Supplementary Material For:
Multipurpose modular lentiviral vectors for RNA interference and transgene expression
Molecular Biology Reports
Venu Kesireddy, Peter FM Van der Ven, Dieter O Fürst
Department of Molecular Cell Biology, Institute for Cell Biology, University of Bonn, Bonn, Germany
Corresponding author:
Dieter O. Fürst, Institute for Cell Biology, University of Bonn
Ulrich-Haberland-Str. 61a,D-53121 Bonn
Tel: +49-228-73-5301; Fax: +49-228-73-5302; E-mail:
Supplementary methods
Construction of pLVmir
First, the vector pLVCT-tTRKRAB was cut with the restriction enzyme SpeI to give two fragments 4372 bp and 8505 bp respectively (Figure S1). The 8505 bp fragment was self- ligated to yield a new vector pLVCT∆(SpeI-SpeI). The XhoI site just upstream of the TetO sequence was deleted by digesting with XhoI, blunting the resulting sticky ends and finally religating to generate the plasmid pLVCT∆(SpeI-SpeI)∆XhoI. In the next step, the shRNAmir-WPRE portion from the vector pGIPZ was amplified and cloned into the plasmid pLVCT∆ (SpeI-SpeI) ∆XhoI using the SpeI and MscI restriction sites in forward and reverse orientation (see the list of primers in Table S2), to generate a new plasmid, which was named pLVmir. This plasmid harbors unique XhoI, EcoRI and MluI sites to facilitate direct cloning of miRNA30- based short hairpin sequences from Open Biosystems (1). To further simplify the cloning protocol, a stuffer sequence of 4.3 kb was introduced into the XhoI and EcoRI sites. We named the final version of the vector ‘pLVmir-stuffer’. A schematic representation of the cloning is shown in Figure S1. The resulting vector including its unique restriction sites and modules is given in Figure 1.
Two-step protocol for constructing modular vectors based on pLVmir
The protocol is illustrated for cloning shRNAmir sequences targeting mouse Xirp2 mRNA (NM_001024618.2). In the first step of the two step protocol, sequences predicted to target Xirp2 mRNA were selected based on the siDESIGN algorithm (Dharmacon, Lafayette, USA) and converted to shRNAmir sequences with XhoI and EcoRI ends using a previously published protocol (2). shRNAmir sequences were double digested with XhoI and EcoRI enzymes and cloned into the correspondingly prepared pLVmir-stuffer. The successful cloning removes the stuffer sequence (4.3kb) and introduces a short fragment of 110 bp consisting of the hairpin sequence. Alternatively, shRNAmir clones from pSM2 (retroviral) or pGIPZ (lentiviral) public libraries can be excised and cloned into pLVmir using the same restriction sites.
In the second step, the NotI +SpeI double digested fragment of pLVTHM (the 3184bp shorter fragment also designated as module IA, Figure 2) was cloned into correspondingly prepared pLVmir harboring the hairpin sequence (from step one) to generate a lentiviral vector pLVET-mir, constitutively expressing GFP and the cloned shRNAmir sequence under the control of the EF1-alfa promoter. Repeating the same step with NotI+ SpeI double digested fragment of pLVET-tTRKRAB (the 4811 bp, shorter fragment also designated as module IB, Figure 2) generated a lentiviral vector (pLVET-tTRKRAB mir or pLVET-Kmir) conditionally expressing GFP and the cloned shRNAmir sequence under the control of the same promoter. The tTRKRAB module confers conditionality to the system (3).The EF1-alfa promoter could be exchanged with the CAG promoter in both constitutive and conditional versions by cutting and replacing the NotI+ PacI fragment in these vectors with that of pLVCT-tTRKRAB . Alternatively, a 4372 bp, SpeI digested fragment ( FigureS1) of pLVCT-tTRKRAB could be replaced back into pLVmir containing the cloned shRNAmir sequence from step one by using the single SpeI restriction site and selecting clones containing the 4732 bp insert in the right orientation to give pLVCT-mir or pLVCT-Kmir versions. The Tet-off version, pLVCT-rtTRKRAB-2SM2 could be generated following the same protocol.
Construction of pLVTHM-mir
A new plasmid pLVTHM-mir was constructed based on pLVTHM backbone for expression of shRNAmir’s from H1 promoter as described in the steps below.
Step1: Deletion of SalI site at position 2028 in pLVTHM
The SalI site present just upstream of EF1 alpha promoter in pLVTHM was destroyed by digesting with SalI, blunting the resulting sticky ends and religating to give a new plasmid pLVTHM∆SalI.
Step 2: Introduction of a new SalI site between MluI and ClaI sites.
