BCH5413 EXAM II UPDATED ACTUAL
Exam Questions and CORRECT Answers
Name some of the complexities of eukaryotic transcription when compared to prokaryotic
transcription - CORRECT ANSWER - * Eukaryotic transcription involves decondensing
chromatin
* The three main polymerases in eukaryotic systems are not sequence specific. They require
transcription factors to recognize promoter sequence for them. In prokaryotes, te sigma factors
are sequence specific to -10 region in the promoter
* In eukaryotes, transcription and translation are compartmentalized and divided by the nucleus,
transcripts need to be transported to cytoplasm upon creation
* Eukaryotic organisms form pre-mRNA and then further process it to make mature mRNA
What are the first three steps of pre-initiation complex formation (PIC formation)? - CORRECT
ANSWER - 1) TBP (a subunit of TFIID) recognizes and binds the TATA box
2) TFIIB binds and complexes with TFIID at the promoter
3)Recruitment of RNA pol via association with TFIIF
What are the last three steps of PIC formation? - CORRECT ANSWER - 4) TFIIE Joins
and associated with the formed PIC
5) TFIIE Recruits RFIIH to from transcription initiation complex
6) TFIIH has kinase activity and phosphorylates the CTD of RNA pol II which promotes the
transition from transcription initiation to elongation
What is the function of TFIID - CORRECT ANSWER - TBP+13 TAFS recognize and
bind TATA Box and other core promoter elements, Helos to confiugre DNA to RNA POL II
surface
General transcription factor
contains the TATA box binding proteins, TBP association factors (TAFs)
it nucleates PIC assembly though TBP binding to TATA sequence or TAF binding to other
promoter sequences
, What is the function of TFIIB - CORRECT ANSWER - It contributes to promoter
selection, recruitment of TFIIF association with RNA pol II
How did the linker scanning experiment demonstrate that the TATA box is required for
transcription while the GC boxes are not? - CORRECT ANSWER - * mutated regions
throughout the TK promoter
- Regions mutated within the TATA box destroyed promoter activity
- regions mutated in GC box regions affected transcription efficiency but did not abolish it.
Name the two models for PIC assembly. What is the one similarity between the two? -
CORRECT ANSWER - 1) Sequential assembly pathway
2) RNA polymerase holoenzyme pathway
Promoter recognition occurs by TFIID in both
What is the function of the mediator? - CORRECT ANSWER - Just like it sounds
1) transmits signals from transcription factors to polymerase
2) functions as a coactivator
3) is shown to interact with the CTD of RNA Pol II
4) required for transcription activation
In general overview, what are the steps necessary for transition from the PIC to the EEC? -
CORRECT ANSWER - 0) initiation- formation of the PIC- initially transcribing complex
(itc)- includes abortive initiation
1) promoter clearance/ escape- early elongation complex (EEC)- promoter escape complete,
nascent RNA stabiliy associates with transcription complex
2) promoter proximal pausing- initially characterized in MYC gene but now found genome wide
3) Productive elongation transcription elongation through nucleosomes
Exam Questions and CORRECT Answers
Name some of the complexities of eukaryotic transcription when compared to prokaryotic
transcription - CORRECT ANSWER - * Eukaryotic transcription involves decondensing
chromatin
* The three main polymerases in eukaryotic systems are not sequence specific. They require
transcription factors to recognize promoter sequence for them. In prokaryotes, te sigma factors
are sequence specific to -10 region in the promoter
* In eukaryotes, transcription and translation are compartmentalized and divided by the nucleus,
transcripts need to be transported to cytoplasm upon creation
* Eukaryotic organisms form pre-mRNA and then further process it to make mature mRNA
What are the first three steps of pre-initiation complex formation (PIC formation)? - CORRECT
ANSWER - 1) TBP (a subunit of TFIID) recognizes and binds the TATA box
2) TFIIB binds and complexes with TFIID at the promoter
3)Recruitment of RNA pol via association with TFIIF
What are the last three steps of PIC formation? - CORRECT ANSWER - 4) TFIIE Joins
and associated with the formed PIC
5) TFIIE Recruits RFIIH to from transcription initiation complex
6) TFIIH has kinase activity and phosphorylates the CTD of RNA pol II which promotes the
transition from transcription initiation to elongation
What is the function of TFIID - CORRECT ANSWER - TBP+13 TAFS recognize and
bind TATA Box and other core promoter elements, Helos to confiugre DNA to RNA POL II
surface
General transcription factor
contains the TATA box binding proteins, TBP association factors (TAFs)
it nucleates PIC assembly though TBP binding to TATA sequence or TAF binding to other
promoter sequences
, What is the function of TFIIB - CORRECT ANSWER - It contributes to promoter
selection, recruitment of TFIIF association with RNA pol II
How did the linker scanning experiment demonstrate that the TATA box is required for
transcription while the GC boxes are not? - CORRECT ANSWER - * mutated regions
throughout the TK promoter
- Regions mutated within the TATA box destroyed promoter activity
- regions mutated in GC box regions affected transcription efficiency but did not abolish it.
Name the two models for PIC assembly. What is the one similarity between the two? -
CORRECT ANSWER - 1) Sequential assembly pathway
2) RNA polymerase holoenzyme pathway
Promoter recognition occurs by TFIID in both
What is the function of the mediator? - CORRECT ANSWER - Just like it sounds
1) transmits signals from transcription factors to polymerase
2) functions as a coactivator
3) is shown to interact with the CTD of RNA Pol II
4) required for transcription activation
In general overview, what are the steps necessary for transition from the PIC to the EEC? -
CORRECT ANSWER - 0) initiation- formation of the PIC- initially transcribing complex
(itc)- includes abortive initiation
1) promoter clearance/ escape- early elongation complex (EEC)- promoter escape complete,
nascent RNA stabiliy associates with transcription complex
2) promoter proximal pausing- initially characterized in MYC gene but now found genome wide
3) Productive elongation transcription elongation through nucleosomes
