Nkds inhibit non-canonical Wnt/PCP signaling. (A) Wild-type embryos have a cyclopia index (CI) of 1, while slb mutants have a CI of 2.80 ± 0.46 (B). (C) slb embryos injected with nkd1 or nkd2a RNA have an increase in cyclopia with a CI of 3.77 and 3.08 respectively. See text for details. (D–I) Analysis of prechordal plate position. (D) Wild-type embryos have a narrow neural plate (double headed arrow) and a prechordal plate that has fully extended past the neuroectoderm and non-neural ectoderm boundary (black arrowhead). (E) slb mutant embryos exhibit a wider neural plate due to impaired C&E (double headed arrow) and reduced extension of the axial mesendoderm (black arrowhead). (F) Injection of wnt11 RNA into slb embryos can rescue the C&E defects in slb embryos. (G) Overexpression of nkd1 or nkd2a RNA in slb embryos exacerbates the axial mesendoderm extension defect. (H) Co-expression of wnt11 with nkd1 or nkd2a results in a phenotype that resembles the nkd overexpression phenotype arguing that Nkds can block Wnt11 signaling. This data is semi-quantified in (I) where moderate is defined as ≤ ∼50% of the hgg expression domain is within the dlx3 expression domain and severe is defined as > ∼50% of the hgg expression domain is within the dlx3 domain. (A–C) 2 dpf, (A) dorsal view, (B, C) ventral views. (D–H) 2–3 somites, anterior view, dorsal is to the top, prechordal plate marked by hgg (red), neuroectoderm-non neural ectoderm boundary marked by dlx3 (dark purple), developing somites (out of view) marked by dlC for staging confirmation.
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