Fig. 1

Hoxb1b^ua1006 and hoxb1a^sa1191 mutations.

(A) The hoxb1b^ua1006 mutation was generated via TALEN-mediated mutagenesis and contains a 13 bp insertion 63 bp downstream of the start codon. This mutation results in a truncated 43aa protein. (B) The hoxb1a^sa1191 mutation contains a G to A resulting in a truncation part way through the homeodomain at amino acid 269. To determine if the protein produced by the hoxb1b^ua1006 allele retains any function, 200 pg of wildtype hoxb1b RNA (D) and 200 pg of mutant hoxb1b RNA containing the ua1006 mutation (E) were over expressed. In situ hybridization for the 3’UTR of hoxb1a in uninjected controls (C,F) shows normal expression in rhombomere 4. Overexpression of wildtype hoxb1b RNA results in a homeotic transformation where a duplicated region hoxb1a expression is observed in r2 (66/88 embryos affected) (D). Overexpression of hoxb1b^ua1006 RNA fails to cause a homeotic transformation, indicating a lack of biological activity (0/82 embryos affected) (E). Similarly, to determine if the protein produced by the hoxb1a^sa1191 allele retains any function, 50 pg of wildtype hoxb1a RNA (G) and 50 pg of mutant hoxb1b RNA containing the sa1191 mutation (H) were over expressed. Overexpression of wildtype hoxb1a RNA results in a homeotic transformation where a duplicated region hoxb1a expression is observed in r2 (30/34 embryos affected) (G). Overexpression of hoxb1a^sa1191 RNA fails to cause a homeotic transformation, indicating a lack of biological activity (0/38 embryos affected)(H). All embryos are dorsal views, anterior to the left, 18hpf.