A small stuffer sequence (Des tail, the c-terminal portion of Desmin, NM_001927.3) was amplified with a forward primer containing a MluI site and a reverse primer containing both SalI and ClaI sites (see the list of primers in Table S2). The above amplicon was cloned into MluI and ClaI sites in pLVTHM∆SalI resulting in a further new plasmid mpLVTHM∆SalI, with a new SalI site introduced between MluI and ClaI.
Step 3: Cloning miR30 sequence
The miR30 sequence from the vector pSM2 (1) was amplified with forward primer containing MluI site and a reverse primer containing SalI site (see the list of primers in Table S2) and cloned into MluI and SalI sites in mpLVTHM∆Sal to give the new vector, pLVTHM-mir.
Construction of pLVTU6+1
The U6-shRNA cassette from the plasmid pTZU6+1 (4) was transferred to pLVTHM∆SalI∆XbaI using the EcoRI and ClaI sites to give the new plasmid pLVTU6+1 which can be used for expression of shRNA from the U6 promoter.
Construction of pLVTU6-mir
The U6-shRNA mir cassette from pSM2 was transferred to pLVTHM ∆Sal using BamHI (blunted) and MluI sites on the former and EcoRI (blunted) and MluI sites on the latter, to create a new plasmid pLVTU6-mir which can be used for expression of shRNAmir from the U6 promoter.
Construction of constitutive and conditional transgene modules
The Actin-GFP sequence from pMypG vector (5) was transferred to pLVCT-tTRKRAB using MluI and XbaI (blunted) on pMypG and MluI and SmaI sites on pLVCT-tTRKRAB to give the conditional version of transgene module i.e. pLVCT-Actin-GFP-tTRKRAB (Module ID with GOI being ACTA1, NM_001100.3). Digesting the conditional version with EcoRI and self-ligating the larger fragment yields the constitutive version of the transgene module (Module IC with GOI being ACTA1). Constitutive version of the vector can be used to clone any gene by replacing Actin sequence using (PmeI/BamHI/MluI) and SalI sites.
Figure S1. Schematic representation of the cloning steps performed to construct the vectorpLVmir from pLVCT-tTRKRAB and pGIPZ.
Figure S2. Schematic diagram showing the designing and cloning of shRNAmirs.
A
A) In the first step, a 22 nucleotide sense sequence that can potentially target the mRNA of a gene underconsideration is identified with siDESIGN algorithm( A 97 base single strand is designedbased on RNAi oligo retriever ( as shown in Figure. Universal primers with XhoI and EcoRI in forward and reverse direction respectively amplify thesingle strand DNA to a double strand. The resulting amplicon is double digested with theseenzymes and cloned into pLVmir or other compatible vectors. B) Shows the alignment of universalprimers with the 97 base single strand nucleotide.
Table S1. Compatible vectors for cloning into Pol III modular vectors
Source vector / Expression cassette from source vector / Target vector / Expression cassette replaced from target vectorpSUPER / EcoRI-ClaI (H1-shRNA) / pLVTHM orpLVTHM-mir * / EcoRI-ClaI (H1-shRNA)
pRSC / EcoRI-XhoI (H1-shRNA) / pLVTHM-mir ** / EcoRI-Sal (H1-shRNAmir)
pSM2 / SalI-MluI (shRNAmir) / pLVTU6-mir / Sal-Mlu (shRNAmir)
pSM2 and pGIPZ / XhoI-EcoRI (hairpin) / pLVmir / Xho-EcoRI (hairpin)
pSUPER is the first plasmid-based vector for shRNA expression (developed at Netherlands Cancer Institute (NKI)) and one of the popular vectors in the scientific community (6).
pRSC (Retro Super Cam) is a retroviral library vector developed at NKI. The NKI library targets about 8000 human genes and 15000 mouse genes with 3 or 2 shRNA constructs per gene, respectively.
Hannon-Elledge libraries are second generation libraries utilizing shRNAmir design instead of shRNA design. These libraries include both pSM2 (Retroviral library) and pGIPZ (Lentiviral library) and are marketed by Open Biosystems and cover 30,000 human and 30,000 mouse genes with 3 constructs per gene.
In pSM2 vectors shRNAmir is driven by a U6 (Pol III) promoter whereas in pGIPZ vectors shRNAmirs are driven by CMV (Pol II) promoter.
Although the Hannon-Elledge library also exists as conditional vectors (Tet-repressor system), the system only allows for control of a Pol II promoter and the system tends to be leaky.
*The H1-shRNA cassette from pSUPER can also be cloned into pLVTHM-mir using the same EcoRI-Cla sites. In this case the H1- shRNA casette from pSUPER replaces the H1-shRNAmir cassette in pLVTHM-mir.
