Retroviral Vectors with Integrated oriP/EBNA1 for IPSC

The new product of the week of Sep 21-27 is the retrovirus plasmid sets that contain a built-in episomal expression system. As we have discussed previously, OriP/EBNA1 system originated from Epstein-Bar virus, which allows the establishment of stable episomes at 5-20 copies per cell, and duplication once per cell division.

By using the oriP/EBNA1 episomal system, reprogramming cDNAs can be expressed at prolonged time period in reference to plasmid transfection, without integration into chromosomal DNA. A paper published in PLoS One on Sep 18, 2009 by Marchetto et al. showed that by using such a system (on different plasmids) the authors were able to create induced pluripotent stems cells (iPS cells,) effectively from human embryo neural precursor cells.

The Allele pCHAC-EBNA system has dual functions: it can be ready-to-use plasmids for episomal expression of Oct4, Sox2, c-Myc, Klf4, or Nanog and Lin28 by a simple transfection into target cells; it can also be packaged into retroviruses by transfecting into the Allele Phoenix Retrovirus packaging Eco or Ampho cells. This product group is officially launched today. It should become a highly convenient and unique tool for iPSC-related studies.

Tags: Ampho cells, EBNA, Eco cells, episomal expression, iPS cells, iPSC, iPSCs, New Product of the week, oriP, Phoenix Retroviral System, reprogramming, retroviral vector, retrovirus

What seems to be going on with RNAi related patents in the US

Reciting Table 1 from Ref 1 and Table 3 from Ref 2:

By the end Nov 2008 it appears that Allele’s patent (US 7,294,504 and 7,422,896) are the only currently granted DNA based RNAi patents. The focus of Allele’s technology is siRNA of 21-23, either in separate sense and antisense strands, or shRNA or miRNA format, thus not covered by the Fire patent or the Kreutzer-Limmer patent. Since these RNAi inducers are not synthesized by chemical reactions, or produced with enzymes or cell lysate in vitro, they do not relate to Tuschl I or II patent groups. Allele Biotech can not guarantee that its interpretation is correct or final by any means; commercial user of any of the related technologies should perform own due diligence.

[1] Charlie Schmidt. March 2007 “Negotiating the RNAi patent thicket” Nature Biotechnology 25 (3): 273-275

[2] Dirk Haussecker. May 2008 “The Business of RNAi Therapeutics” Human Gene Therapy 19: 451-462

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Tags: gene silencing, H1, lentiviral vector, miRNA, PCR cassette, plasmid vector, pol III, retroviral vector, RNAi, shRNA, siRNA, U6