Wild-derived XY sex-reversal mutants in the medaka, Oryzias latipes
Wild-derived XY sex-reversal mutants in the medaka, Oryzias latipes
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DOI：
10.1534/genetics.106.058941
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发表时间：
2006-08-01
期刊：
影响因子：
3.3
通讯作者：
Sakaizumi, Mitsuru
中科院分区：
文献类型：
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作者：
Otake, Hiroyuki;Shinomiya, Ai;Sakaizumi, Mitsuru
青鳉（Oryzias latipes）具有 XX/XY 性别决定机制。 DMY 是 Winked DM 结构域基因，已通过定位克隆分离出作为该物种的性别决定基因。此前，我们通过检查野生青鳉的基因型性别，发现了来自11个地点的23只XY性别反转雌性。遗传分析显示，所有这些女性都有 Y 连锁基因突变。在这里，我们的目的是澄清这种性别逆转的原因。为了实现这一目标，我们筛选了 DMY 氨基酸编码序列中的突变，并使用光密度半定量 RT-PCR 检查了孵化后 0 天 (dah) 的 DMY 表达。我们发现突变体可以分为两类。一种在 DMY 的氨基酸编码序列中含有突变，而另一种在 0 dab 时 DMY 表达降低，尽管 DMY 编码序列是正常的。对于后者，组织学分析表明，在测试的突变体中具有最低 DMY 表达的 (YYwOur)-Y-wOur（Y-wOur，源自 Oura XY 雌性的 Y 染色体）个体预计在 0 dah 时发育为雌性。这些结果表明早期睾丸发育需要 DMY 表达高于阈值水平。 DMY 表达减少的突变体可能对于鉴定 DMY 调控元件很有价值。
The medaka, Oryzias latipes, has an XX/XY sex-determination mechanism. A Winked DM domain gene, DMY has been isolated by positional cloning as a sex-determining gene in this species. Previously, we found 23 XY sex-reversed females from 11 localities by examining the genotypic sex of wild-caught medaka. Genetic analyses revealed that all these females had Y-linked gene mutations. Here, we aimed to clarify the cause of this sex reversal. To achieve this, we screened for mutations in the amino acid coding sequence of DMY and examined DMY expression at 0 days after hatching (dah) using densitometric semiquantitative RT-PCR. We found that the mutants could be classified into two groups. One contained mutations in the amino acid coding sequence of DMY while the other had reduced DMY expression at 0 dab although the DMY coding sequence was normal. For the latter, histological analyses indicated that (YYwOur)-Y-wOur (Y-wOur, Y chromosome derived from an Oura XY female) individuals with the lowest DMY expression among the tested mutants were expected to develop into females at 0 dah. These results suggest that early testis development requires DMY expression above a threshold level. Mutants with reduced DMY expression may prove valuable for identifying DMY regulatory elements.