(b) Protein extracts from wild-type (Ambra1+/+) and homozygous (Ambra1gt/gt) embryos for the Ambra1 gene-trap mutation at developmental day 14.5 were analysed by western blotting using anti-Ulk1 or anti-Hsp90 (loading control) antibodies. Quantification is shown on the right. n = 6 extracts prepared from independent experiments. Data are presented as means±s.d. and significance is P = 0.037. 