(A) Schematic representation of the EUCOMM EUCE0171f01 gene trap introduced in between exons 20 and 21 of the murine Ubr5 gene. FRT, loxP and lox511 recombination sites, and their orientation, are indicated as triangles and flank the gene trap encoding for a splice acceptor site (SA), a LacZ and neomycin CDS (βgeo) and a poly-adenylation signal (pA). (B) Schematic representation of the effects of FLP and Cre-mediated recombination on the gene trap and UBR5 protein/domain expression–see text for details. (C-E) Brightfield images of control (C) Ubr5WT*/WT*, (D) Ubr5mt/+ and (E) Ubr5mt/mt E9.5 embryos. Scale bar = 1mm. Whole embryo qRT-PCR analysis of (F) Ubr5 at E9.5 and (G) Shh expression in the indicated genotypes at E9.5 or E8.5. Con = Ubr5+/+. n = ≥ 6, s.e.m indicated. Statistical analysis by Students t-test. ns = not significant.