Zebrafish wnt8 and wnt8b share a common activity but are involved in distinct developmental pathways.
Zebrafish wnt8 and wnt8b share a common activity but are involved in distinct developmental pathways.
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发表时间：
1995-06
期刊：
影响因子：
4.6
通讯作者：
G. Kelly;P. Greenstein;D. Erezyilmaz;R. Moon
中科院分区：
文献类型：
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作者：
G. Kelly;P. Greenstein;D. Erezyilmaz;R. Moon
脊椎动物的身体结构依赖于许多信号分子，包括Wnt家族的成员。我们已经确定了两个与Xwnt-8B和Xwnt-8相关的斑马鱼wnt8类似物。RT-PCR分析表明，wnt8在母体中表达，在整个胚胎发育过程中都能检测到转录本，而wnt8b转录本在原肠胚后期首次被检测到。50%的wnt8转录本在空间上局限于胚皮边缘的细胞，覆盖在轴向下胚中表达gsc的细胞上。在原肠胚后期，在背中线边缘细胞中不再检测到wnt8，通过中期分割，在假定的尾芽中发现了转录本。相比之下，wnt8b的表达在空间上仅限于前瞻性神经上皮，然后是神经特异性结构。这两种基因的过表达会导致两种主要的表型：放射状胚胎和具有前侧缺陷的胚胎。在这些表型之前，gsc和ntl转录本的空间表达模式发生了显著变化，这让人想起了Xwnt-8在非洲爪蟾中的活动，并且与wnt8在中胚层的规范或模式中的作用一致。
The specification of the vertebrate body plan is dependent on numerous signaling molecules, including members of the Wnt family. We have identified two zebrafish wnt8 paralogs related to Xwnt-8B and Xwnt-8, respectively. A RT-PCR assay demonstrated that wnt8 is expressed maternally, with transcripts detected throughout embryogenesis, whereas wnt8b transcripts were first detected during late gastrulation. The wnt8 transcripts at 50% epiboly are spatially restricted to those cells at the blastoderm margin, overlying gsc-expressing cells in the axial hypoblast. During late gastrulation, wnt8 was no longer detected in the marginal cells at the dorsal midline and by mid-segmentation, transcripts were found in the presumptive tail bud. In contrast, wnt8b expression is spatially restricted to prospective neuroepithelium, and later to neural-specific structures. Overexpression of both wnts results in two major phenotypes: radialized embryos and embryos with anterior defects. These phenotypes were preceded by significant changes in the spatial expression patterns of gsc and ntl transcripts, reminiscent of activities of Xwnt-8 in Xenopus, and consistent with a role for wnt8 in the specification or patterning of mesoderm.