1. Transcription

2. Transcriptiontion- the synthesis of RNA using DNA as a template. Four stages: Initiation, Elongation, Termination, Post-transcriptional modification Transcription

3. Upstream 5’ end vs Downstream 3’ end Terminology of Transcription

4. Initiation

5. Consensus sequence Transcription Start Site is Promoter

6. DNA dependent RNA polymerase zinc metalloenzyme  ßß’ core enzyme with  subunit, holoenzyme ± other subunits the  subunit causes specific binding to promoter also dependent on NTP’s (and Mg 2+ as usual) no requirement for primer RNA Polymerase

7. Elongation

8. Termination Least well understood Rho (  -dependent vs  -independent

9. Comparison with Eukaryotes Prokaryotes Eukaryotes promoter promoter + enhancers Polymerase Polymerases I, II and III Rho not Rho not processing Processing

10. Post-transcriptional Processing of mRNA ( nucleus) Cap –functions: transport, recognition, prevents exonucleases poly A tail –functions: prevents exonucleases, recognition, other? –Less in prokaryotes Introns spliced out- eukaryotes only

11. Post-transcriptional Processing of mRNA - Capping

12. Post-transcriptional Processing of mRNA - Methylating the Cap

13. Post-transcriptional Processing of mRNA - Polyadenylation

14. Post-transcriptional Processing of mRNA - Splicing out Introns Complicated “snurps” - small nuclear ribonucleoproteins snurps 1-6 bind at specific times (no details) RNA catalysts lariat structure

15. Processing of rRNA RNA synthesized longer than needed portions methylated non-methylated parts degraded RNA associates with protein final shape globular

16. Processing of tRNA Synthesized longer than needed bases modified Know the cloverleaf structure