Drapc1 expression during mouse embryonic development

We identified the mouse homolog of human DRAPC1 (APCDD1) gene, shown to be a target of Wnt/beta-catenin signaling pathway in cancer cell lines. Analysis of its spatiotemporal expression in mouse embryos from E7.5 to E14 showed that Drapc1 is expressed during development of the extraembryonic structures, nervous system, vascular system and inner ear. In addition, Drapc1 is expressed in the mesenchyme of several developing organs at sites of epithelio-mesenchymal interactions. Drapc1 expression was also found in the hair follicles of the adult mouse skin. Similarity of Drapc1 expression pattern to location of active beta-catenin in developing mouse embryo further suggests that mouse Drapc1 is a novel in vivo target gene of Wnt/beta-catenin signaling pathway.     

Expression of two novel mouse Iroquois homeobox genes during neurogenesis

Members of the Drosophila Iroquois homeobox gene family are implicated in the development of peripheral nervous system and the regionalization of wing and eye imaginal discs. Recent studies suggest that Xenopus Iroquois homeobox (Irx) genes are also involved in neurogenesis. Three mouse Irx genes, Irx1, Irx2 and Irx3, have been previously identified and are expressed with distinct spatio-temporal patterns during neurogenesis. We report here the cloning and expression analysis of two novel mouse Irx genes, Irx5 and Irx6. Although Irx5 and Irx6 proteins are structurally more related to one another, we find that Irx5 displays a developmental expression pattern strikingly similar to that of Irx3, whereas Irx6 expression resembles that of Irx1. Consistent with the notion that Mash1 is a putative target gene of the Irx proteins, all four Irx genes display an overlapping expression pattern with Mash1 in the developing CNS. In contrast, the Irx genes and Mash1 are expressed in complementary domains in the developing eye and olfactory epithelium.     

cfm is a novel gene uniquely expressed in developing forebrain and midbrain, but its null mutant exhibits no obvious phenotype

A novel gene, cfm, that is expressed uniquely during early forebrain and midbrain development was isolated, and its null mutant was generated. cfm does not have any known functional domains, but is conserved in human, chick, Xenopus and zebrafish; a site of phosphorylation by MAP kinase exists in one of the domains conserved among them. Its expression was initially found at the 5-somite stage in the future midbrain and caudal forebrain region. The expression in mesencephalon subsequently decreased, was found in a stripe in the mid mesencephalon at E9.0. The expression in diencephalon was restricted to the dorsal thalamic region by E9.5 and to epiphysis at E12.5. In mouse a cognate, cfm2, exists that is expressed uniquely in the somite just formed and the presomite to be segmented, but not in forebrain or midbrain during early development. However, the cfm null mutant was live-born without any apparent defects.     

Xenopus marginal coil (Xmc), a novel FGF inducible cytosolic coiled-coil protein regulating gastrulation movements

Gastrulation in vertebrates is a highly dynamic process driven by convergent extension movements of internal mesodermal cells, under the regulatory activity of the Spemann-Mangold or gastrula organizer. In a large-scale screen for genes expressed in the organizer, we have isolated a novel gene, termed Xmc, an acronym for Xenopus marginal coil. Xmc encodes a protein containing two widely spaced evolutionarily non-conserved coiled coils. Xmc protein is found in vesicular aggregates in the cytoplasm and associated with the inner plasma membrane. We show that Xmc is expressed in a dynamic fashion around the blastoporal circumference, in mesodermal cells undergoing morphogenetic movements, in a pattern similar to FGF target genes. Likewise, Xmc expression can be induced by ectopic XeFGF signaling and the early mesodermal expression is dependent on FGF receptor-mediated signaling. Morpholino-mediated translational 'knock-down' of Xmc results in embryos that display a reduced elongation of the antero-posterior axis and in a pronounced inhibition of morphogenetic movements in embryos and dorsal marginal zone explants. Xmc loss-of-function does not interfere with mesoderm induction or maintenance per se. Our results suggest that Xmc is a novel FGF target gene that is required for morphogenetic movements during gastrulation in Xenopus.     

3110009F21Rik基因在小鼠胚胎发育中的表达研究

目的:探讨小鼠胚胎发育过程中3110009F21Rik基因的时空特异性表达模式,为后续功能研究奠定基础。方法:对E15.5小鼠胚胎脑组织进行印记分析,检测基因的印记表达状态;应用全胚胎和组织原位杂交技术检测3110009F21Rik基因在E9.5~E15.5小鼠胚胎中的特异性时空表达模式。结果:印记分析显示3110009F21Rik基因在E15.5脑组织中为父母本等位基因双表达;原位杂交结果显示3110009F21Rik基因在E9.5~E15.5脑组织中持续表达,在E9.5~E11.5主要脏器中未检测到,但自E12.5开始在主要脏器中持续表达,随着发育进程进行,目的基因在胚胎骨骼中的相对表达水平逐步升高,至E15.5阶段大部分骨骼中都检测到目的基因表达。结论:3110009F21Rik基因在脑组织中的持续表达和表达模式的动态变化提示其可能参与胚胎发育过程中大脑神经网络的构建,其在软骨原基和软骨中的相对表达逐渐增强表明其可能参与了小鼠胚胎过程中骨的发育和形成及软骨分化。     

The Xenopus laevis Hox 2.1 homeodomain protein is expressed in a narrow band of the hindbrain

The expression pattern of the Xenopus homeodomain protein Hox 2.1 during development was determined using an affinity-purified antibody directed against a carboxyterminal peptide. Nuclear staining was detected in a very narrow band of the hindbrain. This pattern was compared to that of the previously described Xenopus gene XIHbox 1 in serial sections and found to be more anterior than the XIHbox 1 long protein expression but overlapping with that of the short protein. Xenopus Hox 2.1 protein expression is restricted to a much narrower antero-posterior band than that reported for mouse Hox 2.1 RNA expression by in situ hybridization.