Nakajima Keisuke, Shimamura Masaki, Furuno Nobuaki
Division of Embryology, Amphibian Research Center, Hiroshima University, Higashihiroshima, Japan.
Graduate School of Integrated Sciences for Life, Hiroshima University, Higashihiroshima, Japan.
Dev Dyn. 2021 Oct;250(10):1420-1431. doi: 10.1002/dvdy.334. Epub 2021 Apr 14.
Amphibians possess three kinds of dermal chromatophore: melanophores, iridophores, and xanthophores. Knockout Xenopus tropicalis that lack the pigmentation of melanophores and iridophores have been reported. The identification of the causal genes for xanthophore pigmentation or differentiation could lead to the creation of a see-through frog without three chromatophores. The genes causing xanthophore differentiation mutants are slc2a11b and slc2a15b in Japanese medaka (Oryzias latipes).
To obtain a heritable line of X tropicalis mutants without yellow pigment, we generated slc2a7 and slc2a15a knockout animals because they have the greatest similarity to the O latipes slc2a11b and slc2a15b genes. The slc2a7 knockout frog had a bluish skin and there were no visible yellow pigments in stereo microscope and skin section observations. Furthermore, no pterinosomes, which are characteristic of xanthophores, were observed via transmission electron microscopy in the skin of knockout animals.
We report the successful generation of a heritable no-yellow-pigment X tropicalis mutant after knock out of the slc2a7 gene. This finding will enable the creation of a see-through frog with no chromatophores.
两栖动物拥有三种真皮色素细胞：黑素细胞、虹彩细胞和黄色素细胞。已报道了缺乏黑素细胞和虹彩细胞色素沉着的热带爪蟾基因敲除品系。鉴定黄色素细胞色素沉着或分化的致病基因可能会培育出一种没有三种色素细胞的透明青蛙。在日本青鳉（Oryzias latipes）中，导致黄色素细胞分化突变体的基因是slc2a11b和slc2a15b。
为了获得无黄色素的热带爪蟾突变体的可遗传品系，我们培育了slc2a7和slc2a15a基因敲除动物，因为它们与青鳉的slc2a11b和slc2a15b基因具有最大的相似性。slc2a7基因敲除的青蛙皮肤呈蓝色，在立体显微镜和皮肤切片观察中未发现可见的黄色素。此外，在基因敲除动物的皮肤中，通过透射电子显微镜未观察到作为黄色素细胞特征的蝶酸体。
我们报道了在敲除slc2a7基因后成功培育出一种可遗传的无黄色素热带爪蟾突变体。这一发现将有助于培育出一种没有色素细胞的透明青蛙。
