Figure 4. Rescue of Igf2r^+m/HUpmaternal transmission growth phenotype by loss of function of Igf2 and gain of function of Igf2r.

(A) Maternal transmission to generate Igf2r^HUm/+p was combined with paternal transmission of the paternal null allele of Igf2^+m/−p to generate combined heterozygotes (Igf2r^HUm/+p, Igf2^+m/−p). Post-natal growth curves show that maternal transmission of the maternal allele did not alter growth rates when lethality was rescued by loss of Igf2 (Table 1). (B) Lethality of Igf2r^HUm/+p was rescued by paternal expression of Igf2r murine allele (R2Δ^+m/−p, see Table 1) and subsequent post-natal growth kinetics appeared similar.