ch 15 gene regulation in eukaryotes i: translational and transcriptional regulation

Question 1

gene regulation

Answer 1

the phenomenon in which the level of gene expression can vary under different conditions

Question 2

transcription factor

Answer 2

a category of proteins that influence the ability of rna polymerase to transcribe dna into rna

Question 3

general transcription factor (GTF)

Answer 3

one of several proteins that are necessary to initiate basal transcription at the core promoter

Question 4

regulatory transcription factor

Answer 4

a protein or protein complex that binds to a regulatory element and influences the rate of transcription via rna polymerase

Question 5

regulatory sequence

Answer 5

(also called control element or regulatory element) a segment of dna that is recognized by a regulatory transcription factor; the binding of the transcription factor affects the rate of transcription

Question 6

activator

Answer 6

a regulatory protein that binds to dna and increases the rate of transcription

Question 7

enhancer

Answer 7

a dna sequence that functions as a regulatory element in eukaryotes; the binding of a regulatory transcription factor to an enhancer increases the rate of transcription

Question 8

repressor

Answer 8

a regulatory protein that binds to dna and inhibits transcription

Question 9

silencer

Answer 9

a dna sequence that functions as a regulatory element in eukaryotes; the binding of a regulatory transcription factor to a silencer decreases the rate of transcription

Question 10

combinatorial control

Answer 10

the phenomenon widely observed in eukaryotes in which the combination of many factors determines the expression of any given gene

Question 11

domain

Answer 11

a segment of a protein that has a specific function

Question 12

motif

Answer 12

1. in proteins, the name given to an amino acids sequence that has a very similar structure and function to. many proteins
2. in dna or rna, the name given to a particular nucleotide base sequence that has a specific function

Question 13

homodimer

Answer 13

a combined structure (dimer) formed when two polypeptides encoded by the same gene bind to each other

Question 14

heterodimer

Answer 14

a combined structure (dimer( formed when two polypeptides encoded by different genes bind to each other

Question 15

up regulation

Answer 15

genetic regulation that leads to an increase in gene expression

Question 16

down regulation

Answer 16

genetic regulation that leads to a decrease in gene expression

Question 17

orientation-independent

Answer 17

(also called bidirectional) refers to certain types of genetic regulatory elements that can function in the forward or reverse direction; certain enhancers are orientation-independent

Question 18

TFIID

Answer 18

a type of general transcription factor in eukaryotes that is needed for rna polymerase ii function; it binds to the tata box and recruits rna polymerase ii to the core promoter

Question 19

coactivator

Answer 19

an activator protein that increases the rate of transcription but does no directly bind to the dna itself

Question 20

transactivation domain

Answer 20

a domain in a coactivator protein that promotes the activation rna polymerase

Question 21

mediator

Answer 21

a large protein complex that interacts with rna polymerase ii and various regulatory transcription factors; depending on interactions with regulatory transcription factors, mediator may stimulate or inhibit rna polymerase ii

Question 22

steroid receptor

Answer 22

a category of transcription factor that responds to a steroid hormone, which binds directly to it; an example if the glucocorticoid receptor

Question 23

glucocorticoid receptor

Answer 23

a type of steroid receptor that functions as a regulatory transcription factor

Question 24

cAMP response element binding (CREB) protein

Answer 24

a regulatory transcription factor that becomes activated in response to specific cell-signaling molecules that cause the synthesis of cAMP

Question 25

camp response element (CRE)

Answer 25

a short dna sequence found near certain eukaryotic genes that is recognized by the CREB protein

Question 26

atp-dependent chromatin remodeling

Answer 26

(also called chromatic remodeling) changes in chromatic structure that are due to the action of chromatin-remodeling complexes and affect the positions and/or compositions of nucleosomes

Question 27

closed conformation

Answer 27

a conformation of chromatin that cannot be transcribed and may be tightly packed

Question 28

open conformation

Answer 28

a loosely packed structure of chromatin that can be transcribed

Question 29

dna translocase

Answer 29

a catalytic ATPase subunit that moves along the dna; it is a component of chromatin-remodeling complexes

Question 30

histone variants

Answer 30

histone proteins whose amino acid sequences are slightly different from those of the standard histones; they often play specialized roles in chromatin structure and function

Question 31

histone acetyletransferase

Answer 31

an enzyme that attaches an acetyl group to the amino-terminal tail of a histone protein

Question 32

histone code hypothesis

Answer 32

the hypothesis that the pattern of histone modification acts much like a language or code in specifying alterations in chromatin structure

Question 33

chromatin immunoprecipitation sequencing (ChIP-Seq)

Answer 33

a technique that is used to determine where in a genome a particular protein binds to the dna

Question 34

immunoprecipitation

Answer 34

the use of antibodies to cause other molecules, such as proteins, to precipitate, which allows them to be collected by centrifugation

Question 35

nucleosome-free region (NFR)

Answer 35

a region within the dna of a eukaryote where nucleosomes are not found

Question 36

dna methylation

Answer 36

a regulatory mechanism in which an enzyme covalently attaches a methyl group (–CH3) to a base in dna; in eukaryotes, the base is cytosine; in prokaryotes, both adenine and cytosine can be methylated

Question 37

dna methyltransferase

Answer 37

the enzyme that attaches a methyl group to cytosine in eukaryotes prokaryotes or to adenine in prokaryotes

Question 38

CpG island

Answer 38

a group of CG base sequences that may be clustered near a promoter region of a gene; the methylation of cytosine bases usually inhibits transcription

Question 39

housekeeping gene

Answer 39

a gene that encodes a protein required in most cells of a multicellular organism

Question 40

tissue-specific gene

Answer 40

a gene that is highly regulated and is expressed only in a particular cell type

Question 41

methyl-CpG-binding protein

Answer 41

a protein that binds to a CpG island when it is methylated

Question 42

de novo methylation

Answer 42

the methylation of dna that has not been previously methylated; usually a highly regulated event

Question 43

maintenance methylation

Answer 43

the methylation of hemimethylated dna following dna methylation

Question 44

iron regulatory protein (IRP)

Answer 44

a translational regulatory protein that recognizes iron response elements that are found in specific mRNAs; may inhibit translation or stabilize rna

Question 45

iron response element (IRE)

Answer 45

a sequence in mrnas that is recognized by the iron regulatory protein