1. Lecture 13
Post-transcriptional processing of mRNA
Membranes again

2. Post-transcriptional Gene control (Chapter 8)

6. hnRNP proteins coat the RNA immediately upon its exiting from RNA polymerase
Human hnRNP A1 (red) and C (green) proteins distribute differently in the cytoplasm of a heterokaryon

8. Consensus sequence around splice sites

9. The chemistry of RNA splicing

10. The mutated mismatched A is in this position

12. Exonic splicer enhancers
Average length of intron ~3500 bases
exons are ~ 150 bases long
SR proteins (serine-arginine rich) interact with exonic splicing enhancers,
mediate cooperative binding U1 snRNP to a true 5’ splice site.
This helps forming cross-exon recognition complex

13. Membranes and lipids Wikipedia
Functions: compartmentation, maintain internal milieu, transport, energy transduction, signal propagation, cell-cell communication, ingestion, secretion, sensation, storage etc.

14. Membranes are self-organizing structures
Staining artifact
due to binding of a contrasting agent (Uranyl or Osmium) to the polar headgroups
Membranes are self-organizing structures

16. PE, PC: zwitterions, PS:anionic PS and PE have H-bonding capacity
(Phospholipids)
glycerol
PE, PC: zwitterions, PS:anionic
PS and PE have H-bonding capacity

17. Phosphatidic acid (PA)
Phosphatidyl glycerol (PG)

18. Phosphatidylinositol
Phosphatidylinositol diphosphate (PIP2)

19. Critical trans double bond
sphingosine
ceramide NH

20. Cholesterol

21. Lipids have their spontaneous curvature

22. Micelles, Liposomes and Lamellar phases
SDS

23. Lipid Bilayers are dynamic
distributions of phosphate and carbonyl groups and lateral pressure profiles
From S. Feller

24. Distribution of groups along the z-axis
from S. White