Expression patterns of a twist-related gene in embryos of the spider Achaearanea tepidariorum reveal divergent aspects of mesoderm development in the fly and spider
Expression patterns of a twist-related gene in embryos of the spider Achaearanea tepidariorum reveal divergent aspects of mesoderm development in the fly and spider
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DOI：
10.2108/zsj.22.177
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发表时间：
2005-02-01
影响因子：
0.9
通讯作者：
Oda, Hiroki
中科院分区：
文献类型：
--
作者：
Yamazaki, Kazunori;Akiyama-Oda, Yasuko;Oda, Hiroki
我们克隆了一个Achaearanea tepidariorum（Chelicerata，蛛形纲）基因相关的果蝇扭曲（twi），它编码一个基本的螺旋-环-螺旋转录因子所需的指定中胚层的命运在果蝇胚胎。克隆的蜘蛛基因被命名为At. twi（At.twi）。我们通过整体原位杂交检测其表达。当卵丘到达赤道时，在位于球形胚胎的极区和赤道区的细胞中首先检测到At.twi转录本。随着胚外区的扩大，更多的细胞表达At。twi成绩单。表达At. twi的细胞几乎均匀地分布在胚胎区域。在这些阶段，在表面上皮细胞层中发现一些At. twi表达细胞，但其他At. twi表达细胞位于离表面稍深的位置。当胚胎转化为胚带时，所有表达At. twi的细胞都位于外胚层表面之下，在那里它们变成同色异谱排列。虽然很少的表达中观察到的延长胚芽带的尾叶，新的条纹的At.twi表达出现在外胚层根据后方的增长。这些观察结果表明，表达At.twi的细胞最有可能是中胚层。我们认为At.twi可以作为分析蜘蛛胚胎中胚层发育的分子标记。此外，twi和At.twi的表达模式的比较揭示了在苍蝇和蜘蛛中胚层发育的不同方面。此外，我们克隆了与蜗牛相关的Achaearanea基因，这是果蝇中的另一个中胚层决定基因，并表明其表达仅限于外胚层，没有迹象表明在中胚层发育中的作用。
We cloned an Achaearanea tepidariorum (Chelicerata, Arachnida) gene related to Drosophila twist (twi), which encodes a basic helix-loop-helix transcription factor required to specify mesoderm fate in the Drosophila embryo. The cloned spider gene was designated At.twist (At.twi). We examined its expression by whole-mount in situ hybridization. At.twi transcripts were first detected in cells located at the polar and equatorial areas of the spherical embryo when the cumulus reached the equator. As the extra-embryonic area expanded, more cells expressed At. twi transcripts. The At.twi-expressing cells became distributed nearly uniformly in the embryonic area. At these stages, some At.twi-expressing cells were found in the surface epithelial cell layer, but other At.twi-expressing cells were at slightly deeper positions from the surface. When the embryo was transformed into a germ band, all At.twi-expressing cells were situated just beneath the surface ectoderm, where they became metamerically arranged. Although little expression was observed in the caudal lobe of the elongating germ band, new stripes of At.twi expression appeared beneath the ectoderm in accordance with the posterior growth. These observations suggested that the cells expressing At.twi were most likely mesoderm. We propose that At.twi can be used as a molecular marker for analyzing mesoderm development in the spider embryo. Moreover, comparison of the expression patterns of twi and At.twi revealed divergent aspects of mesoderm development in the fly and spider. In addition, we cloned an Achaearanea gene related to snail, which is another mesoderm-determining gene in Drosophila, and showed that its expression was restricted to the ectoderm with no indication for a role in mesoderm development.