Hi All,
This news holds potential for all of us to become Jim Finn's kin...
Industry's First Reproducible Cloning of Pigs Reported in
'Nature Biotechnology'
- New Cloning Technique Offers Greater Potential for Use in
Xenotransplantation Than Earlier Reports -
DEFOREST, Wis., Sept. 27 /PRNewswire/ -- Two litters of ``cloned'' pigs
have been successfully produced using nuclear transfer (NT) and more litters
are on the way, demonstrating the commercial feasibility of porcine cloning.
The NT technique described in the October 2000 issue of ``Nature
Biotechnology'' greatly improves prospects for the genetic manipulation of
pigs to provide organs and tissues for transplantation. The report is
co-authored by scientists from Infigen, Inc., a privately held biotechnology
company in DeForest, WI., and Imutran, Ltd., a UK-based subsidiary of
Novartis Pharma AG. The Infigen/Imutran protocol has produced two litters,
each of two male piglets, born in July and September.
Somatic cells that were cultured for periods of eight and twenty-two days
were fused with enucleated oocytes to produce the embryos that developed
into the two litters. In this NT process the genetic material, contained
in the nucleus, is transferred from the somatic cell to the oocyte and its
developmental potential is ``reprogrammed.'' Currently, multiple pregnancies
are ongoing, derived from donor cells that have been cultured for up to
ninety days. This ability to culture the donor cells for extended periods
is a prerequisite for gene transfer and gene targeting strategies.
``The publication recognizes the industry's first successive litters of
cloned pigs, animals which hold enormous promise as a source of new treatments
for millions of people suffering from advanced diseases of numerous types,''
said Michael Bishop, Ph.D., President of Infigen, and corresponding author
of the paper.
``Our optimized nuclear transfer approach offers the first reproducible
means for producing these valuable animals for xenotransplantation, as well
as the production of pharmaceutical proteins, and the enhancement of pig
breeding programs worldwide.''
Past research has demonstrated that pig organs -- eg, kidneys, hearts,
lungs, liver and other tissues -- are immunologically incompatible with
humans. A hyperacute rejection reaction is stimulated by certain human
antibodies specific for a sugar structure (Gal-alpha-1,3-Gal epitope) on
the surface of pig endothelial cells. ``Knock-out'' or deletion of the gene
that creates this epitope has not been possible in pigs to date. It is
hoped that the ``knock-out'' of this epitope, when combined with Imutran's
proprietary genetic modifications, will lead to extended survival times for
porcine xenotransplants.
Simon Thompson, Ph.D., of Imutran and co-author of the paper, stated that
the somatic cell nuclear transfer process described in the ``Nature
Biotechnology'' report is ``promising progress towards knocking-out pig
genes,'' enhancing the prospects for overcoming immune rejection in a human
recipient.
``In the mouse it is possible to make very precise modifications to the
genome, including the inactivation of genes or groups of genes by gene
targeting. The nuclear transfer procedure described in this paper is a
significant step towards gene targeting in the pig, which can be employed
to develop tissues and organs for transplantation,'' said Dr. Thompson.
Infigen/Imutran researchers anticipate that the extended culture of donor
cells for nuclear transfer -- described for the first time in the ``Nature
Biotechnology'' report -- will offer important advantages for the
development of porcine xenografts:
* More efficient generation of transgenic pigs, through the evaluation
of the transgene integration site during the cell culture phase,
rather than following establishment of a transgenic line.
* Potential for gene targeting to delete genes that contribute to
organ rejection or to improve safety.
The report, ``Production of cloned pigs from in vitro systems,'' was
published in the October 2000 issue of ``Nature Biotechnology'' (vol. 18).
In addition to Drs. Bishop and Thompson, coauthors included J. Betthauser,
E. Forsberg, M. Augenstein, L. Childs, K. Eilertsen, J. Enos, T. Forsythe,
P. Golueke, G. Jurgella, R. Koppang, T. Lesmeister, K. Mallon, G. Mell,
P. Misica, M. Pace, M. Pfister-Genskow, N. Strelchenko, G. Voelker,
and S. Watt, all of Infigen, Inc.
http://biz.yahoo.com/prnews/000927/wi_infigen.html
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