Transgenic line with gal4 insertion useful to study morphogenesis of craniofacial perichondrium, vascular endothelium-associated cells, floor plate, and dorsal midline radial glia during zebrafish development

Authors

  • Sohei Nakayama,

    1. Graduate School of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori, Akou-gun, Hyogo 678-1297
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  • Takanori Ikenaga,

    1. Graduate School of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori, Akou-gun, Hyogo 678-1297
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  • Koichi Kawakami,

    1. Division of Molecular and Developmental Biology, National Institute of Genetics, Department of Genetics, The Graduate University for Advanced Studies (SOKENDAI), 1111 Yata, Mishima, Shizuoka 411-8540, Japan
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  • Fumihito Ono,

    1. Laboratory of Molecular Physiology, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA
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  • Kohei Hatta

    Corresponding author
    1. Graduate School of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori, Akou-gun, Hyogo 678-1297
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Author to whom all correspondence should be addressed.
Email: khatta@sci.u-hyogo.ac.jp

Abstract

Zebrafish is a good model for studying vertebrate development because of the availability of powerful genetic tools. We are interested in the study of the craniofacial skeletal structure of the zebrafish. For this purpose, we performed a gene trap screen and identified a Gal4 gene trap line, SAGFF(LF)134A. We then analyzed the expression pattern of SAGFF(LF)134A;Tg(UAS:GFP) and found that green fluorescent protein (GFP) was expressed not only in craniofacial skeletal elements but also in the vascular system, as well as in the nervous system. In craniofacial skeletal elements, strong GFP expression was detected not only in chondrocytes but also in the perichondrium. In the vascular system, GFP was expressed in endothelium-associated cells. In the spinal cord, strong GFP expression was found in the floor plate, and later in the dorsal radial glia located on the midline. Taking advantage of this transgenic line, which drives Gal4 expression in specific tissues, we crossed SAGFF(LF)134A with several UAS reporter lines. In particular, time-lapse imaging of photoconverted floor-plate cells of SAGFF(LF)134A;Tg(UAS:KikGR) revealed that the floor-plate cells changed their shape within 36 h from cuboidal/trapezoidal to wine glass shaped. Moreover, we identified a novel mode of association between axons and glia. The putative paths for the commissural axons, including pax8-positive CoBL interneurons, were identified as small openings in the basal endfoot of each floor plate. Our results indicate that the transgenic line would be useful for studying the morphogenesis of less-well-characterized tissues of interest, including the perichondrium, dorsal midline radial glia, late-stage floor plate, and vascular endothelium-associated cells.

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