ACTIVATION OF 2 CYNOPS GENES, FORK HEAD AND SONIC HEDGEHOG, IN ANIMALCAP EXPLANTS

We have isolated cDNAs of sonic hedgehog (shh) and fork head from Cyno ps (Japanese newt) embryo. Their expression was investigated in relati on to mesoderm induction by activin and basic fibroblast growth factor (bFGF). Different from these homologs in Xenopus, they are activated not only by activin but also by bFGF in animal cap explants, showing a difference of animal pole cells in responsiveness to bFGF between Cyn ops acid Xenopus. We also investigated the involvement of fork head in shh activation. The expression of shh was activated in animal caps wh ich overexpressed either of two Xenopus fork head homologs, pintallavi s/XFD-1 or XFKH-1/XFD-1', indicating that fork head up-regulates the t ranscription of shh in Cynops embryo. (C) 1996 Academic Press, Inc.