Figure S1.

(A) CRISPR/Cas9 was used to create a 2-bp deletion in exon 2 of exosc8. This would cause a frameshift and result in a premature stop codon and significantly truncated protein or degradation of the mRNA via nonsense-mediated decay. (B) CRISPR/Cas9 was used to create an 11-bp deletion in exon 3 of exosc9. This would cause a frameshift and result in a premature stop codon and significantly truncated protein or mRNA degradation via nonsense-mediated decay. (C) The 2-bp deletion generated in exosc8 could be identified by PCR of genomic DNA, followed by a restriction digest using TseI and then gel electrophoresis to genotype zebrafish. The wild-type allele remains uncut, whereas a new TseI restriction site appears in the mutant allele (GCAGC, TseI site is GCWGC). (D) The 11-bp deletion generated in exosc9 could be identified by PCR of genomic DNA, followed by gel electrophoresis to genotype zebrafish. The 11-bp difference between the wild -type band and the shorter mutant band can be visualised on a high percentage agarose gel. (E) RT-PCR for exosc9 in wild-type and exosc9 homozygous mutant fish reveals a reduction of exosc9 transcript in the mutants. The RT-PCR is not quantitative but shows a reduced band intensity in the exosc9 fish.