Regulation of Transcription Initiation (9)

Question 1

Many activator proteins also bind to a …… which helps RNA polymerase bind to the promoter.

Answer 1

Meidator

Question 2

What are cis regulatory elements?

Answer 2

DNA sequences forming part of a gene involved in its regulation

Question 3

What may cis regulatory elements do?

Answer 3

1) Increase or decrease basal level expression

2) Specify responses to particular signals- response elements (are cis-regulatory elements)

Question 4

An example of a cis regulatory element is..

Answer 4

The human metallothionein gene

Question 5

What are the two functions of Metallothioneins

Answer 5

1) Bind toxic metal ions and so protect organisms from their effects
2) Store needed metal ions such as Zn2+

Question 6

In humans transcription of the metallothieonein gene is induced by what?

Answer 6

Metal ions and glucocorticoid receptor; acting independently of each other.

Question 7

What cis regulatory elements are involved in human metallothionein gene and its transcription?

Answer 7

.TATA
.GC
.BLE
.TRE
.E-box

Question 8

What are the response elements involved in human metallothionein gene and its transcription?

Answer 8

MRE- responds to metals

GRE- responds to glucocorticoid

Question 9

Each cis-regulatory element binds to activator proteins, what are the activator proteins for the human metallothionein gene?

Answer 9

AP2 binds to BLE
AP1 binds to TRE
SP1 binds to the GC box
MTF1 binds to MRE -when activated by binding Zn2+
Glucocorticoid receptor binds to GRE when activated by binding glucocorticoid hormone

Question 10

What are the features of the B-globin gene?

Answer 10

.Multiple binding sites for GATA-1
.Cis-regulatory elements are far downstream of the gene
.Some GATA-1 binding sites overlap with binding sites of other regulatory elements.

Question 11

What does the core promoter do?

Answer 11

Defines where RNA polymerase binds.

Question 12

What is the proximal promoter?

Answer 12

A region near the core promoter

Question 13

What are enhancers?

Answer 13

Cis-regulatory elements far from the core promoter

Question 14

Cis-regulatory elements are recogniseable by there similarity to what sequence?

Answer 14

The consensus sequence

Question 15

What are consensus sequences?

Answer 15

Consensus sequences are recognition sites for particular activator or repressor proteins that bind specifically to this sequence. More than one protein may bind to a single element, these proteins may alter chromatin structure or interact with the transcription complex to change binding of RNA polymerase to promoter.

Question 16

A single type of cis-regulatory element can be found

Answer 16

1) In multiple copies in a single gene

2) In more than one gene

Question 17

Transcription is regulated by

Answer 17

The combination of activator and repressor proteins that bind to cis-regulatory elements. Combinations of activator proteins can increase transcription as much as 10 fold.

Question 18

Elements whose position is not critical are called what?

Answer 18

Enhancers

Question 19

What hormones bind to receptors on the outside of the cell and exert their effect indirectly?

Answer 19

Peptide hormones

Question 20

What is the most important second messenger for peptide hormones?

Answer 20

cyclic AMP

Question 21

What is the principal glucocorticoid hormone?

Answer 21

Cortisol

Question 22

Cortisol is released during….

Answer 22

Starvation or intense excersise

Question 23

What are the physiological effects of cortisol?

Answer 23

• increases blood sugar

- Anti inflammatory and immunosuppressive action

Question 24

Different naturally occurring mutations in the glucocorticoid receptor are associated with?

Answer 24

.Raised BMI

.Beneficial body composition in young adults and greater muscle strength in young men

Question 25

In the liver cells cortisol INCREASES GLUCOSE PRODUCTION by what?

Answer 25

Gluconeogenesis from amino acids

Question 26

Receptors for steriod hormones, thyroid hormones and retinoic acid constitute super family of what?

Answer 26

Ligand-responsive transcription factors

Question 27

What do ligand responsive transcription factors do?

Answer 27

.bind to DNA
.interact with transcription complex to regulate transcription
.made up of domains with distinct functions