Appeal No. 2001-0766 Page 4
Application No. 08/483,941
rejection@ of claims 1, 2, 6, 11, 16, 26 and 36 is set forth at pages 5-7 of the
Examiner’s Answer as follows:
Germann et al. disclose the use of a[n] in-frame chimeric
fusion gene between the genes encoding a dominant selectable
marker and a protein of interest as a simple means of selecting
for eukaryotic cells expressing the protein of interest and the
use of retroviral vectors as the means of introduction of the
chimeric genes into the cells. Germann et al. teach on page
7418, paragraph 1 the advantages of fusing the dominant
selectable gene to the gene of interest in contrast to vectors in
which the dominant selectable gene and unselectable gene of
interest are under the control of different promoters i.e.[,] the
use of a fusion gene encoding a chimeric protein ensures that
the expression of both the selected and unselected constituents
occurs in the selected cells.
Borrelli et al. and Moolten et al. each disclose that the
expression of negative selectable markers, particularly the
HSV1 thymidine kinase gene (HSV1-TK) within eukaryotic cells
(which are naturally TK+), is useful for the selective elimination
of particular cell types within a living organism. Moolten et al.
further disclose the use of the neomycin phosphotransferase
gene (NeoR) as a dominant selectable marker to select for cells
expressing the HSV1-TK gene as well[] as vectors for the
introduction of the HSV1-TK gene into cells which comprise both
a dominant selectable marker (NeoR) and the negatively
selectable gene (HSV1-TK) each under the control of a different
promoter. Cells expressing the HSV1-TK gene are selected for
by growing the transformed cells in the presence of neomycin.
Therefore, as positive selection for cells which express the
HSV1-TK gene is possible only in mutant TK- cells (whereas
both Borrelli et al. and Moolten et al. teach that one would
desire to produce cells which are naturally TK+ expressing this
gene), it would have been obvious to one of ordinary skill in the
art to construct a vector comprising a chimeric gene fusion
between the HSV1-TK gene and a dominant selectable marker
(such as NeoR) in order to be able to select for cells expressing
this useful gene within any cell type. One of ordinary skill in the
art would have been motivated to fuse the HSV1-TK gene to the
dominant selectable marker instead of using a vector similar to
that of Moolten et al. by the advantages of such a strategy
taught by Germann et al. It would have been further obvious to
transduce this vector into eukaryotic cells and to grow these
cells under the selection pressure of the dominant selectable
Page: Previous 1 2 3 4 5 6 7 8 9 10 Next
Last modified: November 3, 2007