Control of Gene Expression

Question 1

Housekeeping genes

Answer 1

genes expressed in all cells because they provide basic functions needed for sustenance of all cells

Question 2

global regulatory mechanisms

Answer 2

not specific for a given gene, affect expression of many genes, example: methylation

Question 3

nucleosome

Answer 3

comprised of histones, helps to tightly pack DNA, binding makes DNA inaccessible

Question 4

heterochromatin

Answer 4

transcriptionally inactive DNA, not accessible to DNase

Question 5

Euchromatin

Answer 5

transcriptionally active DNA, accessible to DNase

Question 6

Hypersensitive sites

Answer 6

sections of chromatin that are very sensitive to DNase

Question 7

Locus Control Regions (LCR)

Answer 7

Regulate chromatin organization over chromosomal domains

Question 8

SWI-SNF protein complex

Answer 8

can alter chromatin structure and remodel nucleosomes, can act globally or specifically

Question 9

Histone acetylation

Answer 9

leads to the unfolding of chromatin, increasing accessibility of DNA

Question 10

DNA methylation

Answer 10

associated with diminished gene expression, important in X-inactivation

Question 11

DNA methyltransferase

Answer 11

Adds a methyl group to CpG dinucleotides

Question 12

CpG islands

Answer 12

long CpG rich stretches of DNA in promoter regions, actively transcribed in all cells, lack methylation

Question 13

activator

Answer 13

bind to regulatory regions (enhancers), to facilitate transcription

Question 14

coactivators

Answer 14

help the activators communicate with other basal transcription factors

Question 15

inducible gene expression

Answer 15

allows for the right gene to be activated in the right cell

Question 16

HSF (heat shock factor)

Answer 16

present in cells, only binds to DNA under heat shock, initiating transcription (example of inducible gene expression)

Question 17

intracellular steroid receptor

Answer 17

Binds to steroid in the cytoplasm, complex transports to nucleus and activates transcription (displaces nucleosomes from promoter)

Question 18

response elements

Answer 18

also known as enhancers - binding site on DNA for hormone steroid receptor complex

Question 19

microarray

Answer 19

technique used to determine differences in the mRNA population between two cell types

Question 20

RNA-Seq

Answer 20

new method to determine composition and quantity of RNA present in a cell, uses next generation sequencing

Question 21

Antisense Therapy

Answer 21

Introduce nucleic acid complementary to mRNA, blocking translation, largely experimental

Question 22

RNA interference (RNAi)

Answer 22

targeted destruction of a particular mRNA via complementarity to double-stranded RNA activators