Table 1.
Phenotypes of embryos carrying combinations of Grhl3 loss of function and overexpressing alleles
| Spinal phenotype % (n) | |||||
|---|---|---|---|---|---|
| Genotype | No. embryos | Straight tail | TFDs | SB & TFDs | P |
| Grhl3ct/ct | 13 | 77 (10) | 15 (2) | 8 (1) | |
| Grhl3 ct/ct;TgGrhl3/0 | 8 | 100 (8) | 0 (0) | 0 (0) | |
| Grhl3 ct/ct;TgGrhl3/TgGrhl3 | 9 | 11 (1) | 11 (1) | 78 (7) | <0.001 |
| Grhl3ct/- | 10 | 20 (2) | 30 (3) | 50 (5) | |
| Grhl3 ct/-;TgGrhl3/0 | 10 | 100 (12) | 0 (0) | 0 (0) | |
| Grhl3 ct/-;TgGrhl3/TgGrhl3 | 10 | 30 (3) | 0 (0) | 70 (7) | <0.001 |
| Grhl3-/- | 11 | 0 (0) | 0 (0) | 100 (11) | |
| Grhl3 -/-;TgGrhl3/0 | 12 | 100 (12) | 0 (0) | 0 (0) | |
| Grhl3 -/-;TgGrhl3/TgGrhl3 | 8 | 62 (5) | 0 (0) | 38 (3) | <0.001 |
Offspring of Grhl3ct/-;TgGrhl3/0 intercrosses were assessed at E11.0–18.5 for the presence of NTDs and/or TFDs. NTDs did not arise among embryos heterozygous for the Grhl3 transgene irrespective of the endogenous genotype. Differences in the number (0, 1 or 2) of Grhl3 transgene copies was associated with significant variation in the distribution of spinal phenotypes among Grhl3ct/ct, Grhl3ct/- and Grhl3-/- embryos (P < 0.001; Chi-square).