The origins of cell communication in the animal kingdom: Notch signalling during embryogenesis and metamorphosis of the demosponge Amphimedon queenslandica.

摘要: Intercellular communication is an essential aspect of multicellular life. In the animal kingdom, molecular signalling pathways fulfil this requirement and provide a conduit for information transfer between cells. The origins ancestral conditions these can be inferred via comparisons their structure deployment in living species. As sponges are one earliest branching metazoan phyla, investigations within lineage important outgroup to which extensive data on bilaterian intercellular compared. Of handful that direct development, I focus Wnt, Notch, Transforming growth factor-β (TGF-β), Hedgehog mechanisms. To determine origins, employ comparative genomics approach annotate incidence domain architectures core pathway components genomes representative species across Holozoa. From analysis infer TGF-β synapomorphies, whereas restricted Eumetazoa sensu stricto. note, identify pre-existing functional modules may have provided foundation emergence lineage. Notch key regulator cell fate decisions during but has been little studied non-bilaterian organisms. report genome emerging model demosponge Amphimedon queenslandica encodes orthologues many canonical genes, further, genes also possess short motifs domains underwrite functionality. Notably, possesses expanded repertoire ligands Fringe glycosyltransferases. These additions indicate significant modifications regulation activity occurred place inventory into organismal context, assay spatial expression receptor five Delta developmental series. reveal differentially expressed embryogenesis development parenchymella larva. order assess significance patterns, it was necessary undertake descriptive study morphology. end, sectioned stages stained them with haematoxylin eosin. This enabled me track ontogeny diverse types relative timing morphogenetic events. Utilising cytological information, linked ciliated posterior pigment ring, anterior pole cells intra-epithelial flask globular cell-type specific leads propose involved determination differentiation multiple lineages – role comparable proposed function Eumetazoa. expressing larvae putative sensory functions. If directly related eumetazoans, active since dawn Metazoa. post-embryonic larval settlement metamorphosis. demonstrate competent larvae, most notably cells, primary sites contact larva benthos. Using chemical inhibitor pathway, show blocking significantly perturbs ability settle undergo experiments suggest additional regulating critical transition free-swimming benthic adults Amphimedon.