Plasmid 20923: pEP4 E02S EM2K
  • used in the derivation of human iPS cells using non-integrating episomal vectors; expresses Oct4 and Sox2; Myc and Klf4

  • Oct4 and Sox2; Myc and Klf4

  • 2700

  • H. sapiens (human)

  • NM_002701 NM_004235 NM_002467 NM_003106

  • SOX2 (ANOP3, MCOPS3)
    KLF4 (RP11-150J11.1, EZF, GKLF)
    MYC (MRTL, MYCC, bHLHe39, c-Myc)

  • pCEP4
    (Search Vector Database)

  • Invitrogen

  • Episomal/EBNA

  • 12600

  • multiple

  • Unknown

  • multiple

  • Unknown

  • na List of Sequencing Primers

  • Ampicillin

  • Top10F'

  • 37

  • Top10 "Extremely" low copy number

  • Low Copy

  • View sequences (8)
  • View map

  • James Thomson



Oct4 and Sox2 are coexpressed under a strong EF promoter. Myc and Klf4 are coexpressed under a separate (but identical) EF promoter. This plasmid contains EBNA-1 and OriP for limited maintenance in mammalian cells.

These plasmids were used at concentrations of >1.5 mg/ml. When preparing these plasmids for transfection, 3 low concentration maxipreps are done and the elution is combined in about 700 ul.

Note that this a K278M mutation in Klf4, but it does not affect the reprogramming ability.

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

Article: Human Induced Pluripotent Stem Cells Free of Vector and Transgene Sequences Yu et al (Science. 2009 Mar 26. 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 20923" in your Materials and Methods section.