The PrP-like protein Doppel gene in sheep and cattle: cDNA sequence and expression.

cDNAs encoding the ovine and bovine prion protein-like protein Doppel (Dpl) have been cloned. Sequencing revealed cDNAs of 2.85 and 3.31 kb from ovine and bovine testicular tissue, in accordance with observations of single transcripts of 3.2 and 3.6 kb on Northern blots. Sequence alignments showed a very high degree of identity between the sheep and cattle Dpl cDNAs, except for a 0.4-kb stretch in the bovine 3' untranslated region and the terminal 3' end of the sequences. The expression pattern of the Dpl gene (Prnd) in adult tissues from both species was compared by Northern blot and RT-PCR analyses. The Prnd gene was expressed strongly in testicular tissue, while low levels of expression were seen in other tissues. The open reading frame of the ovine and bovine sequences encodes a 178-amino acid protein with 95% sequence identity between the two species. Predicted structural features are in close agreement with previous reports for mouse, human, and rat Dpl.