Matches in SemOpenAlex for { <https://semopenalex.org/work/W2765821418> ?p ?o ?g. }
- W2765821418 abstract "Author(s): Flores, Vanessa Rae | Advisor(s): Weisblat, David A | Abstract: Evolutionary developmental biology (Evo-Devo) studies the relationships between changes in the genome, development and body plan throughout evolutionary history. In Evo-Devo, the development of different species is compared to determine similarities and differences, which are interpreted in light of phylogenetic relationships. This helps us reconstruct ancestral states and understand the level of conservation and plasticity of developmental signaling pathways.Molecular phylogenies have revealed three bilaterian superphyla: Lophotrochozoa , Ecdysozoa, and Deuterostomia. All three superphyla contain both segmented and non-segmented taxa, and the question of when and/or how often this trait evolved remains open. To understand this further we must compare species from all three superphyla, however, most developmental models are drawn from Ecdysozoa and Deuterostomia. Helobdella austinensis is a useful model for studying segmentation in Lophotrochozoa. They have large, identifiable blastomeres and develop via largely stereotyped cell lineages. All the segmental mesodermal and ectodermal tissues of the leech arise from a posterior growth zone (PGZ) made of five bilateral pairs of lineage restricted segmentation stem cells (teloblasts) and their mitotic progeny. Cell lineage analyses reveal that leeches undergo a distinct, lineage-driven process of segmentation, as opposed to a boundary-driven process operating in vertebrate and arthropod models. The goal of this work is to contribute to the understanding of the molecular process regulating the PGZ of Helobdella austinensis, focusing on the Wnt signaling pathway. With this knowledge, we can make comparisons with established model systems and draw inferences about the ancestry of this trait. This signaling pathway is conserved throughout bilaterian animals as a regulator of anterior-posterior patterning, segmentation, and stem cell regulation. It has previously been found that 10/13 of the Wnt ligands encoded in the Helobdella genome are expressed in the PGZ. I found activating the Wnt pathway using the small molecule lithium chloride (LiCl), causes the primary neurogenic stem cells (the N teloblasts) of the PGZ to divide symmetrically in a subset of embryos, whereas normally this cell only undergoes highly asymmetric divisions. In some cases, both resulting teloblast-like cells carry out stem cell-like divisions. I also tested for changes in the expression patterns of genes associated with this lineage, and obtained evidence suggesting that β-catenin, a key intermediate in the transduction of Wnt signaling, was upregulated in these embryos. This suggests the Wnt pathway plays a role in the formation of the stereotyped set of leech lineage-restricted stem cells. Gene duplication is a major contributing process to the diversification of genomes. I carried out two investigations aimed at exploring the consequences of this process in Helobdella. One dealt with duplication of an ancestral wnt16 gene, that appears to have occurred at some point in the lineage leading to the leech from a polychaete ancestor. Previous work showed that wnt16a is expressed in ventral ectoderm (N teloblast lineage) between stages 8-10. I show that wnt16b exists in at least two isoforms, and that these are expressed in lateral ectoderm (the O and P lineages). Moreover, the expression of at least one of these isoforms switches from ventrolateral ectoderm (O lineage) to dorsolateral ectoderm (P lineage) during embryogenesis. These results provide evidence that the wnt16 genes have undergone neofunctionalization or subfunctionalization since their duplication. These two genes may contribute to the segmental pattern in the leech by specifying fate and/or division patterns of primary blast cells. I also investigated the consequences of gene duplication within a more rapidly evolving gene family, namely, the innexins, which encode invertebrate gap junctions. In particular, I compared expression patterns in Helobdella to those in the medicinal leech Hirudo verbana, to determine levels of conservation and divergence in the expression of innexin genes that have undergone duplication in the lineages leading to these modern leeches since their last common ancestor.In summary, the work presented here suggests that Wnt signaling plays a role in cell division and/or fate specification in multiple stages of embryogenesis in the leech, and thus supports the conclusion that the function of the Wnt signaling pathway is conserved across distantly related taxa. It also provides examples of divergent gene expression between duplicated genes in two different gene families." @default.
- W2765821418 created "2017-11-10" @default.
- W2765821418 creator A5020457222 @default.
- W2765821418 date "2017-01-01" @default.
- W2765821418 modified "2023-09-27" @default.
- W2765821418 title "Wnt signaling and divergent expression of duplicate genes in the leech Helobdella austinensis" @default.
- W2765821418 cites W1517196956 @default.
- W2765821418 cites W1537776120 @default.
- W2765821418 cites W1761838992 @default.
- W2765821418 cites W1966851885 @default.
