Appeal No. 2006-1270 Page 4
Application No. 10/222,614
an undue amount of experimentation to make and/or use the claimed cells,
wherein the cells are stem cells. See Examiner’s Answer, pages 3-6.
The examiner notes that there are no working examples, and that the
“specification provides guidance to use zinc finger-endonuclease fusion proteins
as gene regulators . . . and as transcription repressors . . . without further
elaboration as to how such functions can be achieved.” Id. at 4. Those are
issues that would seem to apply to the use of any cell type, not just stem cells,
and the examiner does not explain how those issues provide more of an
impediment to the use of stem cells as opposed to other cell types.
With respect to stem cells, the examiner focuses on the use of the zinc
finger-endonuclease constructs in homologous recombination in stem cells. See
id. at 4. The examiner cites Hatada3 for the proposition “that hematopoietic stem
cells have not been shown to perform homologous recombination.” Id. Hanson4
is cited for demonstrating that “hematopoietic stem cells are difficult to purify and
manipulate.” Id. at 4-5. Finally, Zwaka5 is cited for the discussion that “human
embryonic stem cells are more difficult to manipulate than prior art mouse
embryonic stem cells,” and that it does not appear that homologous
3 Hatada et al. (Hatada), “Gene correction in hematopoietic progenitor cells by homologous
recombination,” PNAS, Vol. 97, No. 25, pp. 13807-811 (2000).
4 Hanson et al. (Hanson), “Enhanced green fluorescent protein targeted to the Sca-1 (Ly-6A)
locus in transgenic mice results in efficient marking in hematopoeitic stem cells in vivo,”
Experimental Hematology, Vol. 31, pp. 159-67 (2003).
5 Zwaka et al. (Zwaka), “Homologous recombination in human embryonic stem cells,” Nature
Biotechnology, Vol. 21, pp. 319-21 (2003).
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