Plasmid 12251: pMDLg/pRRE
  • 3rd generation lentiviral packaging plasmid; Contains Gag and Pol; also requires pRSV-Rev (Addgene#12253) and envelope expressing plasmid (Addgene#12259)


  • pMD
    (Search Vector Database)

  • Mammalian Expression, Lentiviral ; Packaging

  • 8895

  • CMV Fwd List of Sequencing Primers

  • Ampicillin

  • DH5alpha

  • 37

  • High Copy

  • View sequences (7)
  • View map

  • Notes from Addgene (1)

  • Didier Trono



This 3rd generation LV packaging plasmid includes gag, coding for the virion main structural proteins; pol, responsible for the retrovirus-specific enzymes; and RRE, a binding site for the Rev protein which facilitates export of the RNA from the nucleus. This plasmid does not include Rev. The third generation packaging system offers maximal biosafety but is more cumbersome, as it involves the transfection of four different plasmids in the producer cells.
Example of a 3rd generation packaging combo: pMDLg/pRRE + pRSV-Rev + pMD2.G.

Please note that most Trono lab lentivectors contain a wt 5'LTR and can be packaged only using the 2nd generation packaging system (as the wt 5'LTR requires TAT for activation).
If you wish to use the 3rd generation packaging system, you need to have a lentivector with a chimeric 5'LTR (e.g. CCL-, RRL-, etc) in which the HIV promoter is replaced with CMV or RSV, thus making it TAT-independent. The lentivectors carrying the chimeric 5'LTR can be packaged into either a 2nd or 3rd generation packaging system.

Please note that the full sequence for this plasmid is approximated and not fully verified. Please visit the Trono lab http://tronolab.epfl.ch for cloning strategies, protocols, publications, and more. See LentiWeb http://www.lentiweb.com for discussions on cloning strategies and protocols.

Please note that the ClaI site in this plasmid is blocked by Dam methylation. Do not use this enzyme for diagnostic digests.

Addgene has sequenced a portion of this plasmid for verification. Full plasmid sequence is available only if provided by the depositing laboratory.

Article: A third-generation lentivirus vector with a conditional packaging system. Dull et al (J Virol. 1998 Nov . 72(11):8463-71. PubMed)

Please acknowledge the principal investigator and cite this article if you use this plasmid in a publication. Also, please include the text "Addgene plasmid 12251" in your Materials and Methods section.