Gene Regulation

Front 1

What operons are regulated by Attenuation?

Back 1

Threonine, Phenylalanine, Histidine, Tryptophan

Front 2

What is the regulation strategy for Bacterial lactose operon?

Back 2

Gene regulation by inducer, repressor protein, and activator protein in the lac operon

Front 3

What is the regulation strategy for Bacterial tryptophan operon?

Back 3

Repressor, ribosome and mRNA structure regulation transcription

Front 4

What is the regulation strateg of Phage Lambda repressor?

Back 4

Gene regulation through different binding strengths of repressor to DNA sequence motifs

Front 5

What do genes in a common operon share?

Back 5

A promotor and are responsive to common repressor and activator proteins.

Front 6

What is positive regulation?

Back 6

Transcription of a gene is increased by presence of specific activator (or by inactive of repressor)

Front 7

What is negative regulation?

Back 7

Transcription of a gene is decreased by presence of a repressor (or inactivation of activator)

Front 8

What is a cis acting elements?

Back 8

Cis - sequence of NA that affects activity of adjacent sequences. DNA does not encode a protein. (repressor binding to a site upstream of operator)

Front 9

What is a trans acting elements?

Back 9

This refers to a diffusible product that affects activity of DNA. (Repressor binding to an operator)

Front 10

Where does the lac repressor protein bind?

Back 10

Between the common promoter and 5' end of the 1st gene

Front 11

What regulates whether CAP can bind to the lac promotor?

Back 11

levels of cAMP. cAMP binds to CAP and enables it to fit into the major groove of DNA.

Front 12

What functional domains does CAP have?

Back 12

ligand binding, DNA binding, and protein-protein interaction

Front 13

What are the functional subdomains on the lac repressor?

Back 13

ligand, DNA binding, protein-protein interaction. It binds as a dimer to a palindromic sequence of the operator DNA

Front 14

What regulates whether CAP can bind to the lac promotor?

Back 14

levels of cAMP. cAMP binds to CAP and enables it to fit into the major groove of DNA.

Front 15

What are the two mechanisms by which tryptophan is regulated?

Back 15

1. The Trp repressor binding to the operator sequence

2. Attentuation -trp levels modify RNA structure to form a transcriptional terminator or an anti-terminator

Front 16

What functional domains does CAP have?

Back 16

ligand binding, DNA binding, and protein-protein interaction

Front 17

What is the structure of the attenuation terminator?

Back 17

G-C stem followed by poly U's.

Front 18

What are the functional subdomains on the lac repressor?

Back 18

ligand, DNA binding, protein-protein interaction. It binds as a dimer to a palindromic sequence of the operator DNA

Front 19

How does the Phage lambda repressor work? (general mechanism)

Back 19

Through different binding strengths of the lambda repressor to the operator DNA sequence

Front 20

What are the two mechanisms by which tryptophan is regulated?

Back 20

1. The Trp repressor binding to the operator sequence

2. Attentuation -trp levels modify RNA structure to form a transcriptional terminator or an anti-terminator

Front 21

Is the phage lambda repressor an example of Auto-regulation?

Back 21

YES! cl and cro activator genes share a common operator.

Front 22

What is the structure of the attenuation terminator?

Back 22

G-C stem followed by poly U's.

Front 23

What are constitutive enzymes?

Back 23

Enzymes that are synthesized at more or less a constant rate

Front 24

How does the Phage lambda repressor work? (general mechanism)

Back 24

Through different binding strengths of the lambda repressor to the operator DNA sequence

Front 25

What are inducible enzymes?

Back 25

enzymes that are synthesized depending on need and in response to cellular cues

Front 26

Is the phage lambda repressor an example of Auto-regulation?

Back 26

YES! cl and cro activator genes share a common operator.

Front 27

What 3 enzymes are translated in the lac operon?

Back 27

b-galactosidase, permease, transacetylase

Front 28

What are constitutive enzymes?

Back 28

Enzymes that are synthesized at more or less a constant rate

Front 29

What are inducible enzymes?

Back 29

enzymes that are synthesized depending on need and in response to cellular cues

Front 30

What 3 enzymes are translated in the lac operon?

Back 30

b-galactosidase, permease, transacetylase

Front 31

What would occur if the lacl repressor gene is deleted?

Back 31

Transcription will always be turned on

Front 32

What happens to CAP when there is low glucose and high lactose?

Back 32

If there is low glucose, AC produces more cAMP, cAMP binds to CAP activating the lac operon

Front 33

What is an insulator?

Back 33

An area that prevents the enhance of a gene domain to be activated by genes in neighboring domains.

Front 34

What is a eukaryotic enhancer/promotor?

Back 34

DNA sequence that bind tissue specific and constitutive transcription factor proteins

Front 35

What binds to a eukaryotic ligand binding domain?

Back 35

inducers, repressors, hormones

Front 36

What binds to a eukaryotic activating domain?

Back 36

other transcription factors and RNA polymerase II

Front 37

What binds to eukaryotic DNA binding domain?

Back 37

specific DNA motifs in the promoters, enhancers, and LCRs

Front 38

What is a helix-turn-helix homeodomain?

Back 38

It is a homeotic protein that shares a DNA binding domain. Two alpha helices separated by a tight turn interact with DNA in major groove. CAP, lac, and tryp repressors of E coli through this

Front 39

Basic-leucine zipper (bZIP)

Back 39

There is a leu every 7 bp or so. the Leu form a zipper and bind to sit more tightly (palindromic).

Front 40

What is a helix-loop-helix (bHLH)?

Back 40

A dimeric transcription factor with alpha helices. binds to site... etc

Front 41

What is a zinc motif?

Back 41

It is a motif that spans 30 or so amino acids that are held in a finger arrangement through a Zn coordination. Two form a dimer

Front 42

Does a hormone bind to a receptor on the PM?

Back 42

No, the steroid hormone diffuses into the cytoplasm and then into nucleus. They then bind to zinc fingers in hormone responsive genes.

Front 43

Does a steroid hormone require a transporter?

Back 43

NO

Front 44

What are the steps in steroid hormone regulation?

Back 44

1. Steroid diffuses into cytoplasm.
2. Hormone binds to receptor and translocates into nucleus.
3. The hormone receptor (zinc finger transcription factor) binds to DNA sequence and stimulates transcription.

Front 45

What are the 4 domains of the zinc finger?

Back 45

DNA binding, Dimerization, protein-protein interaction, and ligand binding domain

Front 46

What is great about Class II hormone heterodimers?

Back 46

Transcription of one gene can be turned on and another off in response to the same hormone.

Front 47

What are the sites fo epigenetic modifications on histones?

Back 47

The Amino terminal tails that stuck out from the nucleosome

Front 48

What does methylated DNA do?

Back 48

It recruits HDACS and other co-repressor proteins to close down the chromatin structure and repress transcription

Front 49

What is the Beckwidth-Wiedmann syndrome?

Back 49

Some genes are turned on and off based on whether they are from the mother/father. This is a mutation that leads to abnormal activation of the maternal growth gene.

Front 50

Burkitt's Lymphoma

Back 50

Dysregulation of transcription factors due to chromosome translocations

Front 51

What is Wilms' tumor?

Back 51

It is a childhood malignant kidney cancer resulting from a mutation in the WT1 gene. WT1 codes for a zinc finger TF with 4 zinc fingers

Front 52

Burkitt's lymphoma

Back 52

Translocation of a TF to an immunoglubulin IgH. IgH activates c-myc genes in beta cells. The translocation is the c-myc located on chromosome 8 to chromosome 14 near heavy chain.