Lecture 17: Control of Gene Expression

Question 1

Structural genes

Answer 1

Encoding proteins

Question 2

Regulatory genes

Answer 2

Encode products that interact with other sequences and affect the transcription/translation of them

Question 3

Regulatory elements

Answer 3

DNA sequences that are not transcribed but play a role in regulating other sequences

Question 4

DNA binding domain

Answer 4

60-90 AAs, responsible for forming hydrogen bonds with and binding DNA

Question 5

DNA binding motif

Answer 5

Within the DNA binding domain, a simple structure that fits into the major groove of DNA

Question 6

Operon

Answer 6

Promotor + additional sequences that control transcription (operator) + structural genes

Question 7

DNAse I hypersensitivity sites

Answer 7

More open chromatin configuration, upstream of transcription start site
-include many types of regulatory elements (promotors, enhancers, etc..)

Question 8

ChIP is used to

Answer 8

Identify DNA-binding sites of a specific protein and the locations of modified histone proteins

Question 9

ChIP process

Answer 9

DNA-protein complexes are created, DNA is broken up and the appropriate antibody is used to bind the protein in question. The DNA bound to that protein is sequenced

Question 10

Mediator

Answer 10

Main function is to transmit signals from the transcription factors to the polymerase

Question 11

GAL4

Answer 11

Transcriptional activator protein that activated transcription of galactose. It is inhibited by GAL80 In the absence of galactose

Question 12

Enhancer

Answer 12

DNA sequence stimulating transcription a distance away from promoter

Question 13

Insulator

Answer 13

DNA sequence that blocks or insulates the effect of enhancers (it lies b/w enhancer and promotor)

Question 14

Most transcriptional activator proteins affect transcription by interacting with

Answer 14

The basal transcription apparatus

Question 15

SF2 protein alternative splicing

Answer 15

SF2 protein enhances the use of the second splice site producing an mRNA that encodes the small T antigen

Question 16

PKM2 splice isoform

Answer 16

Aberrantly upregulated in tumor cells for a metabolic switch favoring aerobic glycolysis which creates energy need for tumor growth

Question 17

DICER/RISC and siRNA

Answer 17

DS RNA is cleaved by dicer to produce siRNAs
siRNAs pair with protein to form a RISC, and then pair with complementary sequences on mRNA - RNA is cleaved and degraded

Question 18

DICER/RISC and miRNA

Answer 18

DS RNA cleaved by DICER to form miRNAs

miRNAs join other proteins forming RISC, and imperfectly pair with mRNA- which leads to inhibition of translation

Question 19

siRNA and gene silencing

Answer 19

Some siRNAs bind complementary sequences and attract methylating enzymes which silence the gene

Question 20

Where do miRNAs and siRNAs typically bind mRNA

Answer 20

On the 3’ UTR