TABLE 2.
Comparison of wild-type and Cpr−/− embryos at 9.5 dpc from dams with altered RA supplya
| Genotype | Treatment (mg/kg) | Axial rotation | Pairs of somites | Branchial arches | Heart formation | Neural tube | Presence of limb buds | No. of examined embryos |
|---|---|---|---|---|---|---|---|---|
| Cpr+/+/Cpr+/− | None | Yes | 18-26 | 3 | Asymmetric looped | Closed | Yes | >300 |
| RA (5) | Yes | 18-26 | 2 or 3 | Looped, enlarged | Closed | Yes | 28 | |
| RA (7.5) | Yes | 16-21 | 0 or 1 | Asymmetric enlarged | Open | 0-2 forelimb buds | 27 | |
| VAD | Yes | 18-26 | 3 | Asymmetric looped | Closed | Yes | 42 | |
| Cpr−/− | None (P1) | Yes | 12-16 | 0 | Symmetric, enlarged | Open | No | >60 |
| None (P2) | No | 8-12 | 0 | Symmetric enlarged | Open | No | >140 | |
| RA (5) | No | <10 | 0 | Symmetric enlarged | Open | No | 3 | |
| RA (7.5) | 3 (resorptions) | |||||||
| VAD | Yes | 16-19 | 0 | Asymmetric | Open | No | 9 | |
| VAD | No | 16 | 0 | Asymmetric | Open | No | 1 |
a
Dams were gavaged with 7.5 or 5 mg of atRA/kg (n = 3 for each concentration) at 7.5 and 8.5 dpc or fed a normal diet or a VAD diet (n = 6), and embryos were harvested at 9.5 dpc. Note that no Cpr−/− embryos of mothers given a high dose of RA were identified, but three placentas found in the three litters contained resorbed material with a Cpr−/− genotype.