Patent ID: 7005299

Claim:
A method of inserting a gene of interest into an endogenous gene in a mouse embryonic stem cell such that the gene of interest is expressed in said mouse embryonic stem cell, wherein said method comprises transforming the mouse embryonic stem cell with a gene trap vector comprising a heterologous gene coding sequence: 5′ X-A-P-B-Q-C-Y-3′ wherein: X and Y are substantially homologous with separate sequences of the endogenous gene, and are of sufficient length to undergo homologous recombination with the endogenous gene so as to insert the A-P-B-Q-C elements into the host cell's genome; P is an internal ribosome entry site (IRES); Q is the gene of interest; A, B, and C are each independently at least one of a linker sequence and a covalent bond; a polyadenylation site is located 3′ (downstream) of Q; a splice acceptor site is located 5′ (upstream) of P; and wherein the heterologous gene coding sequence lacks a promoter element.