Figure 4

The effects of maternal transmission of Igf2r^I1565A/+p on survival and postnatal growth growth. (a) Kaplan-Meier survival plots following maternal transmission of Igf2r^I1565A/+p resulting in heterozygote and homozygote PCR confirmed genotypes. Comparison of wild-type and heterozygote Igf2r^I1565A/+p, (p = 0.0043), and comparison of wild-type and homozygote Igf2r^{I1565A/I1565A}, (p = 0.0003 Log-rank, Mantel-Cox test). (b) Postnatal weights of surviving littermates (±S.D.) from birth to 21 days. Comparison of wild-type and heterozygote Igf2r^I1565A/+p growth was non-significantly different (p = 0.68). (c) Gross appearances of neonatal and adult (6–8 weeks) wild-type and heterozygote Igf2r^I1565A/+p littermates; female uteri (upper panel), new born pups (lower left panel) and male genitalia (lower right panel). (d,e) Comparison of neonatal body weight (d) and heart weight (e) for wild-type, Igf2r^I1565A/+p and Igf2r^{I1565A/I1565A} genotypes. Note that the surviving homozygote Igf2r^{I1565A/I1565A} were not significantly different from wild-type (NS-body weight p = 0.2470, NS-heart weight p = 0.1583), whereas the heterozygotes Igf2r^I1565A/+p genotyped pups were significantly heavier (***body weight p < 0.0001, *heart weight p = 0.008). Horizontal line = mean, box plots 95% ± whiskers maximum and minimum. Unpaired two-way t-test. (f) H & E stained formalin fixed and paraffin embedded sections through lungs (upper panel) and hearts (lower panel) for wild-type and Igf2r^I1565A/+p pups that died at birth. Note the alveolar and bronchiole haemorrhage (arrow, upper panel) and the thickened and trabeculated ventricular wall muscle (arrow, lower panel) in Igf2r^I1565A/+p.