casanova plays an early and essential role in endoderm formation in zebrafish
casanova plays an early and essential role in endoderm formation in zebrafish
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DOI：
10.1006/dbio.1999.9441
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发表时间：
1999-11-15
影响因子：
2.7
通讯作者：
Stainier, DYR
中科院分区：
文献类型：
--
作者：
Alexander, J;Rothenberg, M;Stainier, DYR
调节脊椎动物内胚层发育的细胞和分子机制最近才开始被探索。在这里，我们表明斑马鱼基因座 casanova 在这一过程中发挥着早期和重要的作用。 casanova 突变体缺乏肠管，并且不表达任何内胚层分化的分子标记。 casanova 突变体中，诸如 axis、gata5 和 fkd2 等基因的早期内胚层表达并未启动，表明内胚层从原肠胚形成开始就有缺陷。镶嵌分析表明 casanova 在内胚层祖细胞内自主发挥细胞功能。我们还报道了斑马鱼 Mixer 同源基因的分离，Mixer 是爪蟾早期内胚层形成的重要基因。 casanova不编码斑马鱼Mixer，并且mixer表达在casanova突变体中是正常的，表明casanova在mixer下游或平行于mixer起作用以促进内胚层形成。我们进一步发现，前驱细胞（一组特殊的非退化背侧中内胚层细胞）在 casanova 突变体中不形成。正如之前所提出的那样，对 casanova 突变体的研究并不支持先行细胞在背轴或尾部发育中的重要作用。此外，虽然在casanova突变体中正常产生不同群体的中胚层前体，但心脏、脉管系统、血液和肾脏的形态发生缺陷是明显的，这表明内胚层在这些器官的形态发生中可能发挥作用。 (C) 1999 年学术出版社。
The cellular and molecular mechanisms that regulate endoderm development in vertebrates have only recently begun to be explored. Here we show that the zebrafish locus casanova plays an early and essential role in this process. casanova mutants lack a gut tube and do not express any molecular markers of endoderm differentiation. The early endodermal expression of genes such as axial, gata5, and fkd2 does not initiate in casanova mutants, indicating that the endoderm is defective from the onset of gastrulation. Mosaic analysis demonstrates that casanova functions cell autonomously within the endodermal progenitors. We also report the isolation of a zebrafish homologue of Mixer, a gene important for early endoderm formation in Xenopus. casanova does not encode zebrafish Mixer, and mixer expression is normal in casanova mutants, indicating that casanova acts downstream of, or parallel to, mixer to promote endoderm formation. We further find that the forerunner cells, a specialized group of noninvoluting dorsal mesendodermal cells, do not form in casanova mutants. Studies of casanova mutants do not support an important role for the forerunner cells in either dorsal axis or tail development, as has been previously proposed. In addition, although different populations of mesodermal precursors are generated normally in casanova mutants, morphogenetic defects in the heart, vasculature, blood, and kidney are apparent, suggesting a possible role for the endoderm in morphogenesis of these organs. (C) 1999 Academic Press.