REGULATION OF ANTEROPOSTERIOR PATTERNING IN EARLY FROG DEVELOPMENT

POU转录因子已被证明是重要的， 在发育过程中调节细胞命运的决定。 我们重点 了解POU基因XlPOU 2在早期神经细胞中的功能， 发展 该基因首先在Spemann的组织者中表达， 原肠胚形成的开始，使其成为最早的神经特异性 转录因子检测。 其时空格局 表达表明，它可能是调节神经诱导 过程 为了测试这种可能性，我们错误地表达了XlPOU 2， 将合成的XlPOU 2 mRNA注射到32-细胞的特定卵裂球中， 阶段胚胎。由于这种扰动，我们观察到一个开关 在表皮谱系向神经元表型的细胞命运中， 在完整的胚胎中，在体外，在未定型的外胚层中。 这些 实验表明，XlPOU 2作为前神经基因， 神经发生，并参与最初的决定外胚层细胞 在成为表皮细胞或神经细胞的过程中所必须的。 我们还 在斑马鱼中发现了几个新的POU基因， 表征脑-1相关基因Brn-1 r。 这个基因是72% 在氨基酸水平上与小鼠Brn-1同源。 与Brn-1不同， Brn-1 r的表达仅限于发育中的神经系统， 母亲的成绩单 在原肠胚形成过程中，Br-1 r表达于 胚的背侧部分，在内卷中胚层。 在后期阶段， Br-1 r的表达在神经系统中是突出的。 功能研究 正在进行中，以确定该基因是否参与了早期 在胚胎中形成图案。

POU transcription factors have been shown to be important in the regulation of cell fate decisions during development. We have focused on understanding the function of one POU gene, XlPOU 2, in early neural development. This gene is first expressed in Spemann's organizer at the beginning of gastrulation, making it one of the earliest neural-specific transcription factors detected. Its temporal and spatial pattern of expression suggests that it may be regulatory in the neural inductive process. To test this possibility, we have misexpressed XlPOU 2 by injecting synthetic XlPOU 2 mRNA into specific blastomeres of the 32-cell stage embryo. As a result of this perturbation we have observed a switch in cell fate of the epidermal lineage towards a neuronal phenotype both in intact embryos, and in vitro, in uncommitted ectoderm. These experiments suggest that XlPOU 2 has a role as a proneural gene in neurogenesis, and is involved in the initial decision ectodermal cells must make in becoming either epidermal or neuronal. We have also identified several novel POU genes in zebrafish, and have begun characterizing a Brain-1 related gene, Brn-1r. This gene is 72% homologous with mouse Brn-1 at the amino acid level. Unlike Brn-1, whose expression is restricted to the developing nervous system, Brn-1r is a maternal transcript. During gastrulation, Br-1r is expressed in the dorsal portion of the embryo, in involuting mesoderm. At later stages, Br-1r expression is prominent in the nervous system. Functional studies are underway to determine whether this gene is involved in early patterning in the embryo.