Airn^tm1Dpb

A 1.2 kb rabbit beta-globin fragment containing a polyadenylation cassette was inserted immediately downstream of the 3.7 kb imprint control element (ICE). The insertion was designed to truncate the RNA product to 4% of its length without disrupting the ICE. While the allele maintains its imprinted status and wild-type expression levels, the truncation results in a loss of gene silencing of the Igf2r/Slc22a2/Slc22a3 cluster on the paternal chromosome. An aberrant transcript was identified by RT-PCR analysis. This splice varient involved a splice donor 53 bp downstream of the transcription start site that joined a slice acceptor of transgenic beta-globin exon 3. (J:77594)