Table 1.

Summary of combinatorial cyp26 knock-down experiments and their outcomes.

treatment	summary of phenotype
	cyp26a1+	cyp26a1-/-
5ng control MO	none	very mild (expanded r4)
2.5 ng cyp26b1 MO1 + 2.5 ng control MO	none	very mild (expanded r4)
2.5 ng cyp26c1 MO1 + 2.5 ng control MO	none	medium (up to cerebellum)
2.5 ng cyp26b1 MO + 2.5 ng cyp26c1 MO	none	severe (up to cerebellum)
5 nM RA	none	severe (throughout brain)
10 μM DEAB + 5 nM RA	none	severe (throughout brain)

Morpholino sequences:
cyp26b1 MO1 (ATG)	5’-CTCGAAGAGCATGGCTGTGAACGTC-3’
cyp26b1 MO2 (exon 2-intron 2 splice)	5’- ATTGACCTTACCTTCCTCCTTTTGC-3’
cyp26c1 MO1 (exon 3-intron 3 splice)	5’-AAACTCGGTTATCCTCACCTTGCGC-3’
cyp26c1 MO2 (intron 1-exon 2 splice)	5′-GGAACCCTGTCACAACATAACAGAG-3′
control (deadend MO)	5′-GCTGGGCATCCATGTCTCCGACCAT-3′