Appeal No. 2006-1270 Page 8
Application No. 10/222,614
different target sites. Now that the claims have been construed, we now turn our
attention to review of the obviousness rejection.
Brenneman is cited for disclosing “that the efficiency of homologous
recombination in a human cell can be increased by digestion by an endonuclease
at the site of homology.” Examiner’s Answer, pages 6-7. Brenneman specifically
teaches that Xba I endonuclease, as well as the rare-cutting yeast endonuclease
PI-Sce I increased the frequency of recombination, whereas restriction enzymes
that cut outside of the repeated regions or between them “produced no change in
recombination frequency.” Brenneman, abstract. The examiner notes that
“Brenneman [ ] does not show use of a chimeric nuclease that comprises a zinc
finger protein.” Examiner’s Answer, page 7.
Chandrasegaran is cited for disclosing “bacterial cells transformed with a
fusion protein of a three-zinc finger DNA binding domain linked to a catalytic
nuclease domain of Fok I.” Id. Chandrasegaran is also cited for teaching that
each finger of the zinc finger protein binds to three nucleotides of a
polynucleotide, and that zinc finger proteins may be designed to bind a series of
triplet nucleotides of choice. See id.
The examiner concludes:
It would have been obvious to a person of ordinary skill in
the art at the time the invention was made to modify the
endonuclease used by Brenneman [ ] by use of the chimeric zinc
finger-Fok I endonuclease of Chandrasegaran because use of the
endonuclease of Chandrasegaran allows for cleavage at other
repeated sites of choice and would thereby increase the frequency
of homologous recombination at the sites of choice.
Recombination at repeated sites of choice would further enable
generation of desired recombination products and allow for further
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