Transcription and RNA Processing Flashcards
Functions of TFIIE? (2)
- recruits TFIIH
- ATPase and helicase activity
When does the PIC disassemble?
As RNA Pol II begins transc
3 major functions of TFIIH?
- helicase activity @ promoter
- phosphorylates Pol II @ CTD
- recruits NER proteins for repair
Molecule involved in Death Cap mushroom poisoning?
Alpha-amanitin
Mechanism of of alpha-amanitin? (3)
- cyclic octapeptide poisonous to RNA Pol II
- binds back side of RNA Pol II and restricts its flexibility
- significant reduction of RNA Pol II transcripts and protein
Symptoms of alpha-amanitin poisoning? (5)
- mimics flu
- liver damage
- kidney failure
- coma
- death
Role of Tat protein in HIV-infected cells?
- encoded by virus
- acts as an anti-termination factor
Mechanism of HIV Tat protein? (4)
- Tat binds host’s cyclin T proteins
- Cyclin T activates host CDK9
- CDK 9 phosphorylates CTD of RNA Pol II
- prevents premature termination of HIV transcript
How is Tat protein used in ARV AIDS therapy?
Can inhibit Tat activity to inhibit HIV transc
Causes of beta-thalassemia? (2)
- mutation(s) in the beta-globin locus
- mutation in splicing junctions
Effects of beta-thalassemia? (2)
- impaired RBC function
- proteolysis of subunit
Mechanism of beta-thalassemia? (2)
- mutations interfere w/ normal RNA synth/processing
- less beta-globin and more gamma-globin transcribed
Modifications to 5’-phosphate end of RNA molec? (3)
- 7-Methyl-guanosine cap added to 5’-triphosphate end of hnRNA thru 5’,5’-triphos linkage
- 2’-methylation of 1st ribose sugar
- 2’-methylation of 2nd ribose sugar
Name of primary methyl donor?
S-AdenosylMethionine (SAM)
What RNA mod facilitates nuclear export of mRNA?
poly(A) tail
Bases in splice donor and acceptor sites?
- donor = GU
- acceptor = AG
Components of spliceosome? (2 categories)
- snRNA U1, U2, U4, U5, and U6
- snRNPs
Mechanism of Systemic lupus erythematous (SLE)?
- autoimmune disorder that attacks snRNPs, among other things
What disease:
- absence of beta-globin expression
Beta-thalassemia Major or Cooley’s anemia
What disease:
- reduced expression of beta-globin
Beta(+)-thalassemia or Beta-thalassemia Minor
What gene is defective in Dystrophia Myotonica (DM)?
Dystrophia Myotonica Protein Kinase (DMPK) gene
Main cause of DM?
mRNA transcript w/ increased trinucleotide repeats 5’-CUG-3’
Mechanism of DM? (5)
- inability to export DMPK mRNA from nucleus due to high no. of tri-nt repeats
- muscleblind protein binds CUG repeats inside nucleus
- inhibits CUG binding protein
- increase in CUG-BP expression in nucleus
- mediates aberrant splicing events in adult tissues
3 major symptoms of DM? Associated proteins?
- impaired myocardial contraction – cardiac Troponin T protein (cTNT)
- insulin resistance – insulin receptor protein (IR)
- repeated firing of AP (myotonia) –> muscle wasting – muscle-spec Cl- ion channel protein (CIC-1)
