In addition to the cell biological details underlying gastrulation in Nematostella, we are also very interested in the regulatory mechanisms involved in organizing these processes. Our early studies have focused on the transcription factor Snail, as Snail family members have been shown to be crucial regulators of cell adhesion and epithelial-to-mesenchymal transitions (EMTs) in a variety of metazoan species. In Nematostella, there are two Snail genes, and both are expressed in the endoderm prior to and during gastrulation.
Expression dynamics of the transcription factors NvSnailA (blue) and NvFoxA (red) during gastrulation, revealed by wholemount in situ hybridization.
However, both morpholino knockdown experiments and overexpression experiments via microinjection of NvSnailA mRNA fail to produce mutant phenotypes, suggesting that the role of Snail in Nematostella may not be so straightforward.
Overexpression of a SnailA-GFP fusion protein does not result in an ectopic invagination, and embryos develop normally.
Injection of splice-blocking morpholinos that result in the production of nonfunctional Snail protein have no effect on gastrulation (right). RT-PCR results indicate that the morpholinos are effective (below).
Current work is aimed at identifying and studying the mechanistic roles of other genes likely to be involved in regulating gastrulation in Nematostella.
Regulation of gastrulation in Nematostella