BMP signaling patterns DV and directive body axes in bilaterally symmetric animals – Bilateria and anthozoan Cnidaria. However, it is unclear whether DV = directive. In order to gain a better understanding of the bilaterian and anthozoan secondary axis we wanted to learn whether the direct target genes of BMP signaling are shared in the sea anemone Nematostella and in Bilateria. ChIP-Seq showed that mostly they are not – surprisingly, not even between flies and frogs, not to mention Nematostella – but some targets are well-conserved.  One of such targets conserved between Nematostellaand frog was ZSWIM4-6, which is highly responsive to slightest changes in the BMP signalling intensity and encodes a protein with an unclear role. We showed that ZSWIM4-6 is a nuclear protein dampening the BMP signaling gradient – probably by destabilizing nuclear pSMAD1/5. The work of our co-authors in Patrick Müller's lab suggests that this function is conserved in zebrafish. However, strikingly, in Nematostella, ZSWIM4/6 might have an additional function:without it, genes repressed by BMP signalling become de-repressed in spite of higher pSMAD1/5! So, ZSWIM4/6 likely acts as a mediator of BMP driven gene repression.

For the full text see https://elifesciences.org/articles/80803