Fig. 1

Early development of the choriocapillaris in zebrafish. A: Time lapse confocal micrographs of the developing choriocapillaris (vessels shown in green) of the outer eye field in Fli1a:EGFP embryos at 18?23?h post fertilization (hpf, top row) and 24?120 hpf (lower row). Boxed regions are shown in magnified images below. Yellow arrows point to the indicated vessel structures, yellow arrowheads points to the avascular area or interstitial foci while white arrowheads points to endothelial cells or vessels. The dotted line indicates the eye field. Size bars indicates 50??m in each image. CrDI: Cranial division of internal carotid artery, HA: Hyaloid artery, OA: Optic artery, PMBC: Primordial midbrain channel. DRV: Dorsal radial vessel. NRV: Nasal radial vessel. B: Quantifications of the number of the endothelial cells in the experiment shown in A. n = 10?15 embryos, **: p < 0.01 ***: p < 0.001. C: Quantification of the number of interstitial foci in the experiment shown in A. n = 10?15 embryos, ***:p < 0.001. D: Quantification of the vascular density of choriocapillaris in the experiment shown in A. n = 10?15 embryos, ***:p < 0.001. E: Imaris 3D rendering images of the choriocapillaris showing the lumen of CCs of complete intussusceptive pillars (red arrow) and incomplete pillars (white arrows) from 72, 96 and 120 hpf. Size bar indicates 10??m. hpf: hours post fertilization. F: Scheme illustrating the development of choriocapillaris from 24 hpf to 120 hpf. Development of the choriocapillaris begins with the invasion of the endothelial cells via the PMBC and CrDi at 18?24 hpf. At 36 hpf the endothelial cells forms aggregates (blood islands) interconnected by thin processes (EC-EC connections), leading to formation of a primitive, non-lumenized vasculature at 48 hpf. The choriocapillaris become perfused at 72 hpf but remains actively expanding until maturation occurs at 120 hpf.