Team:Freiburg Cloning Strategy
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The whole receptor construct consists out of a signalpeptide, an extracellular receptor domain, a GGGS-linker followed by transmembrane region and an intracellular split-reporter-protein. The signalpeptide-sequence according to the EGF-receptor erbb1 ensures the transport of the protein construct to the cytoplasmamembrane. A GGGS-linker is necessary to create a distance between membrane and the recognition-site to overcome cell surface structures as glycoproteins and glyclipids. The sequence of the transmembrane region is taken from the EGF-receptor erbb1 as well. The C-terminal split-parts of Venus-YFP and Cerulean CFP were not directly fused to the transmembrane-region. To get a little bit more flexibility in binding to the N-terminal part a Split Fluorophor-linker was assembled in between.<br><br> | The whole receptor construct consists out of a signalpeptide, an extracellular receptor domain, a GGGS-linker followed by transmembrane region and an intracellular split-reporter-protein. The signalpeptide-sequence according to the EGF-receptor erbb1 ensures the transport of the protein construct to the cytoplasmamembrane. A GGGS-linker is necessary to create a distance between membrane and the recognition-site to overcome cell surface structures as glycoproteins and glyclipids. The sequence of the transmembrane region is taken from the EGF-receptor erbb1 as well. The C-terminal split-parts of Venus-YFP and Cerulean CFP were not directly fused to the transmembrane-region. To get a little bit more flexibility in binding to the N-terminal part a Split Fluorophor-linker was assembled in between.<br><br> | ||
Almost all parts were ordered by genesynthesis in a pMA-vector system which is adapted for cloning BioBrick parts. All possible variations of the receptor constructs were fused together in the pMA-vector and afterwards inserted into a transfectionvector. | Almost all parts were ordered by genesynthesis in a pMA-vector system which is adapted for cloning BioBrick parts. All possible variations of the receptor constructs were fused together in the pMA-vector and afterwards inserted into a transfectionvector. | ||
- | The transfectionvector is a BioBrick | + | The transfectionvector is a BioBrick 2006 part from the Ljubljana, Slovenia team([http://partsregistry.org/Part:BBa_J52017 BBa_J52017]) and includes a kanamycin and ampicillin resistance cassette. There is a pMB1 Ori and the multiple cloning site consist out of the BioBrick Prefix and Suffix restriction enzymes (Prefix: EcoRI, NotI, XbaI/ Suffix: SpeI, NotI, PstI) followed by an eukaryotic terminator sequence. To achieve a strong expression a constitutive promoter construct was needed. Because of this Cytomegalovirus [CMV] promotor was amplified by PCR using the BioBrick part [http://partsregistry.org/Part:BBa_J52038 BBa_J52038 ]from the 2006 Ljubljana, Slovenia team as well and primers below-mentioned. The forward primer bound in the iGEM-prefix, while reverse primer bound at the end of the CMV-coding region. The reverse primer also contained an overhang to get the iGEM-suffix directly to the end of the promoter sequence which later allowed the cloning into the transfectionvector. CMV promoter was cloned into the vector by using the EcoRI and PstI restriction sites. To test the expression activity of the vector with CMV promoter the gene of the yellow fluorescent protein [YFP] was cloned behind the promoter region by using XbaI, PstI restriction enzymes for the YFP insert and SpeI, PstI for the vector to open Biobrick suffix. The tranfsfection of the resulting plasmid into 293T cells shows fully functionality.<br> |
An overview about the cloning is given in table 1<br> | An overview about the cloning is given in table 1<br> | ||
<br><br> | <br><br> |
Revision as of 13:55, 29 October 2008
_cloning strategy
IntroductionTo form different types of synthetic receptor constructs a principle of a building set was used. There were two different parts for an extracellular binding protein (scFv anti NIP, Lipocalin) and four different components of an intracellular signal transduction reporter protein, Cerulean CFP, Split Venus YFP, β-Lactamase and Luciferase. These reporters were used as Split-proteins to achieve that there is only detection when two receptors come together and form a cluster. With this strategy a signal is only given by two binding-molecules which are next to each other as it is realized in the DNA-origami structure or the NIP and Fluorescein coupled BSA.
