Chapter 14: Gene Regulation In Eukaryotes Flashcards
genes that code for proteins have promoters that contain
transcriptional start site
TATA Box
regulatory elements
transcriptional start site
+1
place where RNA synthesis begins
TATA Box
position
binding
sequence in the promoter -25 bases from start site
position of TATA box determines where RNA synthesis starts
general transcription factors and RNA polymerase bind
core promoter
TATA Box and start site
genes that have only a core promoter have
Low (basal) level of transcription
(Core promoter has bare minimum for what is needed to make RNA)
regulatory elements
DNA sequences that regulate the expression of genes
usually located -50 to -100 bases from start site
if ____ bind to the regulatory elements of a gene transcription levels of the gene are greatly ____
transcription factors (activators)
increased
in eukaryotes, transcription factors are
activators
eukaryotes don’t have
operons
all genes expressed at the same time have
same regulatory element sequences in promoter
transcription factors (activators) bind to the regulatory elements
the genes are transcribed
coordinate gene expression
genes that have the same regulatory element in their promoter will be expressed at the same time
SRE
DNA sequence and binding site for TF
how are genes that code for proteins in the same pathway coordinately regulated?
Coordinate expression of nonadjacent genes
genes on different t parts of a chromosome have the same DNA response element in their promoter
genes activated by the same stimulus have same ___ in their ___
DNA response element
promoters
one gene may be regulated by
many different response elements
metallothionein
turned
stress response gene
turned on by heavy metals, steroids, other stress
eukaryotic genes have many
enhancers
enhancers
DNA sequences located far away from the start site of a gene, that regulate transcription from the gene
-1000s
only found in eukaryotes
only found in prokaryotes
enhancers
operons
number of bases
core promoter
regulatory elements
enhancers
+1 to -30
-50 to -100
-1000s
activator proteins
bind to sequences (regulatory elements) in the enhancer
transcription factor
mediator proteins
bind to the activator proteins and form a large complex
The DNA bends so now
the enhancer is located near the promoter of the gene
general transcription factors bind to
which leads to
the activators and the promoter
rna polymerase binding-> high level of RNA made
tissue specific gene regulation
every cell has the same DNA
different tissues make different rna and proteins
liver cell produces
album protein found in blood
lens cell of eye produces
crystallin protein
genes expressed in a specific tissue have a unique set of
regulatory elements in their enhancers
specific activator proteins bind
to each regulatory elements (dna sequences)
different activator proteins are expressed in
different cell types
The specific transcription factors/ activators made in each cell type determines
which genes are expressdd
regulation of chromatin structure
DNA needs to be in the less condensed, unwound form (beads on a string, 10nm) to be transcribed into RNA
tightly packed means proteins can’t get through and bind.
chromatin has ___ forms
they are
2
euchromatin and heterochromatin
euchromatin
less condensed form of DNA
beads on a string, 10 nm
genes can be expressed
heterocromatin
more condensed form of DNA
30 nm or more compact
genes are usually off
genes must be in the ___ condensed form of chromatin to be expressed
less
activator proteins bind to both
the enhancers and regulatory elements
the genes in euchromatin are turned
heterochromatin
on
off
three ways to change chromatin structure
acetylation of histones
chromatin remodeling
methylation of DNA in promoter
histone code
additional if certain groups to histones in nucleosomes controls whether DNA is tightly wound up or in less condensed form
chromatin remodeling
some of the nucleosomes are removed and DNA is partially unwound
what changes are in euchromatin, turns genes on
acetylation of histones
chromatin remodeling
what changes are in heterochromatin and turn genes off
methylation of DNA in promoter
methylation of DNA in promoter
prevents transcription factors from binding to DNA and causes DNA to tightly wind up
easiest way to turn DNA off is
methylation of DNA in promoter
active
silent
euchromatin
heterochromatin
