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29 Cards in this Set
- Front
- Back
describe the components of a transcription unit
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promoter, through terminator
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genes transcribed left to right use which strand as template
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use the bottom strand as template
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genes transcribed right to left use which strand as template
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use top strand
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-35, -10
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-35: where RNA pol initially interacts
-10 pribnow |
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how many RNA pols do prok have?
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one
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describe RNA pol in transcription
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holoenzy with six subunits
sigma - binds promoter, stabalizes/enhances affinity for binding beta - active site/catalytic binds nucleoside triphosphates beta' - binds DNA template omega - renatures polymerase after its been dissociated alpha - assembly and regulation syn first 9nt's then initiation ends and sigma released |
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Rho indep termination of transcription, whats in the stem?
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GC
RNA pol is released |
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RHO dependent
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atpase six subunits
binds C rich recog site in RNA chain 5'3' helicase catches up with RNA pol when it pauses REQ ATP |
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PROK rRNA
precursor? 30S? 50S? |
30S precursor
16S 23S 5S 30S - 16S 50S - 23S 5S |
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Euk rRNA
precursor 40S 60S |
TRanscribed and nontranscribed spacers
40 - 18S, 60 - 5.8 28 5TRNA(pol III) |
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RNA pol II
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more than 10 subunits
two largest are catalytic activity C-terminal domain (phos'd by TFIIH to proceed from initiation to elongation) binds dna non spec |
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RNA pol I in euk
General transcription factors |
UBF1 - binds core promoters
SL1 -binds ubf1 RNApol I is then recruited |
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initiator is purine or pyrimidine rich?
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pyrimidine
conserved sequence around start of transcription |
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What else is in the promoter besides the core promoter
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URE - upstream regulatory elements, bind specific transcriptional activators
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TRanscriptional activators have what two domains
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DNA binding - zn finger hlh homeo domains, leu zipper
transcription activation - glu rich, facilitates interaction with other factors |
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activation domain of transcriptional activator does what
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initiation and elongation rate
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What is important about TAF's?
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one of them has a HAT activity
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what are HDACs
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histone deacetylases remove actyl groups from histon tails
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EUK pre-initiation complex
PIC |
TBP binds minor groove - only member to make direct contact
TFIID = TBP + TAF's TFIIA/B join stabilizing its binding TFIIF (atp dep helicase)brings in RNA pol II TFIIE joins |
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Initiation of transcription in euk
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first phosphodiester bond forms using ATP hydrolysis
TFIIH (helicase) and TFIIJ join TFIIH phosphorylates C terminal domain of RNA pol II |
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how do you move from preinitiation complex to initiation?
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TFIIH phosphorylates C terminal domain of RNA pol II
release GTF's, after 60-80 nt's rest of TFII's are released |
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Wilms disease
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WT-1 is a tumor suppressor
repressor activity of WT-1 inactivated when it's mutated in WILMS TUMOR |
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Post transcriptional (have made the mRNA) processing in euk tRNA
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tRNA addition of CCA, 3' end trimmed, 5' end trimmed, intron in anticodon stem removed, base modifications
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POST Transcriptional(have made the mRNA) processing in EUK
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tRNA, mRNA cap/tail(ATP, not req for getting out of nucleus), splicing,
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Four groups of introns and how you remove them
I II* III* IV |
I and II - ribozyme autocat, lower euk
II and III- lariat, autocat(self splicing) III spliceosome IV endonuclease and ligase (yeast) |
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Spliceosome
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snRNA's and snRNP's (U1-6 lots of uracil)
REQ ATPfor assembly |
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name the three splice sites
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donor GU 5'
acceptor AG 3' A branch site |
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How does the spliceosome work
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U1 binds donor
U2 binds branch U4-6 bind and spliceosome is complete Activated A cleaves exon-intron 2'5'linkage acceptor cleaved |
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beta thalassemia
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improper splicing
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