eprintid: 10053551 rev_number: 27 eprint_status: archive userid: 608 dir: disk0/10/05/35/51 datestamp: 2018-08-01 10:04:02 lastmod: 2021-09-28 22:29:25 status_changed: 2018-08-01 10:04:02 type: article metadata_visibility: show creators_name: Ren, X creators_name: Hamilton, N creators_name: Müller, F creators_name: Yamamoto, Y title: Cellular rearrangement of the prechordal plate contributes to eye degeneration in the cavefish ispublished: pub divisions: UCL divisions: B02 divisions: C08 divisions: D09 divisions: F96 keywords: Astyanax mexicanus, Eye degeneration, Eye development, Nodal signaling, Spemann's organiser note: This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. abstract: Astyanax mexicanus consists of two different populations: a sighted surface-dwelling form (surface fish) and a blind cave-dwelling form (cavefish). In the cavefish, embryonic expression of sonic hedgehog a (shha) in the prechordal plate is expanded towards the anterior midline, which has been shown to contribute to cavefish specific traits such as eye degeneration, enhanced feeding apparatus, and specialized brain anatomy. However, it is not clear how this expanded expression is achieved and which signaling pathways are involved. Nodal signaling has a crucial role for expression of shh and formation of the prechordal plate. In this study, we report increased expression of prechordal plate marker genes, nodal-related 2 (ndr2) and goosecoid (gsc) in cavefish embryos at the tailbud stage. To investigate whether Nodal signaling is responsible for the anterior expansion of the prechordal plate, we used an inhibitor of Nodal signaling and showed a decreased anterior expansion of the prechordal plate and increased pax6 expression in the anterior midline in treated cavefish embryos. Later in development, the lens and optic cup of treated embryos were significantly larger than untreated embryos. Conversely, increasing Nodal signaling in the surface fish embryo resulted in the expansion of anterior prechordal plate and reduction of pax6 expression in the anterior neural plate together with the formation of small lenses and optic cups later in development. These results confirmed that Nodal signaling has a crucial role for the anterior expansion of the prechordal plate and plays a significant role in cavefish eye development. We showed that the anterior expansion of the prechordal plate was not due to increased total cell number, suggesting the expansion is achieved by changes in cellular distribution in the prechordal plate. In addition, the distribution of presumptive prechordal plate cells in Spemann's organiser was also altered in the cavefish. These results suggested that changes in the cellular arrangement of Spemann's organiser in early gastrulae could have an essential role in the anterior expansion of the prechordal plate contributing to eye degeneration in the cavefish. date: 2018-09-15 date_type: published official_url: https://doi.org/10.1016/j.ydbio.2018.07.017 oa_status: green full_text_type: other language: eng primo: open primo_central: open_green verified: verified_manual elements_id: 1571091 doi: 10.1016/j.ydbio.2018.07.017 pii: S0012-1606(18)30126-X lyricists_name: Yamamoto, Yoshiyuki lyricists_id: YYAMA10 actors_name: Stacey, Thomas actors_id: TSSTA20 actors_role: owner full_text_status: public publication: Developmental Biology volume: 441 number: 2 pagerange: 221-234 event_location: United States issn: 1095-564X citation: Ren, X; Hamilton, N; Müller, F; Yamamoto, Y; (2018) Cellular rearrangement of the prechordal plate contributes to eye degeneration in the cavefish. Developmental Biology , 441 (2) pp. 221-234. 10.1016/j.ydbio.2018.07.017 <https://doi.org/10.1016/j.ydbio.2018.07.017>. Green open access document_url: https://discovery.ucl.ac.uk/id/eprint/10053551/3/Yamamoto%20DEVELOPMENTALBIOLOGY_2018_90_Yamamoto16072018.pdf