vasa mRNA accumulates at the posterior pole during blastoderm formation in the flour beetle Tribolium castaneum
vasa mRNA accumulates at the posterior pole during blastoderm formation in the flour beetle Tribolium castaneum
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面粉甲虫 赤拟谷盗 胚盘形成过程中 vasa mRNA 在后极积聚
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发表时间：
2006
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通讯作者：
Reinhard Schröder
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作者：
Reinhard Schröder
胚胎发生过程中生殖细胞的正确规范是生命中确保下一代存在的基本步骤。尽管不同物种表现出不同的产生生殖细胞的细胞模式，vasa基因的产物被证明是后生动物原始生殖细胞的可靠标记[Extavour and Akam (2003) 130:5869–5884；拉兹（2000）1：1017]。在这里，我报告了从赤拟谷盗中分离出 vasa 直向同源物，命名为 Tc-vasa，并描述了它的序列、基因组结构及其在早期胚胎发生过程中的表达模式。与果蝇的 vasa 信使 RNA (mRNA) 广泛分布在卵中不同，Tc-vasa mRNA 在胚盘形成过程中逐渐在卵后极积累。原肠胚形成前不久，Tc-vasa mRNA 标记后极的一组囊胚内细胞。在胚芽中，血管阳性细胞的球状群粘附在胚胎后端的生长区。这些vasa阳性细胞可能代表在性腺形成之前在Tribolium中尚未描述的原始生殖细胞。在细菌生长开始时，一小群血管阳性细胞开始沿着生长区的背侧迁移。 vasa 转录在进一步的种带延伸过程中停止。与果蝇相反，在分割完成后，在性腺原基内的生殖细胞中无法检测到 Tc-vasa 转录本。
The correct specification of germ cells during embryogenesis is a fundamental step in life that ensures the existence of the next generation. Although different species display various cellular modes of generating germ cells, the product of the vasa gene proves to be a reliable marker of primordial germ cells in metazoans [Extavour and Akam (2003) 130:5869–5884; Raz (2000) 1:1017]. Here, I report the isolation of the vasa ortholog from the red flour beetle Tribolium castaneum, named Tc-vasa, and describe its sequence, its genomic organisation and its expression pattern during early embryogenesis. Unlike in Drosophila where vasa messenger RNA (mRNA) is ubiquitously distributed in the egg, Tc-vasa mRNA gradually accumulates at the posterior egg pole during blastoderm formation. Shortly before gastrulation, Tc-vasa mRNA marks a group of intra-blastodermal cells at the posterior pole. In the germ rudiment, a ball-like group of vasa-positive cells adheres to the growth zone at the posterior end of the embryo. These vasa-positive cells likely represent the primordial germ cells that have not been described in Tribolium prior to gonad formation. At the beginning of germ growth, a small band of vasa-positive cells starts to migrate along the dorsal side of the growth zone. vasa transcription ceases during further germ band extension. In contrast to Drosophila, Tc-vasa transcripts cannot be detected in the germ cells within the gonadal anlage after segmentation is completed.