**XhoI and SalI sites are compatible and the H1- shRNA casette from pRSC replaces the H1-shRNAmir cassette in pLVTHM-mir.
Table S2. Primers used for constructing the modular vectors
pLVmirmiRNA30_speI_fw / 5'-TTTACTAGTTGAGTTTGTTTGAATGAGGCT-3'
WPRE_MscI_rev / 5'-TTTTGGCCAATTAATTCCAGGCGGGGAGG-3'
pLVTHM-mir
Des Tail rv Sal-ClaI / 5'-TTTTTATCGATGTCGACGAGCACTTCATGC-3'
miRNA30_Mlu_fw / 5'-TTTACGCGTTAGGGATAACAGGGTAATTG-3'
miRNA30_Sal_rv / 5'-TTTGTCGACGCATTAGTCTTCCAATTGA-3'
Universal Primers
miR30PCRXhoIF / 5'-CAGAAGGCTCGAGAAGGTATATTGCTGTTGACAGTGAGCG-3'
miR30PCREcoRIF / 5'-CTAAAGTAGCCCCTTGAATTCCGAGGCAGTAGGCA-3'
Table S3. Primers suggested for sequencing the shRNAmir/shRNA hairpins in the modular vectors
Vector / Name / SequencepLVmir / WPRE_rev / 5'-GACAGCAACCAGGATTTATA-3'
pLVTHM-mir / H1-F / 5'-GCATGTCGCTATGTGTTCTGGG-3'
pLVTU6+1 / pLVTHM-FN / 5'-ATGGGATCAATTCACCATGC-3'
Table S4. Primers used for qRTPCR
Name / SequenceXirp2_ RT_1f / 5'-GCAGCTTCTCGGCTAATGTCA-3'
Xirp2_RT_1r / 5'-AGGCGTTGCAGGTTGAAGTC-3'
Gapdh_RT_1f / 5'-AGGTCGGTGTGAACGGATTTG-3'
Gapdh_RT_1r / 5'-TGTAGACCATGTAGTTGAGGTCA-3'
Table S5: shRNAmir sequences targeting mouse Xirp2 mRNA.
-----common------sense------loop------
NM_001024618.2 1 TGCTGTTGACAGTGAGCG-CACAGTAAGTGTCAATGAAATA-TAGTGAAGCCACAGATGTA 59
NM_001083919.1 1 TGCTGTTGACAGTGAGCG-CCGCTGTCAGATGTGGAAATTA-TAGTGAAGCCACAGATGTA 59
NM_152381.4 1 TGCTGTTGACAGTGAGCG-AGGATGGAGTTTAATGACCATA-TAGTGAAGCCACAGATGTA 59
------antisense------common----
NM_001024618.2 60 TATTTCATTGACACTTACTGTT-TGCCTACTGCCTCGGA 97 (mir1Xirp2)
NM_001083919.1 60 TAATTTCCACATCTGACAGCGA-TGCCTACTGCCTCGGA 97 (mir2Xirp2)
NM_152381.4 60 TATGGTCATTAAACTCCATCCC-TGCCTACTGCCTCGGA 97 (mir3Xirp2K)
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SUPPLEMENTARY REFERENCES
1.Chang, K., S.J. Elledge, and G.J. Hannon. 2006. Lessons from Nature: microRNA-based shRNA libraries. Nat Methods 3:707-714.
2.Paddison, P.J., M. Cleary, J.M. Silva, K. Chang, N. Sheth, R. Sachidanandam, and G.J. Hannon. 2004. Cloning of short hairpin RNAs for gene knockdown in mammalian cells. Nat Methods 1:163-167.
3.Szulc, J., M. Wiznerowicz, M.O. Sauvain, D. Trono, and P. Aebischer. 2006. A versatile tool for conditional gene expression and knockdown. Nat Methods 3:109-116.
4.Lee, N.S., T. Dohjima, G. Bauer, H. Li, M.J. Li, A. Ehsani, P. Salvaterra, and J. Rossi. 2002. Expression of small interfering RNAs targeted against HIV-1 rev transcripts in human cells. Nat Biotechnol 20:500-505.
5.Salmikangas, P., P.F. van der Ven, M. Lalowski, A. Taivainen, F. Zhao, H. Suila, R. Schroder, P. Lappalainen, et al. 2003. Myotilin, the limb-girdle muscular dystrophy 1A (LGMD1A) protein, cross-links actin filaments and controls sarcomere assembly. Hum Mol Genet 12:189-203.
6.Brummelkamp, T.R., R. Bernards, and R. Agami. 2002. A system for stable expression of short interfering RNAs in mammalian cells. Science 296:550-553.
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