Table1_cloning strategy overview about the cloning steps to create the different types of synthetic receptors. To get further information about the composit parts see https://2008.igem.org/Team:Freiburg/Parts
Step 1 Vector digestion: EcoRI + PstI Insert
digestion: EcoRI + PstI BBa-J52017 _CMV-promotor Step
2 Vector digestion: AgeI+SpeI Insert
digestion: NgoMIV+SpeI pMA-BBFR
_ SPLIT-Linker C-YFP C-CFP Step
3 Vector digestion: AgeI+SpeI Insert
digestion: NgoMIV+SpeI pMA-BBFR
_egfR-Tm _ N-β-Lactamase _ C-β-Lactamase _ SPLIT-Linker_ C-YFP _ N-YFP _ SPLIT-Linker_ C-CFP _ N-CFP _ BB058 (Luciferase) _ BB057 (Luciferase) Step
4 Vector digestion: AgeI+SpeI Insert
digestion: NgoMIV+SpeI pMA-BBFR
_SP _scFv-anti-NIP _ Lipocalin Step
5 Vector digestion: AgeI+SpeI Insert
digestion: NgoMIV+SpeI pMA-BBFR
_SP_ scFv-anti-NIP and pMA-BBFR-+SP_ Lipocalin _GGGS-linker (produced by Klenow fill in) Step
6 Vector digestion: AgeI+SpeI Insert
digestion: NgoMIV+SpeI pMA-BBFR
_SP_ scFv-anti-NIP _ GGGS-Li and pMA-BBFR
_ SP_ Lipocalin _ GGGS-Li _
egfR-Tm _ N-β-Lactamase _
egfR-Tm _ C-β-Lactamase _
egfR-Tm _ SPLIT-Linker_ C-YFP _
egfR-Tm _ N-YFP _
egfR-Tm _ SPLIT-Linker_ C-CFP _
egfR-Tm _ N-CFP _
egfR-Tm _ BB058 (Luciferase) _
egfR-Tm _ BB057 (Luciferase) Step
7 Vector digestion:
SpeI + PstI Insert
digestion: XbaI + PstI BBa-J52017_CMV _SP_ scFv-anti-NIP_GGGS-Li_egfR-Tm_N-β-Lactamase _ SP_ scFv-anti-NI _GGGS-Li_ egfR-Tm_C-β-Lactamase _ SP_ scFv-anti-NIP_GGGS-Li_
egfR-Tm_SPLIT-Linker_C-YFP _ SP_ scFv-anti-NIP_GGGS-Li_ egfR-Tm_N-YFP _ SP_ scFv-anti-NIP_GGGS-Li_
egfR-Tm_SPLIT-Linker_C-CFP _ SP_ scFv-anti-NIP_GGGS-Li_ egfR-Tm_N-CFP _ SP_ scFv-anti-NIP_GGGS-Li _ egfR-Tm_BB058 (Luciferase) _ SP_ scFv-anti-NIP_GGGS-Li _ egfR-Tm_BB057 (Luciferase) _ SP_ Lipocalin _GGGS-Li_ egfR-Tm_N-β-Lactamase _ SP_ Lipocalin _GGGS-Li_ egfR-Tm_C-β-Lactamase _ SP_ Lipocalin _GGGS-Li_
egfR-Tm_SPLIT-Linker_ C-YFP _ SP_ Lipocalin _GGGS-Li_
egfR-Tm_N-YFP _ SP_ Lipocalin _GGGS-Li_
egfR-Tm_SPLIT-Linker_ C-CFP _ SP_ Lipocalin _GGGS-Li_
egfR-Tm_N-CFP _ SP_ Lipocalin _GGGS-Li__ egfR-Tm _ BB058 (Luciferase) _ SP_ Lipocalin _GGGS-Li__ egfR-Tm _ BB057 (Luciferase) The cloning was started with a preparative digestion of the DNA-Plasmids. To clone fusion parts the vector constructs were digested with AgeI and PstI to open the Biobrick suffix. The inserts were digested with NgoMIV and PstI. For cloning into the transfection-vector the enzymes SpeI and PstI were used for vector and XbaI, PstI for insert to keep up the ATG-start codon in the XbaI restriction site of the biobrick suffix. All restriction-enzymes were ordered from New England Biolabs. After digestion the DNA-fragments were separated on a 1% agarose gel. The DNA-band of interest was isolated and purified with the QIAGEN QIAquick Gel Extraction Kit. For the ligation a 3 molar excess of the insert was put together with the vector-fragment and ligated with a Quick ligase (New England Biolabs). After half an our at room temperature the DNA was transformed to chemical competent E.coli strain XL1 cells, plated on 2YT-agar-plates and incubated at 37°C over night. After picking clones and growing in 5ml LB-medium, the plasmid DNA was isolated by QIAGEN QIAprep Spin Miniprep Kit. A test digestion was prepared with about 0,5µg Plasmid DNA and NotI restriction enzyme to isolate the fusion-protein from the vector and to control if the expected bands were obtained. After a positive result the clones were sent to GATC-Biotech for sequencing.
The GGGS-Linker was produced by Klenow -fill-in-PCR. Two primers were designed align to each other at 60°C and filled to a complete dobble-strand by Klenow Polymerase fragment. The present BioBrick prefix and suffix rules are not compatible with modular protein design. Thus as in 2007, we propose an extension of the present standard for fusion proteins in which two restriction sites are added in frame adjacent to the coding sequence. The basic parts and as well all composite parts follow this strategy.
To get further information see [http://parts.mit.edu/igem07/index.php/Freiburg07/report_fusion_parts FreiGEM07_report_fusion_part] The cloning parts scFv-anti-NIP, lipocalin-FluA, Split-Venus-N-YFP, Split-Venus-C-YFP, Cerulean-N-CFP and Cerulean-C-CFP were obtained by genesynthesis and ordered by the GENEART company. The β-Lactamase fragments were adopted from genesynthesis GENEART order in 2007. The erbb1-transmembrane, Split-Fluorophor-Linker and the erbb1-signalpeptide were synthesized by ATG:biosynthetics. The CMV promoter cloning part was produced by PCR with the template J52038 using the CMV_RLuc_Forward-primer and CMV_RLuc_Reverse-primer. To synthesize the GGGS-linker a Klenow-fill-in-reaction was performed by using Klenow-fragment without exonuclease activity and GGGS-forward and reverse primer. |