Xenopus Pkdcc1 and Pkdcc2 Are Two New Tyrosine Kinases Involved in the Regulation of JNK Dependent Wnt/PCP Signaling Pathway

Protein Kinase Domain Containing, Cytoplasmic (PKDCC) is a protein kinase which has been implicated in longitudinal bone growth through regulation of chondrocytes formation. Nevertheless, the mechanism by which this occurs remains unknown. Here, we identified two new members of the PKDCC family, Pkdcc1 and Pkdcc2 from Xenopus laevis. Interestingly, our knockdown experiments revealed that these two proteins are both involved on blastopore and neural tube closure during gastrula and neurula stages, respectively. In vertebrates, tissue polarity and cell movement observed during gastrulation and neural tube closure are controlled by Wnt/Planar Cell Polarity (PCP) molecular pathway. Our results showed that Pkdcc1 and Pkdcc2 promote the recruitment of Dvl to the plasma membrane. But surprisingly, they revealed different roles in the induction of a luciferase reporter under the control of Atf2 promoter. While Pkdcc1 induces Atf2 expression, Pkdcc2 does not, and furthermore inhibits its normal induction by Wnt11 and Wnt5a. Altogether our data show, for the first time, that members of the PKDCC family are involved in the regulation of JNK dependent Wnt/PCP signaling pathway.Fundacao Ciencia e Tecnologia - IP; IBB/CBME, LA [PTDC/BIA-BCM/69912/2006, Pest-OE/EQB/LA0023/2013]; FCTinfo:eu-repo/semantics/publishedVersio

The distribution of terrestrial pest gastropods and their damage to agricultural crops in Kandy and Nuwara Eliya districts in Sri Lanka

An island wide survey from 1999 to 2002 in Sri Lanka highlighted the presence of 18 species of exotic snails and slugs, of which most were identified as pests of agriculture crops. However, since this survey, no studies on pest gastropods have been carried out in the country. Hence, the present study was carried out in Kandy and Nuwara Eliya districts in approximately 15 hectares of agricultural land to determine the current status of these gastropods. During the study, a total of 14 terrestrial gastropod species were recorded from agricultural lands of which eight species were recognized as exotic pest gastropods. They were Deroceras reticulatum, Laevicaulis altae, Mariaella dussumieri, Milax gagates, Lissachatina fulica, Bradybaena similaris, Allopeas gracile and Subulina octona. The damage from pest gastropods was observed in many crops and especially in the seedling or nursery stage plants. The highest damage to crops in Nuwara Eliya and Kandy districts were caused by D. reticulatum and Lissachatina fulica respectively. The study indicated that the distribution range of many of these pest gastropods, especially Laevicaulis altae and Lissachatina fulica has increased during the past fifteen years. Elevation is a key environmental factor that affects their distribution in these districts

Functional Analysis of Wnt Signaling in the Early Sea Urchin Embryo Using mRNA Microinjection

The Wnt pathway is a highly conserved signal transduction pathway that plays many critical roles in early animal development. Recent studies have shown that this pathway plays a conserved role in the specification and patterning of the animal – vegetal (A – V) axis in sea urchins and sea anemones. These observations have suggested that the common ancestor to cnidarians and bilaterians used the Wnt signaling pathway for specifying and patterning this maternally established axis. Because the A – V axis plays a critical role in germ layer segregation, a better understanding of how the Wnt pathway is regulated along the A – V axis will provide key insight into the molecular mechanisms regulating germ layer segregation and germ layer evolution in animal embryos. Here, we provide a detailed protocol for using mRNA microinjection that can be used to analyze Wnt signaling in early sea urchin embryos. This protocol can also be adapted to introduce morpholino anti-sense oligonucleotides into sea urchin embryos

Wnt Signaling in the Early Sea Urchin Embryo

Wnt signaling regulates a remarkably diverse array of cellular and developmental events during animal embryogenesis and homeostasis. The crucial role that Wnt signaling plays in regulating axial patterning in early embryos has been particularly striking. Recent work has highlighted the conserved role that canonical Wnt signaling plays in patterning the animal-vegetal (A-V) axis in sea urchin and sea anemone embryos. In sea urchin embryos, the canonical Wnt signaling pathway is selectively turned on in vegetal cells as early as the 16-cell stage embryo, and signaling through this pathway is required for activation of the endomesodermal gene regulatory network. Loss of nuclear beta-catenin signaling animalizes the sea urchin embryo and blocks pattern formation along the entire A-V axis. Nuclear entry of beta-catenin into vegetal cells is regulated cell autonomously by maternal information that is present at the vegetal pole of the unfertilized egg. Analysis of Dishevelled (Dsh) regulation along the A-V axis has revealed the presence of a cytoarchitectural domain at the vegetal pole of the unfertilized sea urchin egg. This vegetal cortical domain appears to be crucial for the localized activation of Dsh at the vegetal pole, but the precise mechanisms are unknown. The elucidation of how Dsh is selectively activated at the vegetal cortical domain is likely to provide important insight into how this enigmatic protein is regulated during canonical Wnt signaling. Additionally, this information will shed light on the origins of embryonic polarity during animal evolution. This chapter examines the roles played by the canonical Wnt signaling pathway in the specification and patterning of the A-V axis in the sea urchin. These studies have led to the identification of a novel role for canonical Wnt signaling in regulating protein stability, and continued studies of Wnt signaling in this model system are likely to reveal additional roles for this pathway in regulating early patterning events in embryos