PT  - JOURNAL ARTICLE
AU  - Carmen Andrikou
AU  - Andreas Hejnol
TI  - FGF signaling induces mesoderm in members of Spiralia
AID  - 10.1101/2020.08.13.249714
DP  - 2020 Jan 01
TA  - bioRxiv
PG  - 2020.08.13.249714
4099  - http://biorxiv.org/content/early/2020/08/13/2020.08.13.249714.short
4100  - http://biorxiv.org/content/early/2020/08/13/2020.08.13.249714.full
AB  - FGF signaling is involved in mesoderm induction in deuterostomes, but not in flies and nematodes, where it has a role in mesoderm patterning and migration. However, comparable studies in other protostomic taxa are missing in order to decipher whether this mesoderm-inducing function of FGF extends beyond the lineage of deuterostomes. Here, we investigated the role of FGF signaling during mesoderm development in three species of lophophorates, a clade within the protostome group Spiralia. Our gene expression analyses show that the molecular patterning of mesoderm development is overall conserved between brachiopods and phoronids, but the spatial and temporal recruitment of transcription factors differs significantly. Moreover, inhibitor experiments demonstrate that FGF signaling is involved in mesoderm formation, morphogenetic movements of gastrulation and posterior axial elongation. Our findings suggest that the inductive role of FGF in mesoderm possibly predates the origin of deuterostomes.Competing Interest StatementThe authors have declared no competing interest.