1. Central Dogma
How all cells express genetic information

2. Gene Expression
Machinery in cell determines DNA segments to transcribe
Different genes transcribed at different rates

3. RNA Structure Sugar-phosphate backbone Bases Projecting from backbone
Polarity- 5’ and 3’ ends

4. Sugar Component Of RNA
Ribose (RNA) instead of deoxyribose (DNA)

5. Base Component Of RNA
Uracil (RNA) instead of thymine (DNA)

6. Folding Of RNA
Single-stranded
Intramolecular base-pairing

7. Transcription RNA synthesis from DNA template
Chemistry similar to DNA replication

8. RNA Polymerase Local unwinding of DNA Stepwise synthesis of RNA 5’→3’
No primer needed
RNA release and DNA rewinding

9. Initiation & Termination In Bacteria
s factor recognizes promoter
Unwind DNA & begin RNA
synthesis
s factor dissociates &
processive elongation
Terminated by destabilizing
structure in RNA

10. Determining Template Strand
Dependent upon orientation of promoter
Varies from gene to gene

11. Eucaryotic RNA Polymerases
RNA polymerase I rRNA genes
(5.8S, 18S, and 28S)
RNA polymerase II all protein-coding genes
(produce all mRNA)
RNA polymerase III tRNA genes, 5S rRNA genes

12. Transcription Initiation By RNA Polymerase II
Requires general transcription factors
TFIID/TBP binds to TATA box
TFIIH helicase exposes DNA & transcription begins
TFIIH kinase causes release of general factors & processive elongation

13. Transcriptional Activators and Chromatin Modifiers
Activators: DNA binding proteins; promote assembly of RNA polymerase II and general transcription factors
Chromatin modifiers allow greater access to DNA

14. mRNA Processing Eucaryotes Synthesis of primary transcript
5’ and 3’ modifications
Removal of introns

15. Capping Of 5’ End Addition of 7-methylguanosine Reverse linkage of GMP
Addition of methyl group

16. Intron/Exon Arrangement
coding sequences (exons) separated by intervening sequences (introns)

17. Splicing Reaction two sequential transesterifications
Adenine (branch point) in the intron reacts with 5’ splice site
Free 3’ end of exon reacts with the 5’ end of next exon

18. Sequences That Determine Splicing
Three short segments in each intron at beginning, end, and branch point

19. Spliceosome Set of snRNPs each composed of snRNA and proteins
snRNA recognition of splice sites and catalysis

20. Alternative Splicing
Multiple proteins encoded by one gene

21. Mutations To Splice Sites
Exon skipping or activation of a cryptic splice site

22. Processing Of 3’ End Cleavage at specific sequence
Addition of polyA tail

23. CstF, CPSF bind recognition sequence on RNA
Poly-A polymerase

24. mRNA Export Nuclear pores serve as gates
Proteins binding to processed mRNA mark as export ready

25. Synthesis Of rRNA Multiple copies of genes
Precursor rRNA that is modified and cleaved

26. Nucleolus Ribosome factory rRNA gene clusters
Transcription, processing, assembly