ch 15 gene regulation in eukaryotes i: translational and transcriptional regulation Flashcards
gene regulation
the phenomenon in which the level of gene expression can vary under different conditions
transcription factor
a category of proteins that influence the ability of rna polymerase to transcribe dna into rna
general transcription factor (GTF)
one of several proteins that are necessary to initiate basal transcription at the core promoter
regulatory transcription factor
a protein or protein complex that binds to a regulatory element and influences the rate of transcription via rna polymerase
regulatory sequence
(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
activator
a regulatory protein that binds to dna and increases the rate of transcription
enhancer
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
repressor
a regulatory protein that binds to dna and inhibits transcription
silencer
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
combinatorial control
the phenomenon widely observed in eukaryotes in which the combination of many factors determines the expression of any given gene
domain
a segment of a protein that has a specific function
motif
- in proteins, the name given to an amino acids sequence that has a very similar structure and function to. many proteins
- in dna or rna, the name given to a particular nucleotide base sequence that has a specific function
homodimer
a combined structure (dimer) formed when two polypeptides encoded by the same gene bind to each other
heterodimer
a combined structure (dimer( formed when two polypeptides encoded by different genes bind to each other
up regulation
genetic regulation that leads to an increase in gene expression
down regulation
genetic regulation that leads to a decrease in gene expression
orientation-independent
(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
TFIID
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
coactivator
an activator protein that increases the rate of transcription but does no directly bind to the dna itself
transactivation domain
a domain in a coactivator protein that promotes the activation rna polymerase
mediator
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
steroid receptor
a category of transcription factor that responds to a steroid hormone, which binds directly to it; an example if the glucocorticoid receptor
glucocorticoid receptor
a type of steroid receptor that functions as a regulatory transcription factor
cAMP response element binding (CREB) protein
a regulatory transcription factor that becomes activated in response to specific cell-signaling molecules that cause the synthesis of cAMP
camp response element (CRE)
a short dna sequence found near certain eukaryotic genes that is recognized by the CREB protein
atp-dependent chromatin remodeling
(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
closed conformation
a conformation of chromatin that cannot be transcribed and may be tightly packed
open conformation
a loosely packed structure of chromatin that can be transcribed
dna translocase
a catalytic ATPase subunit that moves along the dna; it is a component of chromatin-remodeling complexes
histone variants
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
histone acetyletransferase
an enzyme that attaches an acetyl group to the amino-terminal tail of a histone protein
histone code hypothesis
the hypothesis that the pattern of histone modification acts much like a language or code in specifying alterations in chromatin structure
chromatin immunoprecipitation sequencing (ChIP-Seq)
a technique that is used to determine where in a genome a particular protein binds to the dna
immunoprecipitation
the use of antibodies to cause other molecules, such as proteins, to precipitate, which allows them to be collected by centrifugation
nucleosome-free region (NFR)
a region within the dna of a eukaryote where nucleosomes are not found
dna methylation
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
dna methyltransferase
the enzyme that attaches a methyl group to cytosine in eukaryotes prokaryotes or to adenine in prokaryotes
CpG island
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
housekeeping gene
a gene that encodes a protein required in most cells of a multicellular organism
tissue-specific gene
a gene that is highly regulated and is expressed only in a particular cell type
methyl-CpG-binding protein
a protein that binds to a CpG island when it is methylated
de novo methylation
the methylation of dna that has not been previously methylated; usually a highly regulated event
maintenance methylation
the methylation of hemimethylated dna following dna methylation
iron regulatory protein (IRP)
a translational regulatory protein that recognizes iron response elements that are found in specific mRNAs; may inhibit translation or stabilize rna
iron response element (IRE)
a sequence in mrnas that is recognized by the iron regulatory protein
