Chapter 10: Eukaryotic RNA Polymerases & Promoters Flashcards
active site
-stabalizes growing nucleotide
lcoated at base of the cleft
binds Mg2+ ions (function?)
Pore 1 (x3)
facilitates immature RNA extrusion and binds transcriptional elongation factor TFIIS
-may also funcition as site for nucleotides to enter and for RNAs to be extruded during backtracking
Rpb2
homologous to?
contains catalytic site, is essential for elongation
homologous to B subunit
Polymerase form 2
clamp is open, allowing linear DNA to enter complex, contact Rpb1/2, and initiate transcription
contains catalytic site, is essential for elongation
homologous to B subunit
Rpb2
homologous to?
- crystallized yeast RNA Pol II structure
- determined RNA pol2 structure during elongation in which clamp is closed over both DNA template and RNA product
Roger Kornberg et al. (x2)
clamp is open, allowing linear DNA to enter complex, contact Rpb1/2, and initiate transcription
Polymerase form 2
- rudder
- lid
- zipper
3 loop regions that extend from the clamp
- initiates/facilitates dissociation of DNA-RNA hybrid
- guides RNA exit + maintains dissociation of DNA template
- helps stabilize transcription bubble + initiates dissociation of DNA template
located in nucleolus
synthesizes ribosomal RNA (rRNA)
RNA polymerase 1
Rpb4/9
non-essential but may help avoid nonspecific binding
binds DNA directly, contains CDT
homologous to B’/a subunits of E. coli polymerase
Rpb1
homologous to?
required for transcription (may be targets of transcriptional activators)
Rbp3/6/12/5/10
located in nucleoplasm
synthesizes transfer RNA (tRNA) precursors and the 5srRNA
RNA polymerase 3
locoated at base of the cleft
binds Mg2+ ions (function?)
active site
-stabalizes growing nucleotide
Class 3 promoters (x2)
- 3 types distinguished by…?
- utilize elements outside promoter such as…?
have internal promoters + transcribe mostly snRNAs and tRNAs
- distinguished by RNA types transcribed and promoter boxes
- such as enhances/activators & silencers
Eukaryotic features (x3)
- membrane-bound organelles
- distinct nucleus & nucleolus
- divide by mitosis
used alpha-amanitin to determine transcriptional activity and function of each polymerase
inhibitory concentrations:
- Polymerase III=20ug/ml
- Polymerase II=.02ug/ml
roeder et al
non-essential but may help avoid nonspecific binding
Rpb4/9
lack TATA box, usually contain AT-rich sequence, contain 2 major regions
- located between positions -45 and +20; function=essential for transcription
- located between positions -156 and -107; function=enhances transcription
Class 1 promoters (x3)
- core promoter region location & function?
- upstream promoter element (UPE) location & function?