The present invention is directed generally to activating gene expression
or causing over-expression of a gene by recombination methods in situ.
The invention also is directed generally to methods for expressing an
endogenous gene in a cell at levels higher than those normally found in
the cell. In one embodiment of the invention, expression of an endogenous
gene is activated or increased following integration into the cell, by
non-homologous or illegitimate recombination, of a regulatory sequence
that activates expression of the gene. In another embodiment, the
expression of the endogenous gene may be further increased by
co-integration of one or more amplifiable markers, and selecting for
increased copies of the one or more amplifiable markers located on the
integrated vector. In another embodiment, the invention is directed to
activation of endogenous genes by non-targeted integration of specialized
activation vectors, which are provided by the invention, into the genome
of a host cell. The invention also provides methods for the
identification, activation, isolation, and/or expression of genes
undiscoverable by current methods since no target sequence is necessary
for integration. The invention also provides methods for isolation of
nucleic acid molecules (particularly cDNA molecules) encoding a variety
of proteins, including transmembrane proteins, and for isolation of cells
expressing such transmembrane proteins which may be heterologous
transmembrane proteins. The invention also is directed to isolated genes,
gene products, nucleic acid molecules, to compositions comprising such
genes, gene products and nucleic acid molecules, and to vectors and host
cells comprising such genes and nucleic acid molecules, that may be used
in a variety of therapeutic and diagnostic applications. Thus, by the
present invention, endogenous genes, including those associated with
human disease and development, may be activated and isolated without
prior knowledge of the sequence, structure, function, or expression
profile of the genes.
