Patent ID: 7662941

Claim:
A composition comprising a bacterial artificial chromosome (BAC), wherein said BAC comprises a) a reporter gene having a 5′ end and a 3′ end, b) a first Nanog gene regulatory sequence operably linked to said 5′ end of said reporter gene, wherein said first Nanog gene regulatory sequence is produced by amplification of a mouse DNA sequence using a first PCR forward primer (SEQ ID NO:3) and a first PCR reverse primer (SEQ ID NO:4) in a first polymerase chain reaction, and c) a second Nanog gene regulatory sequence operably linked to said 3′ end of said reporter gene, wherein said second Nanog gene regulatory sequence is produced by amplification of a mouse DNA sequence using a second PCR forward primer (SEQ ID NO:5) and a second PCR reverse primer (SEQ ID NO:6) in a second polymerase chain reaction, wherein the level of expression of said reporter gene is lower in a differentiated mouse embryonic stem cell comprising said BAC compared to the level of expression of said reporter gene in an undifferentiated mouse embryonic stem cell comprising said BAC.