Chapter 17: Expression in Eukaryotes

Question 1

DNAase I hypersensitive site

Answer 1

Chromatin regions of increased sensitivity to DNase I.

Question 2

CpG island

Answer 2

DNA regions with many CpG sequences and are commonly found near transcription sites

Question 3

mediator

Answer 3

Complex of proteins that is one of the components of the basal transcription apparatus

Question 4

super-enhancer

Answer 4

a number of enhancers clustered together that stimulate high levels of transcription

Question 5

insulator

Answer 5

DNA sequence that blocks or “insulates” the effects of enhancers

Question 6

heat-shock protein

Answer 6

inducible; only expressed under certain conditions

Question 7

response element

Answer 7

a specific DNA sequence that binds to regulatory proteins to control gene transcription, acting as a switch that is activated by certain stimuli like hormones or stress. (bind upsteam)
- various proteins may bind to upstream response elements to stimulate transcription

Question 8

SR protein

Answer 8

Serine- and arginine- rich proteins that regulate alternative splicing of pre-mRNA

Question 9

Transcription Activators and Co-activators

Answer 9

stimulate and stabilize basal transcription apparatus at core promotor

Question 10

Gal4 protein

Answer 10

binds to DNA called upstream activation sequence (UAS) to activate gene expression of genes involved in galactose metabolism

Question 11

GAL80

Answer 11

protein binds to GAL4 to stop it from doing its job

Question 12

GAL3

Answer 12

Allowed by galactose to bind to GAL80 to stop it from stopping GAL4

Question 13

Bacterial Vs Eukaryotic Gene Regulation

Answer 13

• each gene has its own promotor and is transcribed independently while bacterial operons have multiple gene with a shared promotor (transcribed together)
• DNA must unwind from the histone proteins before transcription while prokaryotes dont have histones
• Transcription and translation are separated in time and space (RNA transcribed in the nucleus while translation is outside the nucleus), no nucleus prokaryotes means translation can happen simultaneously

Question 14

Chromatin remodeling complexes

Answer 14

reposition the nucleosomes, allowing transcription factors and RNA polymerase to bind to promoters and initiate transcription

Question 15

Acetylation of histones

Answer 15

alters chromatin structure and permits some transcription factors to bind to DNA

Question 16

Gene regulation can be 3 things

Answer 16

1. constitutive
2. inducible
3. tissue-specific

Question 17

Examples of constitutive regulation in eukaryotes

Answer 17

Actin5C , Polyubiquitin , IE-1

Question 18

Examples of inducible regulation in eukaryotes

Answer 18

Heat shock protein 70 (Hsp70)

Question 19

Examples of tissue-specific regulation in eukaryotes

Answer 19

nanos, vasa, B-tubulin

Question 20

Posttranscriptional regulation

Answer 20

the control of gene expression after transcription, affecting the RNA molecule’s processing, stability, and translation into protein

Question 21

Posttranslational regulation

Answer 21

the process of controlling a protein’s function after it has been synthesized through biochemical modifications