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BMP controls dorsoventral and neural patterning in indirect-developing hemichordates providing insight into a possible origin of chordates

出版日期:2019-06-26

PNAS 116 (2019):12925-12932

https://www.pnas.org/content/116/26/12925

A defining feature of chordates is the unique presence of a dorsal hollow neural tube that forms by internalization of the ectodermal neural plate specified via inhibition of BMP signaling during gastrulation. While BMP controls dorsoventral (DV) patterning across diverse bilaterians, the BMP-active side is ventral in chordates and dorsal in many other bilaterians. How this phylum-specific DV inversion occurs and whether it is coupled to the emergence of the dorsal neural plate are unknown. Here we explore these questions by investigating an indirect-developing enteropneust from the hemichordate phylum, which together with echinoderms form a sister group of the chordates. We found that in the hemichordate larva, BMP signaling is required for DV patterning and is sufficient to repress neurogenesis. We also found that transient overactivation of BMP signaling during gastrulation concomitantly blocked mouth formation and centralized the nervous system to the ventral ectoderm in both hemichordate and sea urchin larvae. Moreover, this mouthless, neurogenic ventral ectoderm displayed a medial-to-lateral organization similar to that of the chordate neural plate. Thus, indirectdeveloping deuterostomes use BMP signaling in DV and neural patterning, and an elevated BMP level during gastrulation drives pronounced morphological changes reminiscent of a DV inversion. These findings provide a mechanistic basis to support the hypothesis that an inverse chordate body plan emerged from an indirectdeveloping ancestor by tinkering with BMP signaling.

 


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115台北市南港區研究院路二段128號
Tel: 02-27899515
Fax: 02-27858059
icob@gate.sinica.edu.tw
Copyright © ICOB 2013. All rights reserved. 最佳瀏覽網頁方式請用最新版IE11或其他瀏覽器 /瀏覽人數:1515267--
 瀏覽人數:1515267