Pum1^{Gt(pU21)76Imeg}

The "promoter trap" gene trap vector pU21 contains 1.2 kb of intron 1 and part of exon 2, including the splice acceptor, from the mouse engrailed 2 gene (En2) followed by the Betageo beta-galactosidase/neomycin resistance fusion gene with the SV40 and mouse Pgk1 polyadenylation signals. Three stop codons occur in the exon sequence upstream of and in frame with the Betageo translation initiation codon. loxP and FRT sites used for 5' RACE analysis and for in vitro exchange of other sequences for Betageo are present. (J:109358)