CSB328H1 Lecture Notes - Lecture 9: Schmidtea Mediterranea, Catenin, Dishevelled
28 Aug 2019
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Restore the head regeneration ability in d. lacteum: anterior portion amputated, observe tail regeneration tail piece will degenerate and show no regeneration, rna interference (rnai) experiment injection of b-catenin1 dsrna leads to head/trunk regeneration. Rnai causes degradation of b-catenin transcript: when we do rnai experiments, not all product is knocked out (it is simply reduced) Complete elimination of b-catenin causes formation of multiple heads: b-catenin dsrna injection in a normal worm (no amputation) restructuring tail turs into many heads. Inhibition of wnt signaling is required for head formation. What stimulated the formation of heads: appearance of notum indicates where the head will form. Notum molecule appears only at anterior wound margin: notum is an inhibitor of wnt signalling. Lipid moiety on wnt needed for binding to receptor: notum hydrolase deacylates wnt and lipid is cleaved off, de-lipidated wnt cannot bind to receptors no wnt signaling, notum inhibits wnt! B-catenin rnai phenotype epistatic to notum rnai phenotype.
