Characterizing the Effects of WLS on WNT1 and WNT3A in Developing Chick Somites
Authors: Ashley Ng, Benjamin Lee
Faculty Supervisor: Kai (Laura) Burrus
Department: Biology
In developing embryos, cellular communication plays critical roles in cell proliferation, specification, and differentiation. The Wnt family of proteins, are sent between producing cells and receiving cells, must be translated, lipid-modified, and escorted to the cell membrane by Wntless (WLS). Wnts are transported to a receiving cell where they bind to Frizzled receptors triggering a reaction within the cell resulting in the transcription of genes. Overexpression of either WNT1 or WNT3A expands dorsal somites in chick embryos, specifically the myotome (precursor to skeletal muscles) and the dermomyotome (gives rise the dermis and myotome), when overexpressed in the neural tube. Previous studies have shown that all lipid-modified Wnts require WLS for function. We found that co-expression of WLS with WNT1, but not WNT3A, augments Wnt signaling in cultured HEK293T cells. This suggests that WLS interacts differently with WNT1 than WNT3A. It is not known if this difference will also be observed in developing chick embryos. We hypothesize that co-expression of WLS will augment the effect of WNT1 on somites more than WNT3A. We then ectopically express WNT1 or WNT3A with or without WLS in the neural tube of chick embryos via electroporation. We immunostain embryo sections with antibodies labeling the myotome and dermomyotome, image via confocal microscopy, and analyze the size of the myotome and dermomyotome with Image J.