Xenopus laevis embryos injected with follistatin developed abnormally
with enlarged anterior structures and defective tails. Histological se
ctions reveal that these follistatin treated embryos contain large amo
unt of notochordal tissue that fails to elongate. Embryonic responses
to follistatin are dose and stage specific. These results suggested th
at follistatin contributes to body axis formation, with its most visib
le effect on notochord formation.