Fig. 2

Generation of dyrk1aa KO zebrafish and microcephaly phenotype analysis. a Schematic representation of the genomic structure of dyrk1aa and a 7 bp deletion generated by gene targeting with TALEN. b Predicted structures of WT and dyrk1aa KO mutant proteins in zebrafish. The 7 bp deletion resulted in a frame-shift mutation and premature termination at the kinase domain. c, d Similar brain size in WT (c) and KO fish (d) is seen at the 2-week-old stage. Fluorescent live neurons are visible in the genetic background of HuC:eGFP transgenic zebrafish. Anterior to the left, dorsal view. Scale bars 0.2 mm. e – j Sections of a 3-week-old zebrafish head region were immuno-stained with an antibody against activated caspase-3. Coronal sections at the level of the eye: bright-field image (e, h) and fluorescent image (f, g, i, and j). g, j Magnification of inset in (f, i). Arrows indicate caspase-3 positive cells in the brain. Scale bars 0.2 mm. k The number of caspase-3 positive cells is increased in the brain of KO fish. Five animals for each WT and KO fish were used for the analysis. Data are presented as mean ± SEM. * p < 0.05 by Student’s t test. l, m Pictures of adult WT and KO zebrafish. dyrk1aa KO zebrafish were normal in body length and overall morphology except for a reduction of brain size. Arrowheads indicate the position of the brain in the head region. Scale bars 5 mm. n, o Photograph of dissected brains from WT and KO zebrafish, showing microcephaly phenotype in KO zebrafish. Anterior olfactory bulbs were positioned at the left, ventral view. Scale bars 0.4 mm. p, q Confirmation of microcephaly phenotype in KO zebrafish by histological examination. Dashed line in n and o indicates the relative section position used in p and q. Brain sections were stained with H&E. KO zebrafish brain had wider ventricle space than WT zebrafish. Arrows point to TeV. Scale bars 0.4 mm