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Post on 02-Feb-2016
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Question:
How do we know where a particular protein is located in the cell?
Principle of Fluorescence
Cell with fluorescent molecule
Experimental Approaches for Protein Localization
1. Small Molecule Dyes (e.g. DAPI)
2. Immunostaining (dye-conjugated antibodies)
3. Green Fluorescent Protein (GFP) “Tagging”
Aequorea victoria
Green Fluorescent Protein (GFP)
ExcitationWavelength(e.g. 490 nm)
EmissionWavelength(e.g. 510 nm)
GFP
Gene Expression
DNA (Gene X)
mRNA
Protein X
Transcription
Translation
GFP Tagging Approach
mRNA
DNA (Gene X -GFP “Fusion”)
Protein X-GFP “Fusion”
Transcription
Translation
GFP Tagging Experiments
Nuclei Mitotic Spindle
Histone-GFP Tubulin-GFP
Question:
Where is the Cdc10 protein located in a yeast cell?
*
Septin Protein Family
GFP Tagging Approach
mRNA
DNA (CDC10 -GFP “Fusion”)
Cdc10-GFP “Fusion”
Transcription
Translation
Project OverviewIsolation of CDC10 gene Open Reading Frame
Purification of Genomic DNA from yeastPolymerase Chain Reaction (PCR)
Construction of CDC10-GFP “fusion” gene
Restriction endonuclease/LigaseCloning DNA in E. coli
Introduction of CDC10-GFP “fusion” gene
into yeast cells
Observe Cdc10 protein localization in living cells with fluorescence microscopy
GFP Tagging of Cdc10
mRNA
DNA (CDC10 -GFP “Fusion”)
Cdc10-GFP “Fusion”
Transcription
Translation
Saccharomyces cerevisiae (Yeast)
Eukaryotic cell15 million bp DNA~ 6000 genesComplete genome sequence known!
Copies of CDC10 Gene Open Reading FramePg. 350
Purify genomic DNA
~ 6000 genes
Lab #1 & 2
15 million bp
PCR
Taq DNAPolymerase
Pg. 202 DNA Synthesis
Primer
CDC10-Forward
5’ – GTGGTGAAGCTTATGTCCATCGAAGAACCTAG – 3’
CDC10-Reverse
5’ – GTGGTGAAGCTTTCTAGCAGCAGCAGTACCTGT – 3’
CDC10 Gene Primers
CDC10 GeneSequence
(non-template strand sequence)
First Cycle of PCR
Pg. 349
(94o C.) (52o C.)(72o C.)
CDC10
For
Rev
5’5’ 3’3’
3’
3’ 5’
5’
Three Cycles of PCR
Pg. 349
Agarose
Gelidium comeum (kelp)
Ethidium Bromide
+
+
Restriction Endonuclease Reaction
HindIII (37o C.)
5’
5’
3’
3’
5’
5’3’
3’3’
3’5’
5’
Ligation Reaction
“Compatible” ends
DNA Ligase + ATP (15o C.)
HindIII recognition site is reconstituted
5’
5’3’
3’3’
3’5’
5’
3’
3’
5’
5’
1. Annealing
2. Phosphodiesterbond formation
Pg. 344
Construction of a Recombinant DNA Plasmid
(insert)
CDC10-For
5’ – GTGGTGAAGCTTATGTCCATCGAAGAACCTAG – 3’
CDC10-Rev
5’ – GTGGTGAAGCTTTCTAGCAGCAGCAGTACCTGT – 3’
CDC10 Gene Primers
GTGGTGAAGCTTATGTCCATCGAAGAACACCACTTCGAATACAGGTAGCTTCTT
ACTGCTGCTGCTAGAAAGCTTCACCACTGACGACGACGATCTTTCGAAGTGGTG
5’3’ 5’
3’
AGCTTATGTCCATCGAAGAA ATACAGGTAGCTTCTT
ACTGCTGCTGCTAGAATGACGACGACGATCTTTCGA
5’3’ 5’
3’
CDC10 ORF DNA from PCR
HindIII
Ori
AmpR
pGFP Plasmid
HindIII
Ori
AmpR
pGFP Plasmid
HindIII
AGCTTATGTCCATCGAAGAA ATACAGGTAGCTTCTT
ACTGCTGCTGCTAGAATGACGACGACGATCTTTCGA
5’3’ 5’
3’
CDC10 orf
ACT GCT GCT GCT AGA AAG CTT ATG TCT AAA GGTHindIII Site
- Thr - Ala - Ala - Ala - Arg - Lys - Leu - Met - Ser - Lys - Gly -
Cdc10 GFP
5’ 3’
pCDC10-GFP Plasmid
CDC10 orf GFP orfACT1pHindIII HindIII
Transformation of E. Coli
plasmid
Pg. 344
(Ampicillin sensitive)
(AmpR)
(LB growth medium with ampicillin)
DNA Cloning
pCDC10-GFP
PlasmidPurification (Lab #6)
Bacterial Transformation(Lab #5)
Ori
AmpR
pGFP Plasmid
HindIII
Ampicillin
Inhibits cell wall synthesis
Pg. 344
(Ampicillin sensitive)
(AmpR)
DNA Cloning
pCDC10-GFP
(LB-amp Plate)
(LB-amp)
Transformation of E. Coli
plasmid
Log Phase GrowthCold (4oC)CaCl2
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