Product Code: OG108R1
Product Code: OG108C1
Product Code: OG108G1

Product Description

TOPO multiple cloning site CMV expression vector. This vector is modified to contain the restriction enzyme pattern from the cloning plasmid TOPO.

Plasmid Information

Product Name: pSF-CMV-TOPO

Product Code: OG108

Size (bp): 4343 bp

Bacterial Antibiotic Selection: AmpR

Origin and Compatibility: pUC high copy derived from pBR322

Bacterial Copy Number: 500-700 per cell

Promoter: Cytomegalovirus (CMV) immediate early promoter

Plasmid Purpose:

A versatile cloning plasmid for the expression of genes in mammalian cells. This plasmid contains the multiple cloning site (MCS) from Life Technologies TOPO vector however it has been modified slightly to accommodate some restriction sites in the SnapFastTM system. These changes are described in the full plasmid details PDF. The use of this MCS instead of the normal SnapFastTM vector MCS will limit the ability to use some of the inserts that we sell that immediately flank or are inserted within the standard MCS. In this vector these limitations mainly extend to NcoI aligned peptide tags and signal peptides however these same inserts can still be ligated into the NotI and HindIII sites in this MCS. Most other inserts should still be compatible with this plasmid. TOPO is a registered trademark of Life Technologies.

Promoter Expression Level:

This plasmid contains the mammalian CMV promoter to drive gene expression. We have tested all of our mammalian promoters in a range of cell types and CMV is consistently the strongest in those we have studied. However there are many reports of the CMV promoter demonstrating silencing by methylation in long-term culture. For this reason we stock a range of other promoters that are compatible with this plasmid and are available on request.

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Transcription Termination:

This plasmid contains three alternative transcription terminators for mammalian bacterial and bacteriophage (T7) expression. This means that only the promoter needs to be changed to alter the expression system you are using. We sell multiple promoters that can be used in each of these systems. The presence of each terminator does not reduce expression in the alternative systems.

Multiple cloning site notes:

This vector contains a different multiple cloning site (MCS) from the standard SnapFastTM vector. The MCS is derived from TOPO. The order of the restriction sites in this vector are almost the same as in TOPO however the sequence is not. The TOPO MCS has also been modified as follows:

  • The Afl II site the second EcoRI site the PstI sites have been removed to allow compatibility with as many of our products as possible.
  • The NotI site that is normally in this MCS has been replaced with a PspOMI site which has compatible cohesive ends with NotI digested fragments when cleaved. The NotI has been moved to the 5 prime of the multiple cloning site as this allows the use of many of our 5 prime coding sequences and tags.
  • The XbaI site has been moved downstream by one restriction site.
  • The BamHI site that is normally found in all SnapFastTM vectors (in the downstream fusion MCS) has been replaced with a BclI site because the TOPO MCS contains this site. BamHI and BclI produce compatible cohesive ends when cleaved although BclI is methylated in this vector and will require growth in a Dam methylase negative bacterial strain (such as JM110 cells) before it can be used.
  • In the normal version of this multiple cloning site an NsiI site can be found at the 5 prime. However this site contains a start codon and so it has been ablated to prevent premature ribosomal translation initiation.
The ClaI to NheI sites have other functions such as adding peptide tags or IRES elements. The BsgI and BseRI restriction sites cleave within the stop codon in the XbaI site and allow the retrospective fusion of coding sequences. These sites are normally only used on genes that we sell in the main multiple cloning site. This concept is explained in more detail on our website using the drop down box on the homepage and selecting: Fuse a coding sequence to the 3 prime end of a gene already in the SnapFast plasmid.

Intellectual Property Status

This product is part of our SnapFastâ„¢ plasmid range, for more information on the intellectual property status of this plasmid please click here. For more information on the terms of our licences please click here.