1. Chapter 12 Processing pre-mRNA and Nuclear Transport
By:
Rachael Hattrup

2. Processing of eukaryotic Pre-mRNA
1) 5’ capping with 7-methylguanosine
3’cleavage at Poly (A) site
Polyadenylation added
250 in mammals
150 insects
100 yeasts
4) RNA splicing
Introns removed and exons kept.

3. 5’ Capping

4. Overview of mRNA processing in Eukaryotes

5. Macromolecular Transport into Nucleus
Nuclear envelope
Nuclear Pores
Nuclear pore complex (NPC)
Nucleoporins

6. Nuclear Pore Complex

7. Macromolecular Transport into Nucleus
2 Importins bind to create nuclear-import receptor
-Importin binds to Nuclear-localization signal (NLS) of “cargo” protein
2) -importin interacts with FG nuclear proteins to diffuse through NPC

8. Macromolecular Transport into Nucleus cont…
Ran-GTP interacts with importins causing conformational change creating less affinity for NLS
Ran-GTP transports importin out to cytoplasm

9. Transport into Nucleus

10. Macromolecular Transport out of Nucleus
1) Protein exportin 1 binds to Nuclear-export signal (NES) bound to “cargo” protein and Ran-GTP
2) Difusses through NPC
Ran-GTP converted to Ran-GDP releasing the complex

11. Transport out of Nucleus

12. The End
Questions?????