and techniques Genetic approaches Suppressor screen Enhancer screen Phenotypic screen Epistasis analyis Complementation tests Mosaic analysis Transformation rescue by TBd92btU

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									             General idea and concepts of cell-cell signaling
Cell signaling: Mechanisms that one cell uses to communicate and influence the
behavior of another cell. In a broader sense, the signaling could include environmental
cues received by a cell such as smell, light, mechanic pressure, and heat etc.


                          Three ways of cell signaling

 long-ranch signaling by secreted molecules
 contact signaling by plasma-membrane-bound molecules
 contact signaling via GAP junctions
Receptors:

a. Enzymed-linked receptors
-receptor protein kinases: tyrosine kinases, serine/thronine kinases
- receptors coupled to protein kinases
-protein tyrosine phosphatase receptors
-ANF receptor, ligand binding leads to activation of intrinsic guanylyl cyclase
catalytic domain
b. G protein-linked seven transmembrane receptors
c. Ion channel-linked receptors
d. Intracellular Receptors--Steriod hormone receptors
e. Receptors with death domain
Signal transduction pathways

- Wnt signaling pathway
- Notch signaling pathway
- RNAi pathway
- pathways for cell death
-genetic pathway
-biochemical pathway
-death signaling pathway
-engulfment signaling pathway
Embryo development

Mosaic Development (autonomous specification: determined by local determinants
and no cell-cell interaction)
Experimental test: remove one blastomere, the blastomere still develop as it will be
in the original embryo

Regulative Development (conditional specificaiton: determined by cell-cell
interaction and local determinants not important; e.g. mouse)
Experimental test: if remove one blastomere, the other blastomere will take over
and the embryo is fine.

Intermediate (Xenopus, fly and C. elegans)
Approaches and techniques

Genetic approaches

Suppressor screen
Enhancer screen
Phenotypic screen
Epistasis analyis
Complementation tests
Mosaic analysis
Transformation rescue
Sequencing of mutations
Biochemical approaches
Co-IP
Yeast 2-hybrid
hard-core purification
mass spectrometer analysis
Western blot analysis
Enzymatic assays (kinases, proteases)


Molecular Biological approaches
Over-expression
dsRNA injection


Cell Biological approaches
Cell or tissue isolation, mixing, and transplantation
Micro-manipulation
Immunostaining
GFP fusion labeling
LacZ staining
Advantage or disadvantage of various approaches
Genetics approach
Help systematically identify what are the important components in a particular
biological process and what are their related relationships in the pathway. But
genetics can not reveal the mechanisms underlying the biological process.

Biochemical approaches
Very effective in elucidating the detailed mechanisms underlying a biological
process. Can also help identify components of a biological process but usually
can not give out the whole picture and is restricted by the availability and relative
quantity of materials, the experimental techniques or methods.
      Good luck!

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