Brain structures of a medaka mutant, el (eyeless), in which eye vesicles do not evaginate
Brain structures of a medaka mutant, el (eyeless), in which eye vesicles do not evaginate
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DOI：
10.1159/000047271
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发表时间：
2001-01-01
影响因子：
1.7
通讯作者：
Ozato, K
中科院分区：
文献类型：
--
作者：
Ishikawa, Y;Yoshimoto, M;Ozato, K
研究了一种突变硬骨鱼的眼发育和脑结构。青鳉（Oryzias latipes）的el（无眼）突变是隐性的，影响眼睛的形成;在最严重的情况下，它会导致眼睛的缺失。发育研究表明，正常的眼球在el突变胚胎中没有形成，但在前脑的壁上原位分化出了小的视杯状结构，没有外翻。无眼el纯合子鱼孵化正常，虽然他们没有响应视觉刺激的行为。这些鱼中有一小部分会长成成年鱼。在成年无眼el纯合子鱼，大脑表现出异常的几个细分。在端脑腹侧和视前区的表面上观察到一对小的异常突起。使用视紫红质单克隆抗体的免疫细胞化学显示，视蛋白阳性细胞存在于异常结构。Bodian染色显示异常结构附近存在视神经，尽管视神经纤维的数量非常少。视顶盖非常小，视层和纤维灰层厚度减少。这些行为和形态学观察表明，成年无眼el纯合子鱼是功能性失明，虽然小视网膜样结构的部分分化，并坚持在成鱼的大脑。此外，成年无眼el纯合子鱼不育，垂体和下丘脑的大小减少。因此，el突变不仅影响与视觉系统相关的大脑结构，还影响与生殖系统相关的大脑结构。
Eye development and brain structures of a mutant teleost fish were investigated. The el (eyeless) mutation in medaka (Oryzias latipes) is recessive and affects eye formation; in the most severe cases, it results in the absence of eyes. Developmental studies revealed that normal eyeballs are not formed in the el mutant embryos, but small optic cup-like structures differentiate in situ in the walls of the prosencephalon without evagination. The anophthalmic el homozygous fish hatched normally, although they did not respond behaviorally to visual stimuli. A small fraction of these fish grew to adulthood. In the adult anophthalmic el homozygous fish, the brain exhibited abnormalities in several subdivisions. A pair of small abnormal protrusions was observed on the surface of the ventral telencephalon and preoptic area. Immunocytochemistry using a rhodopsin monoclonal antibody showed that opsin-positive cells were present in the abnormal structures. Bodian staining showed that the optic nerves were present near the abnormal structures, although the number of optic nerve fibers was extremely small. The optic tectum was extremely small, and the thickness of the stratum opticum and stratum fibrosum et griseum superficiale was reduced. These behavioral and morphological observations suggest that the adult anophthalmic el homozygous fish are functionally blind, although small retina-like structures were partially differentiated and persisted in the adult fish brain. Moreover, the adult anophthalmic el homozygous fish were infertile, and the sizes of the hypophysis and the hypothalamus were reduced. Thus, the el mutation affects not only the brain structures that are related to the visual system but also those related to the reproductive system.