI+

A

functional, produces repressor

17
Q

lacI-

A

nonfunctional, produces defective non binding repressor

18
Q

lacIs

A

superreppressor, cannot be deactivated

19
Q

lacO+

A

functional, repressor can bind normally

20
Q

lacOc

A

nonfunctional, repressor cannot bind

21
Q

lacP+

A

functional promotor

22
Q

lacP-

A

nonfunctional promoter

23
Q

cis mutations

A

operator, promoter, structural

24
Q

trans mutations

A

regulator

25
Q

catabolite activator protein (CAP) and cAMP

A

cAMP binds to CAP, complex binds to a site upstream from lac promoter, bends, and enhances the binding of RNA polymerase. positive control, low glucose means increased cAMP

26
Q

eukaryote operon?

A

no. each gene has its own promoter and transcribed separately

27
Q

chromatin remodeling

A

chromatin remodeling complexes alter chromatic structure and reposition nucleosomes (sliding or conformational changes)

28
Q

histone modification

A

two domains: globular and tail. Tail can be modified by phosphate groups, methyl groups, and acetyl groups

29
Q

Arabidopsis flowering control

A

histone modification stimulates flowering by repressing the FLC gene (removes acetyl groups from chromatin surrounding FLC)

30
Q

DNA methylation

A

methyl groups added to cytosine bases adjacent to guanine nucleotides (CpG islands). often at the start of a gene, removed before initiation. also distinguishes parent strands of DNA

31
Q

Enhancers/Activators

A

regulatory elements that affect transcription rate of distant genes. contain consensus sequence binding sites for transcriptional activator proteins. proteins that bind can act through coactivators to indirectly interact with basal transcription apparatus or interact directly

32
Q

Insulators

A

block enhancers from reaching promoters.

33
Q

Repressors/Silencers

A

can compete with activators for the same sequence, bind to the activator protein domain so it can’t function, and directly interact with transcription factors to block further assembly

34
Q

coordinated gene regulation

A

genes can have the same regulatory sequences associated with them, so a single trigger can regulate many different genes (response elements)

35
Q

mRNA degredation

A

the amount of protein synthesized is dependent on the amount of mRNA available for translation, availability is due to how much is produced and how long it lasts. poly-A tail is shortened, 5’ cap removal, nucleases remove nucleotides from 5’ end.