Appeal No. 2000-0441 Page 2
Application No. 08/866,942
5. A cell-based method for screening for modulators of a targeted gene
expression, said method comprising steps:
(a) isolating a genetic knock-in primary cell from a transgenic mouse made by
homologous recombination of a targeted native allele with a transgene comprising a
sequence encoding a reporter flanked by flanking sequences which effect the
homologous recombination of said transgene with said native allele, wherein the
expression of said reporter is under the control of native gene expression regulatory
sequences of said native allele,
(b) determining a first reporter expression level in a first isolated cell wherein said
first isolated cell is, or is a progeny of said genetic knock-in cell;
(c) contacting a second isolated cell wherein said second isolated cell is, or is a
progeny of said genetic knock-in cell with a candidate agent under conditions whereby
but for the presence of said agent, said reporter is expressed at said first reporter
expression level;
(d) determining a second reporter expression level in said second isolated cell;
(e) comparing said first expression level with said second expression level,
wherein a difference between said first and second expression levels indicates that said
candidate agent modulates the targeted gene expression.
The references relied on by the examiner are:
Foulkes et al. (Foulkes) 5,665,543 Sep. 9, 1997
Wadsworth et al. (Wadsworth) 5,720,936 Feb. 24, 1998
Skoultchi et al. (Skoultchi) WO 91/06667 May 16, 1991
The issue presented for review is whether claims 1-3 and 5-14 are unpatentable
under 35 U.S.C. § 103 in view of Foulkes, Wadsworth and Skoultchi.
DISCUSSION
According to the examiner, Foulkes describes genetic knock-in cells derived from
established cells lines by homologous recombination of a targeted native allele with a
transgene encoding a reporter, wherein the expression of the reporter is under the
control of the native gene expression regulatory sequences. Paper No. 4. The cells
are used in a reporter assay to screen candidate compounds for the ability to modulate
expression of the targeted native allele.
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