Fig. 1

Homozygous pcsk9^{tpu-13/tpu-13} and pcsk9^{tpu-2,+15/tpu-2,+15} mutant zebrafish show reduced pcsk9 expression but normal morphology. A, A schematic representation of zebrafish pcsk9 (ENSDARG00000074185), and the gRNA target site for CRISPR/Cas9 mutagenesis in the third exon. B, The in vivo mutagenesis efficiency was estimated in the gRNA and Cas9 protein injected F0-generation embryos and in the uninjected controls using a T7 endonuclease I (T7EI) assay and 2.5% agarose TAE gel electrophoresis. The uninjected controls: a 169-bp WT PCR product (lanes 8 and 9); the gRNA and Cas9-injected mutant embryos: three bands of 169 bp (WT), ~100 bp and ~70 bp (lanes 1-7). The mutagenesis efficiency was calculated as described previously.²⁷ C, A schematic representation of the indel mutations (−13 bp deletion, pcsk9^tpu-13 and −2 bp deletion, +15 bp insertion, pcsk9^tpu-2,+15), leading to truncated protein products of 173 and 159 amino acids (aa) respectively. Red boxes indicate altered amino acids caused by the frameshift. D, The expression of pcsk9 was determined in the brain of pcsk9^{tpu-13/tpu-13} (n = 5; 2 females, 3 males) and pcsk9^{tpu-2,+15/tpu-2,+15} zebrafish (n = 5; 2 females, 3 males) and in the WT siblings (n = 5 in both control groups; 2 females, 3 males) with qPCR. Gene expression levels were normalized to eef1a1l1 and a 2-tailed Mann-Whitney test was used for statistics. E, Anesthetized WT and homozygous pcsk9 mutant zebrafish were imaged using a Canon EOS 7D Mark II camera with an exposure time of 17 ms. Fish were kept submerged in water during image acquisition. Images in (B) and (E) were cropped to exclude empty background from the figure