The gene trap vector insertion site was mapped to nucleotide 12535 within intron 1 of the Dcp2 gene. Western analysis of several organs from 4-week-old wild-type (WT) and homozygous littermates revealed the mice containing a homozygous insertion of the gene trap vector were not completely devoid of Dcp2 expression and were instead phenotypically hypomorphic with reduced protein expression in the different tissues that Dcp2 can normally be detected.