Regulation of Trx

Question 1

When lac operon on

Answer 1

low glucose, high lactose

Question 2

lac operon genes

Answer 2

1. lac operon repressor

2. enzymes used in lactose utilization

Question 3

enzymes use din lactose utlizaion

Answer 3

beta galactosidase, permase, transacetylase

Question 4

when repressor is bound

Answer 4

prevents trx of proteins, binds to operator and streakily blocks lac promoter/sigma subunit

Question 5

allolactose

Answer 5

inducer that binds to repressor so can use lac operon

Question 6

helix turn helix motif

Answer 6

proteins bind to palindromic sequences as dimers (lac repressor, trp repressor, and cap)

Question 7

CAP

Answer 7

binds dna and cAMP -hunger signal

Question 8

CAP-cAMP

Answer 8

positive regulatory factor that is resonsive to glucose levels

Question 9

Lac repressor

Answer 9

CALLED LACI, negative reg factor resposnsive to lactose

Question 10

+glucose/-lactose

Answer 10

CAP not bound to cAMP (adenyl cyclase off), repressor sits in operator, repressor mRNA synthesized (before the operator for the other proteins)

Question 11

-glucose/+lactose

Answer 11

adenyl cyclase on, CAP binds to cAMP, CAP-cAMP bind to another cap binding site (promoter) and activate trx, allolactose binds to repressor to cause conformational change, and operator free, trx of three proteins occur

Question 12

adenyl cyclase

Answer 12

turns off when no glucose-binds CAP to cAMP

Question 13

+glucose/+lactose

Answer 13

adenyl cyclase off, CAP remains unbound, alloctose inhibits the repressor, but cap binding site is empty so no trx DRAW ALL 3 STATES

Question 14

Binding sites

Answer 14

Cap binding site (promoter), repressor binding site

Question 15

Repressor synthesis

Answer 15

always active

Question 16

Agonists vs antagonists

Answer 16

Bind to hormone receptors, stimulate receptor activity/gene expression
vs
bind hormone receptors and block acceptor activity-repress gene expression

Question 17

Structures of steroid receptors

Answer 17

ligand binding domian, DNA binding domain, activation domain

Question 18

Zinc finger

Answer 18

Zn between cystine and histadine, and binds to DNA well

Question 19

Gluccocorticoid/estrongen

Answer 19

17bps palindromic only difference is 4 nucleotides

- recruit bassal TRX factors, and unpack nucleosomes

Question 20

activator specificity

Answer 20

1000’sbps away from TSS, dimeric protein=DNA binding domain, hormone binding domain, and DNA activation domain-unravels the promoter/gene from nucleosome which allows trx to occur

Question 21

Chromatin remodeling

Answer 21

enhancer element binds to steroid hormone receptor, conformational change, recruits coactivator (affects histone tail or loosens up knot), gene will then be exposed
-signalled by hormones

Question 22

Coactivator activity

Answer 22

Catalytic activity-Affect histeone tail-tightens or loosesns knot, or remodeling activity-ATP driven-loosen knot with small motor

Question 23

Trx reg by sterooid hormone receptor

Answer 23

binding of steroid to receptor results in conformational change that uncovers zinc binding domain, Zn domain interacts with GRE complexes, which coupled with other coactivators and complexes bind to promoters and begin gene expression (creates loop)

Question 24

Tamoxafin

Answer 24

binds to estrogen receptor, no conformaitonal change like estrogen makes receptor, not enhancing of trx

Question 25

RNAi

Answer 25

decreases gene expression by resulting in degradation of mRNA

Question 26

IRES

Answer 26

internal ribosome entry site

can have trx start from middle of mRNA