Iida Atsuo, Takamatsu Naofumi, Hori Hiroshi, Wakamatsu Yuko, Shimada Atsuko, Shima Akihiro, Koga Akihiko
Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Japan.
Pigment Cell Res. 2005 Oct;18(5):382-4. doi: 10.1111/j.1600-0749.2005.00247.x.
We have previously identified three naturally occurring mutations in the medaka fish tyrosinase gene caused by transposable element insertions. Tyr-i(b) is one of these, containing the Tol2 element in the promoter region. Its homozygous carriers exhibit a weak oculocutaneous albino phenotype. We report here spontaneous reversion of the albino phenotype to the wild-type pigmentation, associated with excision of the Tol2 element. The newly arising mutant gene is inherited in the Mendelian fashion. Thus, oculocutaneous albinism is not strictly irreversible, at least in this organism and the results also indicate that the insertion of the Tol2 element is the main, and possibly the only, cause of the i(b) albinism. Importantly our data also suggest that medaka fish possess an active transposase.
我们之前已经鉴定出由转座元件插入导致的青鳉鱼酪氨酸酶基因的三种自然发生的突变。Tyr-i(b) 就是其中之一，其启动子区域含有 Tol2 元件。其纯合携带者表现出轻度眼皮肤白化病表型。我们在此报告白化病表型自发恢复为野生型色素沉着，这与 Tol2 元件的切除有关。新出现的突变基因以孟德尔方式遗传。因此，眼皮肤白化病并非严格不可逆，至少在这种生物中是这样，并且结果还表明 Tol2 元件的插入是 i(b) 白化病的主要原因，甚至可能是唯一原因。重要的是，我们的数据还表明青鳉鱼拥有一种活跃的转座酶。
