Journal Article
Natural reversal of cavefish heart asymmetry is controlled by Sonic Hedgehog effects on the left-right organizer
Ng, M., Ma, L., Shi, J. and Jeffery, W.R.
Record Number:
6903
Year:
2024
Journal:
Development
Volume:
151, dev202611
Abstract:
The direction of left-right visceral asymmetry is conserved in vertebrates. Deviations of the standard asymmetric pattern are rare, and the underlying mechanisms are not understood. Here, we use the teleost Astyanax mexicanus, consisting of surface fish with normal left-oriented heart asymmetry and cavefish with high levels of reversed right-oriented heart asymmetry, to explore natural changes in asymmetry determination. We show that Sonic Hedgehog (Shh) signaling is increased at the posterior midline, Kupffer’s vesicle (the
teleost left-right organizer) is enlarged and contains longer cilia, and the number of dorsal forerunner cells is increased in cavefish. Furthermore, Shh increase in surface fish embryos induces asymmetric changes resembling the cavefish phenotype. Asymmetric expression of the Nodal antagonist Dand5 is equalized or reversed in cavefish, and Shh
increase in surface fishmimics changes in cavefish dand5 asymmetry. Shh decrease reduces the level of right-oriented heart asymmetry in cavefish. Thus, naturally occurring modifications in cavefish heart asymmetry are controlled by the effects of Shh signaling on left-right organizer function.
KEY WORDS: Cavefish, Heart asymmetry, Sonic Hedgehog,
Left-right organizer, dand5 asymmetry
Times Cited:
1
Relevent Species: