Imaging of Transgenic Cricket Embryos Reveals Cell Movements Consistent with a Syncytial Patterning Mechanism
Imaging of Transgenic Cricket Embryos Reveals Cell Movements Consistent with a Syncytial Patterning Mechanism
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DOI：
10.1016/j.cub.2010.07.044
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发表时间：
2010-09-28
期刊：
影响因子：
9.2
通讯作者：
Mito, Taro
中科院分区：
文献类型：
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作者：
Nakamura, Taro;Yoshizaki, Masato;Mito, Taro
昆虫胚胎发生的模式因物种而异，反映了对不同历史策略的适应[1，2]。在全变态昆虫中，包括模式系统，如果蝇和红粉甲虫，大部分胚盘产生胚胎，而半变态胚胎通常产生于胚盘的一小部分[3]。尽管半变态昆虫在进化研究中的重要性，但其早期发育动态的信息仍然有限。在这里，为了澄清母亲和差距基因产物的行为在图案化的胚胎的基础hemimetrometous昆虫，我们分析了动态分割过程中的转基因胚胎的中间胚昆虫物种，蟋蟀，蟋蟀bimaculatus。我们的数据的基础上实时成像的荧光标记的胚胎细胞和细胞核表明，细胞胚盘的位置规格可能会建立在合胞体，其中母系衍生的梯度可以从根本上起作用的方式是类似的果蝇，即在整个鸡蛋。然后，胚盘细胞动态地移动，保留它们的位置信息，以形成后部定位的生殖原基。此外，我们发现，前头部区域的蟋蟀胚胎是指定的正齿在细胞环境中早于颌和胸部区域。我们的研究结果意味着，在长胚昆虫早期分割的合胞体模式演变从一个动态的合胞体到细胞的模式，在本研究中发现，伴随着一个异时移位的差距基因的行动。
The mode of insect embryogenesis varies among species, reflecting adaptations to different lite history strategies [1, 2]. In holometabolous insects, which include the model systems, such as the fruit fly and the red flour beetle, a large proportion of the blastoderm produces an embryo, whereas hemimetabolous embryos generally arise from a small region of the blastoderm [3]. Despite their importance in evolutionary studies, information of early developmental dynamics of hemimetabolous insects remains limited. Here, to clarify how maternal and gap gene products act in patterning the embryo of basal hemimetabolous insects, we analyzed the dynamic segmentation process in transgenic embryos of an intermediate-germ insect species, the cricket, Gryllus bimaculatus. Our data based on live imaging of fluorescently labeled embryonic cells and nuclei suggest that the positional specification of the cellular blastoderm may be established in the syncytiurn, where maternally derived gradients could act fundamentally in a way that is similar to that of Drosophila, namely throughout the egg. Then, the blastoderm cells move dynamically, retaining their positional information to form the posteriorly localized germ anlage. Furthermore, we find that the anterior head region of the cricket embryo is specified by orthodenticle in a cellular environment earlier than the gnathal and thoracic regions. Our findings imply that the syncytial mode of the early segmentation in long-germ insects evolved from a dynamic syncytial-to-cellular mode found in the present study, accompanied by a heterochronic shift of gap gene action.