BY 210- Genetics Exam 3
1. enhancers: regions of the DNA that interact with regulatory proteins to stimulate
transcription of nearby genes
-can be located upstream, downstream, or within a gene it regulates
2. basal transcription apparatus diagram:
3. silencers: control regions of DNA
-when TFs bind to a silencer, gene expression is repressed
-may be located thousands of bps away from gene they control
4. insulators: stretch of DNA (~42bps) that form a genetic boundary element that blocks
the interaction between enhancers/silencers and promoters
-function: to prevent a gene from being influenced by the activation or repression of its
neighbors
5. transcription factors: binds DNA and stimulate transcriptions
-many different kinds (ex. OCT, CAAT, GC, etc)
6. regulatory proteins: bind to specific DNA regions within the promoter
7. some single nucleotide substitutions can affect the levels of ______________:
transcription
8. dimerization domain: specialized for polypeptide interactions
-homodimers and heterodimers
9. homodimer: multimeric proteins made of identical subunits
10. heterodimer: multimeric proteins made of non-identical subunits
11. transcriptional _________ interact with each other to create novel
specificities-
,: regulators
-homo/heterodimers can regulate different strands because they have new specifications
12. repressor proteins: suppress transcription initiation by recruiting co-repressors
13. what are 2 functions of co-repressors: -repressors can recruit co-repressors
that prohibits RNA pol machinery to associate with the promoter
-repressors can recruit co-repressors that close chromatin
14. _________ can be active or passive: repressors
15 describe active v passive repressors: active- repressor bound to dimer to stop
transcription passive- half of dimer interacts with a protein that prevents it from binding
to DNA
16. what 4 ways can indirect repression operate:
1) competition due to overlapping binding sites
2) Quenching- repressor binds to activation domain
3) Cytoplasmic Sequestration- binding to activator and keeping it in cytoplasm
4) Heterodimerization- binding to activator and preventing homodimerization
17. describe the Wnt signaling pathway: seecreted glycoprotein that binds to a
ligand to regulate growth control and tissue patterning
-in the absence of Wnt, B-catenin is degraded; integration with Gro and TCF makes the
transcription factor act as a repressor
-in the presence of Wnt, B-cantenin is translocated to the nucleus; Gro is ubiquinated;
combo of B-cat and XIAP make
TCF act as an activator
18. how do steroid hormones regulate gene expression: the steroid hormone
will enter its target cell and will bind to a protein molecule
, the hormone receptor complex binds to a hormone response element
the transcript is processed and is transported to the cytoplasm.
19. describe induction of the Drosophila hsp70 gene by heat shock: at 36.7-37
the heat-shock transcription factors (HSTF) cannot bind to heat-shock response elements
(HSEs) and there is NO transcription
at 41-42, the HSFT can bind to HSEs, and transcription occurs
20. T/F: the same transcription factor can play different roles in different cells: true 21.
describe coordinated gene regulation: -a single stimulus may turn on multiple genes
because these genes have common regulatory sequences in their promotors and/or
enhancer
-a single gene may be regulated by more that 1 response element; can respond to
multiple stimuli
22 describe how genes can be regulated based on RNA stability: the amount of mRNA
depends on rate of mRNA synthesis and rate of mRNA degradation
-different paths of degradation: deadenylation independent decapping, decapping,
deadynlation, and nonstop decay 23. describe deadenylation independent decapping:
nonsense mediated decay; m7Gpp cap
is removed but polyA tail is not
24. nonsense mediated decay: RNA degradation pathway that detects premature stop
codons and signals for subsequent degradation
-located 50nt upstream of splice site
-at stop codon, termination factor recruits UPFI to ribosome to degrade RNA
25. describe deadnylation: remove polyA tail with 3' --> 5' exonucleolytic decay
1. enhancers: regions of the DNA that interact with regulatory proteins to stimulate
transcription of nearby genes
-can be located upstream, downstream, or within a gene it regulates
2. basal transcription apparatus diagram:
3. silencers: control regions of DNA
-when TFs bind to a silencer, gene expression is repressed
-may be located thousands of bps away from gene they control
4. insulators: stretch of DNA (~42bps) that form a genetic boundary element that blocks
the interaction between enhancers/silencers and promoters
-function: to prevent a gene from being influenced by the activation or repression of its
neighbors
5. transcription factors: binds DNA and stimulate transcriptions
-many different kinds (ex. OCT, CAAT, GC, etc)
6. regulatory proteins: bind to specific DNA regions within the promoter
7. some single nucleotide substitutions can affect the levels of ______________:
transcription
8. dimerization domain: specialized for polypeptide interactions
-homodimers and heterodimers
9. homodimer: multimeric proteins made of identical subunits
10. heterodimer: multimeric proteins made of non-identical subunits
11. transcriptional _________ interact with each other to create novel
specificities-
,: regulators
-homo/heterodimers can regulate different strands because they have new specifications
12. repressor proteins: suppress transcription initiation by recruiting co-repressors
13. what are 2 functions of co-repressors: -repressors can recruit co-repressors
that prohibits RNA pol machinery to associate with the promoter
-repressors can recruit co-repressors that close chromatin
14. _________ can be active or passive: repressors
15 describe active v passive repressors: active- repressor bound to dimer to stop
transcription passive- half of dimer interacts with a protein that prevents it from binding
to DNA
16. what 4 ways can indirect repression operate:
1) competition due to overlapping binding sites
2) Quenching- repressor binds to activation domain
3) Cytoplasmic Sequestration- binding to activator and keeping it in cytoplasm
4) Heterodimerization- binding to activator and preventing homodimerization
17. describe the Wnt signaling pathway: seecreted glycoprotein that binds to a
ligand to regulate growth control and tissue patterning
-in the absence of Wnt, B-catenin is degraded; integration with Gro and TCF makes the
transcription factor act as a repressor
-in the presence of Wnt, B-cantenin is translocated to the nucleus; Gro is ubiquinated;
combo of B-cat and XIAP make
TCF act as an activator
18. how do steroid hormones regulate gene expression: the steroid hormone
will enter its target cell and will bind to a protein molecule
, the hormone receptor complex binds to a hormone response element
the transcript is processed and is transported to the cytoplasm.
19. describe induction of the Drosophila hsp70 gene by heat shock: at 36.7-37
the heat-shock transcription factors (HSTF) cannot bind to heat-shock response elements
(HSEs) and there is NO transcription
at 41-42, the HSFT can bind to HSEs, and transcription occurs
20. T/F: the same transcription factor can play different roles in different cells: true 21.
describe coordinated gene regulation: -a single stimulus may turn on multiple genes
because these genes have common regulatory sequences in their promotors and/or
enhancer
-a single gene may be regulated by more that 1 response element; can respond to
multiple stimuli
22 describe how genes can be regulated based on RNA stability: the amount of mRNA
depends on rate of mRNA synthesis and rate of mRNA degradation
-different paths of degradation: deadenylation independent decapping, decapping,
deadynlation, and nonstop decay 23. describe deadenylation independent decapping:
nonsense mediated decay; m7Gpp cap
is removed but polyA tail is not
24. nonsense mediated decay: RNA degradation pathway that detects premature stop
codons and signals for subsequent degradation
-located 50nt upstream of splice site
-at stop codon, termination factor recruits UPFI to ribosome to degrade RNA
25. describe deadnylation: remove polyA tail with 3' --> 5' exonucleolytic decay
