Fig. 5

A) Histogram showing the developmental stage attained by embryos at 24 h after fertilization when incubated in various concentrations of NaN3 from 6 hpf. Developmental stage is given as equivalent to the developmental age in hpf of embryos developing under normoxia at 28.5 °C. B) Nucleotide sequence alignment of the 3′ end of exon 5 in human PSEN2 and its orthologues. Red boxes enclose sequences aligned with the HMGA1a-binding sites in human PSEN2. C) RT-PCR on cDNA from zebrafish embryos amplifying a region spanning psen2 exons cognate to human PSEN2 exons 3 to 7 under hypoxic conditions and predicted PS2V-like splice product size. N.C. is a negative control (no DNA template in the PCR). No PCR product is observed at the 568 bp position predicted if the zebrafish exon cognate with human PSEN2 exon 5 was to be excluded.