Appeal No. 2006-1270 Page 5
Application No. 10/222,614
recombination was known in any other human stem cell at the time of its
publication. Id. at 5.
The examiner also states that
[t]he prior art does not show human stem cells with zinc finger-
endonuclease fusion proteins, the prior art therefore does not
predict whether such cells could be made or used. Hatada [ ]
shows that stem cells are difficult to isolate, Hanson [ ] shows that
hematopoeitic stem cells are difficult to purify and manipulate, and
Zwaka [ ] show[s] that human embryonic stem cells are difficult to
manipulate.
Id.
As noted by appellants, see Appeal Brief,6 page 5, the Hatada and Zwaka
references relate to homologous recombination, and the claims are not limited to
cells containing two engineered zinc finger proteins that also comprise an
endonuclease, that are required to undergo homologous recombination. Cells
comprising a single zinc finger-nuclease fusion protein, appellants assert citing
Chandrasegaran, “were known to be useful in mutagenesis, targeted cleavage,
gene expression, detection of conformational changes in nucleic acid and
targeted recombination.” Reply Brief, page 4. Thus, Hatada and Zwaka, as they
relate to the frequency of homologous recombination in human stem cells, are
not relevant to the issue of whether claims 123 and 124 are enabled by the
specification. Moreover, while Zwaka teaches that electroporation protocols that
have been developed for mouse embryonic stem cells do not achieve the same
results in human embryonic stem cells, see id., abstract, the reference teaches
further that “[f]or human embryonic stem cells, the best chemical reagents yield
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