Morphological changes and two Nodal paralogs drive left-right asymmetry in the squamate veiled chameleon (C. calyptratus)

Frontiers in Cell and Developmental Biology

Cell and Developmental Biology

Sarah E. Smith¹  Melainia McClain¹  Fengli Guo¹  Natalia A. Shylo¹  Andrew J. Price¹  Paul A. Trainor² 

[1] Stowers Institute for Medical Research, Kansas City, MO, United States;Stowers Institute for Medical Research, Kansas City, MO, United States;Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, MO, United States;

关键词: left-right patterning;    left-right organizer;    gastrulation;    cilia;    cell migration;    Nodal;    lefty;    veiled chameleon;   

DOI  :  10.3389/fcell.2023.1132166

 received in 2022-12-26, accepted in 2023-02-23,  发布年份 2023

来源: Frontiers

【 摘 要 】

The ancestral mode of left-right (L-R) patterning involves cilia in the L-R organizer. However, the mechanisms regulating L-R patterning in non-avian reptiles remains an enigma, since most squamate embryos are undergoing organogenesis at oviposition. In contrast, veiled chameleon (Chamaeleo calyptratus) embryos are pre-gastrula at oviposition, making them an excellent organism for studying L-R patterning evolution. Here we show that veiled chameleon embryos lack motile cilia at the time of L-R asymmetry establishment. Thus, the loss of motile cilia in the L-R organizers is a synapomorphy of all reptiles. Furthermore, in contrast to avians, geckos and turtles, which have one Nodal gene, veiled chameleon exhibits expression of two paralogs of Nodal in the left lateral plate mesoderm, albeit in non-identical patterns. Using live imaging, we observed asymmetric morphological changes that precede, and likely trigger, asymmetric expression of the Nodal cascade. Thus, veiled chameleons are a new and unique model for studying the evolution of L-R patterning.

【 授权许可】

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Copyright © 2023 Shylo, Smith, Price, Guo, McClain and Trainor.