Title: Last Class: Gene Regulation 1. DNA-protein interaction, different motifs, techniques to study DNA-protein interaction 2. Gene regulation on DNAs, gene activators (acting on promoter, enhancer, chromatin etc), repressors 3. regulation of gene
1Last Class Gene Regulation1. DNA-protein
interaction, different motifs, techniques to
study DNA-protein interaction2. Gene regulation
on DNAs, gene activators (acting on promoter,
enhancer, chromatin etc), repressors3.
regulation of gene activators/repressors4.
integrated response.
2Posttranscriptional Regulations
3Posttranscriptional regulation possibilities
4Alternative RNA Splicing
5Alternative Splicing of RNA of the Drosophila
DSCAM gene (axon guidance receptors directing
growth cone localization)
6Negative and Positive Controls of Alternative
Splicing (active regulation)sometimes, the
splicing sequence is ambiguous, so constitutive
random splicing
7Antibodies (membrane-bound, secreted) in B
lymphocytecleavage regulated RNA processing
(CstF)
8RNA Editing (inserting Uracil at different sites
and change encoding sequence)
9Nuclear ExportRev binds to rev response elelent
(RRE), which binds to nuclear export receptor
(exportin 1) to regulate nuclear export even
without splicinga delay of virus infection
symptom
10Localization in cytoplasmalso determine the fate
of RNAs3 UTR (untranslated region)
113 UTR in regulating LocalizationRed intact 3
UTR,Green 3 UTR deleted
12Translational Regulation
13Negative Translational Controlaconitase inhibits
ferritin production
14Phosphorylation RegulationeIF-2B serving as GEF
for eIF-2 and promote translation
initiationphosphorylation locked eIF-2 in
inactive form
15Internal Ribosome Entry Site (IRES)
16Two Mechanisms of mRNA decay1. regular 3 tail
shortening followed by 5 decapping and
degradation2. endonucleolytic cleavage and fast
decapping and degrading
17The competition between mRNA translation and
decayinitiation machinery and deadenylation
proteins are all associated with 5 and 3
18With Iron, aconitase release enhances the
production of ferritin to bind iron while
destabilizes transferrin receptor mRNA to reduce
the transportation of more iron intracellularly
19Stop Codon CheckingShould after all the exons
(nonsense-mediated mRNA decaying)
20SiRNA MechanismRNase, ATP hydrolysis and RNA
helicase
21Summary
- Premature termination
- Alternative RNA Splicing
- 3 cleavage and Poly A addition
- RNA editing
- Necleus transportation
- Localization of RNA at the cytoplasm
- Translational initiation
- Degradation
22- Lipid Bilayers
- Cell Membrane
23Cell Membrane Views
24Phospholipid Molecule
25Hydrophilic and Hydrophobic Molecules interacting
differently with water
26Wedge-shaped lipids form micelles Cylinder-shaped
lipids form bilayers
27Spontaneous sealing of phospholipid bilayer
28Liposomes Proved the self sealing process
29Phospholipid mobility Lateral diffusion
Diffusion coefficient 10-8 cm2/sec Migrate in
seconds to cover the whole surface Flip-Flop
phospholipid translocators
30Cis-double bonds affect packing Saturated
packed and thick Unsaturated loose and
think Phase transition liquid to fluid
31Cholesterol and Glycolipids
32- Function of Cholesterol
- Provide structural support, prevent small
molecule to pass - Prevent tight packing and transition
33(No Transcript)
34Phospholipid types
35Microdomains on plasma membrane Lipid rafts (
50nm) Choresterol Sphingolipids (long saturated
chains) Other proteins
36Asymmetrical distribution of phospholipids and
glycolipids Protein kinase C (PKC) binds to
negatively charged phosphotidylserine to be
functional
37Phospholipids in cell signaling
PKC
Calcium
GEF, AKT, migrating front
38Phospholipase Cleavage sites
39Phosphotidylserine exposed on outer surface as
apoptosis signal
- Phospholipid translocator
- Scramblase
40Glycolipids Gm1 Ganglioside with charge can
serve as signal for lipid rafts, binds to Cholera
toxin
41Summary
- Lipid molecules phospholipids, cholesterol,
glycolipid, all amphipathic - Lipid bilayer, hydrophobic inside and hydrophilic
outside - Subdomains on membrane, asymmetry important for
functions - Phospholipids as signals
42Membrane Proteins
Integral membrane protein Peripheral membrane
protein
Glycosylphosphatidylinositol (GPI) anchor protein
43Fatty acid chain (acyl, N-terminal) or prenyl
group modifications (C-terminal)
Or geranylgeranyl
Or palmitic acid
44Hydropathy Plots Index of hydrophobicity
45Membrane proteins are glycosylated Sugar are
added in the lumen of the ER and Golgi apparatus,
therefore, sugar are outside of cell
surface Cytosol has reduced environment,
preventing disulfide bonds