Ascl2^tm1.1Cle

A FRT-flanked neomycin cassette and a loxP site were placed in the non-coding exon 1 with an additional loxP site placed downstream of exon 2. The neomycin cassette was removed by crossing mice with a Flipase transgenic strain leaving the lone coding exon flanked by loxP sites. An Xho site is destroyed in the introduction of the FRT and loxP sites to exon 1. Restriction digests on cDNA from heterozygote placenta and intestinal extracts indicate that the gene is imprinted in placental tissue (the maternal allele is expressed) while there is no imprinting in intestinal stem cells (both alleles are expressed). (J:148715)