Figure 4. Secreted molecules with roles in planarian brain regeneration.

(A) Expression patterns of LDLRR-1, LDLRR-2, LDLRR-3, and F-spondin were determined by ISH for uninjured worms (top) and tail fragments two days after amputation (bottom). (B) The domain architectures of LDLRR-1 and LDLRR-3. (C) Coexpression of the indicated genes by fluorescent in situ hybridization (FISH). All LDLRR-3⁺ cells express LDLRR-1 (16/16), but only about half of LDLRR-1⁺cells express LDLRR-3 (16/31). LDLRR-3⁺ cells do not express smedwi-1 (0/34), although these cells are often found in proximity to one another. LDLRR-1, LDLRR-3, and F-spondin are not expressed in mhc⁺ muscle cells (0/8, 0/23, and 0/6 respectively). LDLRR FISH experiments were performed on whole worms and F-spondin FISH was performed on 2d regenerating animals. (D) The domain architecture of F-spondin. Scale bars: 500 µm (A), 20 µm (C).

DOI: http://dx.doi.org/10.7554/eLife.17002.011

Figure 4—figure supplement 1. Parenchymal genes are irradiation-insensitive and do not influence wound response.

(A) Planarians were subjected to ISH with smedwi-1, F-spondin, and LDLRR-3 probes after mock irradiation as well as 1, 3, and 7 days post-irradiation. While smedwi-1 transcript is lost quickly, F-Spondin and LDLRR-3 transcripts are still present at 7 dpi, when most animals were lysing and dying. (B) Diagram of amputation schema for wound-response genes. Animals were fed dsRNA three times before amputation as in Figure 2A. (C) Wound-response genes follistatin, jun, inhibin, and runt were examined by ISH after RNAi and amputation. All genes were upregulated despite knockdown of the genes indicated, suggesting that LDLRR and F-spondin genes do not inhibit the general wound response. Scale bars: 500 µm (A, C).

DOI: http://dx.doi.org/10.7554/eLife.17002.012