- W2765821418 cites W1967269820 @default.
- W2765821418 cites W1968342623 @default.
- W2765821418 cites W1974567196 @default.
- W2765821418 cites W1975919509 @default.
- W2765821418 cites W1983624690 @default.
- W2765821418 cites W1983840232 @default.
- W2765821418 cites W1985113794 @default.
- W2765821418 cites W1989184804 @default.
- W2765821418 cites W1989512459 @default.
- W2765821418 cites W1993001731 @default.
- W2765821418 cites W1993385421 @default.
- W2765821418 cites W1998616017 @default.
- W2765821418 cites W2019370554 @default.
- W2765821418 cites W2019591778 @default.
- W2765821418 cites W2020214205 @default.
- W2765821418 cites W2021118808 @default.
- W2765821418 cites W2022666787 @default.
- W2765821418 cites W2028855615 @default.
- W2765821418 cites W2029482176 @default.
- W2765821418 cites W2030557396 @default.
- W2765821418 cites W2031569719 @default.
- W2765821418 cites W2047920420 @default.
- W2765821418 cites W2050801162 @default.
- W2765821418 cites W2050942392 @default.
- W2765821418 cites W2055770332 @default.
- W2765821418 cites W2065049377 @default.
- W2765821418 cites W2068489317 @default.
- W2765821418 cites W2069325937 @default.
- W2765821418 cites W2071708006 @default.
- W2765821418 cites W2071769324 @default.
- W2765821418 cites W2072594339 @default.
- W2765821418 cites W2073523429 @default.
- W2765821418 cites W2075478382 @default.
- W2765821418 cites W2076681174 @default.
- W2765821418 cites W2077296870 @default.
- W2765821418 cites W2081587092 @default.
- W2765821418 cites W2083935467 @default.
- W2765821418 cites W2089849943 @default.
- W2765821418 cites W2091615587 @default.
- W2765821418 cites W2100492087 @default.
- W2765821418 cites W2107956172 @default.
- W2765821418 cites W2108731933 @default.
- W2765821418 cites W2117740754 @default.
- W2765821418 cites W2124750090 @default.
- W2765821418 cites W2125987139 @default.
- W2765821418 cites W2126135252 @default.
- W2765821418 cites W2128683321 @default.
- W2765821418 cites W2129093626 @default.
- W2765821418 cites W2148617989 @default.
- W2765821418 cites W2149001956 @default.
- W2765821418 cites W2150465697 @default.
- W2765821418 cites W2152695624 @default.
- W2765821418 cites W2153004457 @default.
- W2765821418 cites W2154292479 @default.
- W2765821418 cites W2163125355 @default.
- W2765821418 cites W2170551347 @default.
- W2765821418 cites W2182691744 @default.
- W2765821418 cites W2240027552 @default.
- W2765821418 cites W2416080818 @default.
- W2765821418 cites W2426806805 @default.
- W2765821418 cites W2516986218 @default.
- W2765821418 cites W2605366018 @default.
- W2765821418 hasPublicationYear "2017" @default.
- W2765821418 type Work @default.
- W2765821418 sameAs 2765821418 @default.
- W2765821418 citedByCount "0" @default.
- W2765821418 crossrefType "journal-article" @default.
- W2765821418 hasAuthorship W2765821418A5020457222 @default.
- W2765821418 hasConcept C104317684 @default.
- W2765821418 hasConcept C105702510 @default.
- W2765821418 hasConcept C136764020 @default.
- W2765821418 hasConcept C137620995 @default.
- W2765821418 hasConcept C148737382 @default.
- W2765821418 hasConcept C168601633 @default.
- W2765821418 hasConcept C180746962 @default.
- W2765821418 hasConcept C2776817793 @default.
- W2765821418 hasConcept C2777343278 @default.
- W2765821418 hasConcept C2778961482 @default.
- W2765821418 hasConcept C41008148 @default.
- W2765821418 hasConcept C54355233 @default.
- W2765821418 hasConcept C78458016 @default.
- W2765821418 hasConcept C86803240 @default.
- W2765821418 hasConcept C90132467 @default.
- W2765821418 hasConcept C91066513 @default.
- W2765821418 hasConceptScore W2765821418C104317684 @default.
- W2765821418 hasConceptScore W2765821418C105702510 @default.
- W2765821418 hasConceptScore W2765821418C136764020 @default.
- W2765821418 hasConceptScore W2765821418C137620995 @default.
- W2765821418 hasConceptScore W2765821418C148737382 @default.
- W2765821418 hasConceptScore W2765821418C168601633 @default.