1. Angiostatin
    Fragment of plasminogen cleaved in tumours, prevents the development of micro-metastases
  2. Endostatin
    On chr 21, so overproduced in Down's: prevents development of micro-metastases
  3. Example of aneuploidy (not down's)
    Loss of chr 10: glioblastomas
  4. K-Ras missense mutations cause
    pancreatic tumours
  5. Example of gene amplification problem
    Over expression of myc causes advanced neuroblastomas
  6. Example of translocation causing disease
    Chronic myeloid leukaemia: Abl Chr 9 -> Abl binds to BCR gene on Chr 22: fusion gene called Bcr-ABL. Bcr-abl tyrosine kinase signalling blocked by glivec!
  7. Bacterial retrotransposon
    Tn3: carries antibiotic resistance
  8. Problems with mismatch repair cause
    hereditary non-polyposis colorectal cancer syndrome
  9. Proteins to recognise mismatches
    • Mut S and Mut L in bacteria
    • Eukaryotes: MSH (Mut S Homologue) identifies site, MLH (Mut L Homologue) (and MHL) cleave
  10. Problems with NHEJ
    Mutations in DNA ligase IV: some leukaemias
  11. HR things
    RecA, RAD51, RuvAB (used in restarting broken replication forks)
  12. Methylation of DNA
    • Bacteria: A in GATC by Dam methyltransferase
    • Eukaryotes: CpG islands - genomic imprinting (Prader-Willi 15q)
  13. Prader-Willi /Angelman
    • 15q
    • (low muscle tone, short, incomplete sexual development, hyperphagia)
    • (happy puppet)
  14. Rho factor needs
    50-90nt region with high C content
  15. 3 drugs to stop RNA transcription
    Actinomycin D (intercalates), Rifamycin (binds B subunit), a-amanatin (interferes with translocation)
  16. DNA footprinting
    Label with 32P. Add binding protein. Limited nuclease digestion with DNAse 1. Visualise using autoradiography.
  17. How do we know most promoters are nucleosome free?
    DNAse1 digestion occurs fastest in actively transcribed DNA
  18. 3 ways to alter histones
    • Methylation: 3 to lysine - more bulky: REPRESSES TRANSCRIPTION
    • Acetylation to lysine: less positive charge
    • Phosphorylation of serine: 2 negative charges
  19. 5'cap, 3 tail
    • m7g5'ppp5'n
    • polyadenate polymerase
  20. how is eukaryotic transcription stopped
    Pol II carries on for ages. pre-mRNA is cleaved between AAUAAA and GU/U rich sequence.
  21. WT1
    • TF. Recognises GC/TC rich regions.
    • 2 domains: N: Pro + Glu rich activation domain
    • C: DNA binding, 4 Zn fingers
    • Normal cells: 4 alternatively spliced variants. truncated forms lack domains.
  22. RNA editing
    hydrolytic deaminations (C->U or A->I)
  23. Wobble example
    Inosin can bind to U, C or A
  24. When does large subunit bind?
    Initiating AUG codon
  25. Distinguishing between AUG codons
    • Eukaryote: first one along from 5'cap
    • Bactera: Shine Dalgarno sequence (GGAGG) recognised by AACAA in 16S rRNA of 30S subunit
  26. Non-cap dependent translation initiation
    Internal initiation of translation using IRES (internal ribosomal entry site). Found using dicistronic assays: assayable enzymes. In picornaviruses (polio, hep c). Long 5' UTR. Hep C IRES major drug target.
  27. Translation
    • Met-tRNA to P site, via eIF2 (eukaryotic initiation factor) (interferon response, kinase)
    • All AA-tRNA to A site, via GTP and EFTu (EEF1)
    • EEFtu-GDP dissociate
    • Peptide bond by transfer of peptide from P to A site, via peptidyl transferase activity of large ribosomal subunit (ribozyme) - no energy use.
    • Translocation, via GTP and EFG (EEF2)
  28. Riboswitches
    DNA sequences, bind small molecules. eg thiamine.
  29. Lysosyme sequence
    KFERQ: lots from liver, kidney during fasting.
  30. Ubiquitination
    E1, E2 (to SH) (activating, conjugating). UBIQUITIN LIGASE: to lysine, isopeptide bond. D box in cyclins required?
Card Set