Publication Date:
2021-03-29
Description:
While components of the pathway that establishes
left-right asymmetry have been identified in diverse
animals, from vertebrates to flies, it is striking that
the genes involved in the first symmetry-breaking
step remain wholly unknown in the most obviously
chiral animals, the gastropod snails. Previously,
research on snails was used to show that left-right
signaling of Nodal, downstream of symmetry
breaking, may be an ancestral feature of the Bilateria
[1, 2]. Here, we report that a disabling mutation in
one copy of a tandemly duplicated, diaphanousrelated
formin is perfectly associated with symmetry
breaking in the pond snail. This is supported by the
observation that an anti-formin drug treatment converts
dextral snail embryos to a sinistral phenocopy,
and in frogs, drug inhibition or overexpression by
microinjection of formin has a chirality-randomizing
effect in early (pre-cilia) embryos. Contrary to expectations
based on existingmodels [3–5],wediscovered
asymmetric gene expression in 2- and 4-cell snail embryos,
preceding morphological asymmetry. As the
formin-actin filament has been shown to be part of
an asymmetry-breaking switch in vitro [6, 7], together
these results are consistent with the view that animals
with diverse body plans may derive their asymmetries
from the same intracellular chiral elements [8].
Keywords:
Formin; Left-Right Asymmetry; Pond Snail; Frog
;
551
Language:
English
Type:
article
,
publishedVersion
Permalink